The figure below, from Brooks et al. (2005), shows a graph relating nitrogen balance and protein intake. A nitrogen balance of zero is a state in which body protein mass is stable; that is, it is neither increasing nor decreasing. The graph was taken from this classic study by Meredith et al. The participants in the study were endurance exercisers. As you can see, age is not much of a factor for nitrogen balance in this group.
Nitrogen balance is greater than zero (i.e., an anabolic state) for the vast majority of the participants at 1.2 g of protein per kg of body weight per day. To convert lbs to kg, divide by 2.2. A person weighing 100 lbs (45 kg) would need 55 g/d of protein; a person weighing 155 lbs (70 kg) would need 84 g/d; someone weighing 200 lbs (91 kg) would need 109 g/d.
The above numbers are overestimations of the amounts needed by people not doing endurance exercise, because endurance exercise tends to lead to muscle loss more than rest or moderate strength training. One way to understand this is compensatory adaptation; the body adapts to endurance exercise by shedding off muscle, as muscle is more of a hindrance than an asset for this type of exercise.
Total calorie intake has a dramatic effect on protein requirements. The above numbers assume that a person is getting just enough calories from other sources to meet daily caloric needs. If a person is in caloric deficit, protein requirements go up. If in caloric surplus, protein requirements go down. Other factors that increase protein requirements are stress and wasting diseases (e.g., cancer).
But what if you want to gain muscle?
Wilson & Wilson (2006) conducted an extensive review of the literature on protein intake and nitrogen balance. That review suggests that a protein intake beyond 25 percent of what is necessary to achieve a nitrogen balance of zero would have no effect on muscle gain. That would be 69 g/d for a person weighing 100 lbs (45 kg); 105 g/d for a person weighing 155 lbs (70 kg); and 136 g/d for someone weighing 200 lbs (91 kg). For the reasons explained above, these are also overestimations.
What if you go well beyond these numbers?
The excess protein will be used primarily as fuel; that is, it will be oxidized. In fact, a large proportion of all the protein consumed on a daily basis is used as fuel, and does not become muscle. This happens even if you are a gifted bodybuilder that can add 1 lb of protein to muscle tissue per month. So excess protein can make you gain body fat, but not by protein becoming body fat.
Dietary protein does not normally become body fat, but will typically be used in place of dietary fat as fuel. This will allow dietary fat to be stored. Dietary protein also leads to an insulin response, which causes less body fat to be released. In this sense, protein has a fat-sparing effect, preventing it from being used to supply the energy needs of the body. As long as it is available, dietary protein will be favored over dietary or body fat as a fuel source.
Having said that, if you were to overeat anything, the best choice would be protein, in the absence of any disease that would be aggravated by this. Why? Protein contributes fewer calories per gram than carbohydrates; many fewer when compared with dietary fat. Unlike carbohydrates or fat, protein almost never becomes body fat under normal circumstances. Dietary fat is very easily converted to body fat; and carbohydrates become body fat when glycogen stores are full. Finally, protein seems to be the most satiating of all macronutrients, perhaps because natural protein-rich foods are also very nutrient-dense.
It is not very easy to eat a lot of protein without getting also a lot of fat if you get your protein from natural foods; as opposed to things like refined seed/grain products or protein supplements. Exceptions are organ meats and seafood, which generally tend to be quite lean and protein-rich.
References
Brooks, G.A., Fahey, T.D., & Baldwin, K.M. (2005). Exercise physiology: Human bioenergetics and its applications. Boston, MA: McGraw-Hill.
Wilson, J., & Wilson, G.J. (2006). Contemporary issues in protein requirements and consumption for resistance trained athletes. Journal of the International Society of Sports Nutrition, 3(1), 7-27.
Thursday, December 30, 2010
Tuesday, December 28, 2010
How much dietary protein can you store in muscle? About 15 g/d if you are a gifted bodybuilder
Let us say you are one of the gifted few who are able to put on 1 lb of pure muscle per month, or 12 lbs per year, by combining strength training with a reasonable protein intake. Let us go even further and assume that the 1 lb of muscle that we are talking about is due to muscle protein gain, not glycogen or water. This is very uncommon; one has to really be genetically gifted to achieve that.
And you do that by eating a measly 80 g of protein per day. That is little more than 0.5 g of protein per lb of body weight if you weigh 155 lbs; or 0.4 per lb if you weigh 200 lbs. At the end of the year you are much more muscular. People even think that you’ve been taking steroids; but that just came naturally. The figure below shows what happened with the 80 g of protein you consumed every day. About 15 g became muscle (that is 1 lb divided by 30) … and 65 g “disappeared”!
Is that an amazing feat? Yes, it is an amazing feat of waste, if you think that the primary role of protein is to build muscle. More than 80 percent of the protein consumed was used for something else, notably to keep your metabolic engine running.
A significant proportion of dietary protein also goes into the synthesis of albumin, to which free fatty acids bind in the blood. (Albumin is necessary for the proper use of fat as fuel.) Dietary protein is also used in the synthesis of various body tissues and hormones.
Dietary protein does not normally become body fat, but can be used in place of fat as fuel and thus allow more dietary fat to be stored. It leads to an insulin response, which causes less body fat to be released. In this sense, dietary protein has a fat-sparing effect, preventing it from being used to supply the energy needs of the body.
Nevertheless, the fat-sparing effect of protein is lower than that of another "macronutrient" – alcohol. That is, alcohol takes precedence over carbohydrates for use as fuel. However, protein takes precedence over carbohydrates. Neither alcohol nor protein typically becomes body fat. Carbohydrates can become body fat, but only when glycogen stores are full.
What does this mean?
As it turns out, a reasonably high protein intake seems to be quite healthy, and there is nothing wrong with the body using protein to feed its metabolism.
Having said that, one does not need enormous amounts of protein to keep or even build muscle if one is getting enough calories from other sources.
In my next post I’ll talk a little bit more about that.
And you do that by eating a measly 80 g of protein per day. That is little more than 0.5 g of protein per lb of body weight if you weigh 155 lbs; or 0.4 per lb if you weigh 200 lbs. At the end of the year you are much more muscular. People even think that you’ve been taking steroids; but that just came naturally. The figure below shows what happened with the 80 g of protein you consumed every day. About 15 g became muscle (that is 1 lb divided by 30) … and 65 g “disappeared”!
Is that an amazing feat? Yes, it is an amazing feat of waste, if you think that the primary role of protein is to build muscle. More than 80 percent of the protein consumed was used for something else, notably to keep your metabolic engine running.
A significant proportion of dietary protein also goes into the synthesis of albumin, to which free fatty acids bind in the blood. (Albumin is necessary for the proper use of fat as fuel.) Dietary protein is also used in the synthesis of various body tissues and hormones.
Dietary protein does not normally become body fat, but can be used in place of fat as fuel and thus allow more dietary fat to be stored. It leads to an insulin response, which causes less body fat to be released. In this sense, dietary protein has a fat-sparing effect, preventing it from being used to supply the energy needs of the body.
Nevertheless, the fat-sparing effect of protein is lower than that of another "macronutrient" – alcohol. That is, alcohol takes precedence over carbohydrates for use as fuel. However, protein takes precedence over carbohydrates. Neither alcohol nor protein typically becomes body fat. Carbohydrates can become body fat, but only when glycogen stores are full.
What does this mean?
As it turns out, a reasonably high protein intake seems to be quite healthy, and there is nothing wrong with the body using protein to feed its metabolism.
Having said that, one does not need enormous amounts of protein to keep or even build muscle if one is getting enough calories from other sources.
In my next post I’ll talk a little bit more about that.
Sunday, December 26, 2010
Hydroponics and health
I've had friends of mine try to get me into hydroponics before, but I haven't ever been truly interested until today, when @TheEconomist tweeted links to these videos on "vertical farming," the brainchild of Dickson Despommier, professor of public health in environmental health sciences at Columbia University.
The magazine reports mainly on this urban-type agriculture as a way to bring local, sustainable food to places like New York City, the logistical problems, and what this might mean for battling climate change. There was also mention of how hydroponics allows for introduction of nutrients in the water, reduces need for fertilizing, and how it being a closed system recycles water.
And, the interview (below) with Despommier speaks to how this idea could potentially turn the "parasitism" of cities into productive ecosystems.
These are neat topics, although I still wonder about how realistic it is on a grand scale based on concerns about use of artificial lighting, expense, and so on.
However, from a nutritional standpoint, urban agriculture does lend to great possibilities for producing food that is healthier, cleaner and safer. As I see it, the possibilities for human health is endless.
Urban agriculture allows for much more control over heavy metals with use of refined minerals in the hydroponics fertilizer. Plus, you could standardized to reasonable exactness, the amounts the plants would receive of minerals. Then, with a controlled environment, the potential of having a standardized product comes into the picture too.
This might sound really lame to some people, but it's a nutritionist's dream -- Can you imagine walking into a grocery store and seeing fruits and vegetables with standardized nutrition facts panels complete with quantities of minerals, and possibly vitamins and phytonutrients?
You could also do a much better job controlling and enhancing the flavor of plants, which is highly dependent on what comes through the water. By adding in concentrated extracts, for example, of vanilla or orange, you could give plants certain notes or essences.
Anyway, I might have to head down to Tucson, Arizona, to check out what's currently largest system of hydroponics in the country -- and maybe have a bite of something tasty.
I might also have to order me some kind of home hydroponics system.
Labels:
Future Health
Thursday, December 23, 2010
How diet shaped human evolution
Anyone who is keenly interested in having a better understanding of why we eat what we eat as human beings should take an hour or so to watch this introductory talk given by anthropologist Teresa Steele, of UC Davis, given at the California Academy of Sciences on the topic of evolution of the human diet.
I found her talk fascinating, especially because I've been highly interested in how the use of fire and aquatic animals may have played a part in fueling human brain growth, so I ended up taking copious notes. I should note that there isn't anything new presented here, but Steele is excellent at presenting the chronology. If you don't have an hour to watch, then just see my notes below chapter by chapter from "Australopithecus to agriculture."
Human diet is unique among apes
Steele finds that diet is central to her research. "If we want to live, we have to eat," she says. Food is what ultimately supports demographic populations. One thing that is unique about humans in comparison to other apes is a long childhood, a long learning period, that is required for acquiring the knowledge necessary to become successful foragers in a wide environment. After all, humans have exploited almost every nutrient resource in their short time on the Earth.
Another unique thing is how much meat we consume. A large portion of our calories comes from meat. Unlike chimpanzees, who eat the most meat among apes, human eat about 10 times more, Steele said. And we eat animals that are usually larger than us like wildebeasts, reindeer, and mammoths. Steele shows a graph comparing chimp diets to that of tropical hunter gatherers groups, who typically eat little meat. Other hunter-gatherers of the North like the Inuit eat a diet almost entirely of meat. In general, humans specialize in acquiring nutrient-dense foods meats, tubers, and nuts, while chimps select non-nutrient dense like leaves that are more easily collected.
Research themes
When did these differences evolve? Steele presents us with her research themes, which include the following:
What methods does Steele use to construct ancient human diets? She says that zooarchaeology and tool analyses gives us a window into ancient demographies. There are stone, bone and antler tools. And, on occasion, organic wood and plant tools are preserved. Also, biological anthropology helps tell us more such as skeletal morphology and bone chemistry.
Lucy's diet
Steele introduces the diet of Lucy's species first, Austrolopithecus afarensis of 3.7-2.8 mya, who ate a flexible diet suitable for a variety of habitats.
The skeletal biomechanics and dental structure suggest they ate mostly soft fruits and occasional hard seeds. However, Steele says we assume that they may have eaten some meat because chimps eat meat, but it's unclear just how much.
She points out that, recently, there was a groundbreaking discovery published in Nature (and reported in Scientific American by the science writer Kate Wong (Twitter: @katewong) ) of cut-marked bones in Dikika, Ethiopia suggesting Lucy's species even used stone tools for eating meat.
"This has opened up a window," Steele says for more research, especially in the possibility of stone tool use for extracting nutrients from carcasses of smaller animals. It's worth noting that no stone artifacts were found associated with the cut-marked bones (paleoanthropologist John Hawks (Twitter: @johnhawks) has written more about this topic on his blog).
Cut-marked bones 2.5 million years ago
Typically, a discussion of human diet begins at about 2.5 mya when there is an abundance of cut-marked bones (such as the jaw of a wildebeest) and percussion marks from marrow extraction. Marrow has been an important human resource for nutrients up until modern times because it's high in fat, high in calories.
There is also evidence of Oldowan artifacts (hominin stone tools) available so we know what they were using to get to the marrow.
Then, at about 1.8 mya there are a lot more assemblages, more stone tools, as found in Olduvai Gorge, Tanzania, by Mary Leaky. There are also lots of large bodies bovids and carnivores on the landscape. Steele asks, How did these ancient hominids acquire these large carcasses? Is it conceivable that they could've brought down a wildebeast with just tools?
This is where we get into a discussion of scavenging versus hunting, she said. A related discussion is what percentage of the diet was meat-based versus plant-based. Also, were these ancient hominins practicing passive scavenging getting to a carcass to get the last scraps of meat or breaking open bones for marrow. Or was it active scavenging, chasing off carnivores?
These are all active areas of research. For answers, researchers look in locations of lakeside margins. Bovids came to drink, carnivores know this, we look into these locations to try and reconstruct the foraging.
Aquatic animals
Published recently in the springtime, was a paper suggesting that 1.9 mya in East Turkana, there's evidence of Oldowan foraging of carcasses of aquatic animals like crocodiles and turtles. Steele shows a cut marks on a toe bone of a croc, turtle shells and catfish bones.
"For the first time, we see exploitation of aquatic resources highlighting the diversity of diet. Hominins are very opportunistic, exploiting whatever was available," Steele said.
"This also raises a challenge as with cut-marked bones with Dekika, to try to see if there are cut-marks on similar bones," Steele explains. "The small animal component has been overlooked so we may need to look closer."
Steele also discusses another interesting aspect of using aquatic resources (which will interest any nutritionist like myself). The aquatic resources would have been an easier way to access long-chain omega-3 fatty acids, which are also present in organ meats and brain tissues of large animals.
"The long-chain unsaturated fatty acids are needed for brain growth," she explained. "At this time period we do see an expansion of brain sizes, so perhaps there's a relationship here. We need more data, more examples where we see brain expansion with this kind of diet."
Archeulean hunting and scavenging
Moving more recently in time, we see Homo erectus, hominins of larger body size, and who were first to populate Eurasia 1.6 mya to 285 kya. Were they hunting or actively scavenging? This is unclear, but earlier in Archeulan, we see evolution of technology.
Tear-drop shaped hand axes appear and body size changes. The humans are obviously living in social groups. An illustration she uses takes the liberty of showing piles of plant remains used to make wooden spears. The plant use is unknown.
There are a large number of animal bones with few cut marks. So, the question remains, were hominins still minor players as carnivores, simply cutting off limbs and eating elsewhere. The challenge is finding places away from water sites such as in caves.
Also, we start asking questions about use of fire at this time period.
Wood spears
At around 400 kya, Steele shares that there are one or two examples of exceptional preservation of organic materials such as wooden spears (survived in an oxygen-poor environments from marshes of Germany). They are more likely to be thrusting spears. They have been fire-hardened, sharpened, so it indicates use of fire.
Fire is really useful for warmth, protection from predators, for cooking and cooking really changes the nature of food. It helps make inedible foods edible, releases nutrients for our digestive systems. But fire doesn't preserve well.
The earliest known site where fire is documented is in Israel, dated to 780 kya. "We have an indicator of fire use and plant remains. They're preserve better once charred in archaeological sites," Steele says. "We don't find it common until about 300,000 years ago." This is between Oldowan and modern behavior in the Archeulian.
Neandertals
About 200 kya came the Neandertals and they were competent hunters and manufacturers of stone tools. Interestingly, despite these complex behaviors, they did not have as long a childhood. The Neandertals were able to pick up their abilities pretty early in life.
As part of her post-doc in Germany at Max Plank Institute, Steele worked with identifying species in archaeological sites where Neandertals hunted reindeer and bison. She showed antlers, elbows of reindeer fractured for extracting marrow, and examples of bones in discard piles due to little meat.
"We also see very little carnivore involvement and abundant human impacts, unlike the earlier where there was very heavy carnivore involvement meaning humans were hunting," she said. The Neandertals were dominant carnivores by this time.
Now we can ask about hunting strategy. Steele explains she uses a very low tech method: "We have a number of mandibles, so just looking at the eruption of teeth, we can reconstruct ages of animals." Also, reindeer are conveniently sexually dimorphic and because reindeer give birth at a moment in spring (babies are born at once) we can look at eruption of teeth to see if they're hunted. In a specific location, all ages are present, males and females, so it looks like the reindeer herd would have been slowed allowing the humans to hunt more of them.
Bone chemistry
Carbon isotopes tell us about the vegetation in the environment and nitrogen isotopes tell us about the trophic levels. Carnivores have more concentration of nitrogen. Animals that are aquatic even more nitrogen, so we can look at bone chemistry to reconstruct diet. There aren't much indicators of plant remains, but in a Neandertal tooth you see it's heavily etched by roots because of the acid of roots. The bone chemistry data put Neandertals right along the lines of other carnivores. The majority of protein came from meat (although not mentioned in the talk, new findings show they also practiced cannibalism, reported via science writer Carl Zimmer (Twitter: @carlzimmer)).
Hunting technology
How were the Neandertals doing the hunting? It appears they were using thrusting spears. We know this because it's possible to look at stone artifacts to see if they are aerodynamic or more asymetrical and lumpy for a thrusting spear. We can look at the breakage of the tip as well as the butt. In characteristic way we can look at the breakage.
Middle stone age in Africa 285,000
So while Neandertals are doing their thing in Europe, what's going on in Africa? In Africa, we have the middle stone age and humans who were morphologically similar to us. The big discussion in paleoanthropology is, How modern were they? Did they have symbolism? Were they just like us or behave more like Neandertals without as much symbolism?
In the middle stone age we have good evidence of hunting and burning. There was abundant burning. But, within the middle stone age, we see no evidence of consumption of fish. The people seem to be limited in capturing fish and birds, although there were people accessing coastal resources along the southern coast of Africa, eating a number of mollusks. Could mollusks have fueled brain growth and brought with it symbolic behavior? There were also a number of fireplaces. Did fire fuel brain growth (if you ask primatologist Richard Wrangham as I did last February, then the answer is a resounding "yes!")? This is something that requires further research.
Modern humans in Europe
In Europe about 40 to 10 kya, we have Upper Paleolithic with fully modern humans in Europe. They hunted large game similar to Neandertals and with projectile technology unlike Neandertals. People who were just like us in biology and behavior. This is when we see projectiles for the first time. We see the reconstruction of a spear thrower, with an adle addle.
These modern humans then also enjoyed a diverse diet with abundant small game like fish and flying birds. That's quite different than what their Neandertals cousins were doing, and what humans in Africa of the middle-stone age were doing.
We can also see this in the bone chemistry of the Upper Paleolithic humans. There was definitely protein coming in from aquatic sources, per the nitrogen values in the bones. It's also clear from the bone chemistry that modern humans were eating a much more diverse diet.
Plant use
Getting back to plant use, just recently in PNAS, an article was published about use of plants in Paleolithic times. Grindstones and pestles were used to grind starch grains, reeds, cattailes and ferns that have underground storage organs (roots). These grindstones pulverized the roots and perhaps made flour out of them. So, this is it, the diversity of diet that spread from Africa about 50 kya, and support for the hypothesis that humans replaced Neandertals because of flexibility of diet. Is this what allowed humans to be more successful?
Intensification of resource extraction, including agriculture
Bringing us into more recent time period to complete the story, 50kya humans colonized Europe and Asia and Australia. At around 15kya, they colonized the new world. So, by 10kya we have humans everywheere by 10kya other than Pacific islands and Antarctica. Diet tends to evolve and change. Humans don't stay focused on large game, and birds and fish. They intensify. What we see with intensification in the Holocene is the use of technology to extract nutrients from resources.
Steele shows pictures of mussel shells having accumulated over a short period of time. There was a heavier investment in technology. This creates a stable food supply that allows populations to grow. "We can see this in our local California native indians," she said. Just to highlight investment in technology, she shows slides on the natives' use of technology. "These are all the steps to take acorns and make it into something consumable. They're toxic, so you have to dry them, pulverize and leach them. It requires very heavy technological input."
The intensification brings with it the origins of agriculture at 10 kya. At 10kya we see changes in environment tha promote plant resources, a shift in global climate where there's more CO2, a more wet and stable environment, more admittable to plant production. People are becoming more dependent on smaller resources from agriculture. The fish, they help populations to grow and hunter-gatherer populations are more stable. It's clear from her slide that because of agriculture, there's an uptick in human population growth. Then, when industrialized agriculture arrives, there's an inflection point when we see a high rate of population growth. That's where we are today in the evolution of human diets. That's 4 million years (in 40 minutes).
Question 1: Why did humans replaced Neandertals?
The first question posed to Steele after her talk was about her thoughts were about why humans replaced Neandertals. She answered, "Yes, I think ultimately it's due to dietary differences." There's not much differences in species hunted, not so different butchery, but you do see a difference in stone artifacts and projectile points. The modern human tools were more reliable and accurate. They would've been able to obtain a larger number of reindeer, and been more consistent in hunting, along with having a more diverse diet.
The more ultimate explanation, however, was if it was cultural. Did modern humans have a more complex language? Could symbolism have allowed us to communicate in a more effective way, made our hunting more effective, that's where we're going now with the research. Language is fundamental, so if we can track where language evolved, then we'll find more answers?
Question 2: What conclusive evidence is there of cut marks?
The question asked to Steele reverted back 3.2 mya to how solid the evidence was of Australopithecus afarensis making cut marks. Steele answers that the cut marks are just as conclusive as later time periods. "If we are going to accept the later cut marks, then we have to accept the earlier," she said. "For me they're fine in terms of more recent assemblages. The challenge is to find more cut marks to see if it was widespread or a one-time thing. Who made them? Where are the stone tools?" That's the next project.
Question 3: What ratio of fatty acids in diet correspond to brain size?
Lastly, an audience member asked if recent work on long-chain omega-3s on mood disorders supports the theory that omega-3s from aquatic resources fueled brain growth. The quiestoner also mentions work by others on omega-3 to omega-6 ratios, which has changed since huntergatherer times (from 1:1-3 to 1:10 to 1:20). Could this be the reason that brain sizes are getting smaller?
Steele answers that, in general, there's body size reduction and brain size reduction. Hunter-gatherers of the anthropological record were quite robust. Now we see decrease in stature, brain size reducing, body size reducing. The change in body shape may be due to changes in diet. Whether it's omega-3/omega-6? Steele says she couldn't say for sure if that's the case.
(Note: Hat tip to @KeithNorris and @evolvify (see blog post here) for first alerting me to this new video via their tweets).
I found her talk fascinating, especially because I've been highly interested in how the use of fire and aquatic animals may have played a part in fueling human brain growth, so I ended up taking copious notes. I should note that there isn't anything new presented here, but Steele is excellent at presenting the chronology. If you don't have an hour to watch, then just see my notes below chapter by chapter from "Australopithecus to agriculture."
Human diet is unique among apes
Steele finds that diet is central to her research. "If we want to live, we have to eat," she says. Food is what ultimately supports demographic populations. One thing that is unique about humans in comparison to other apes is a long childhood, a long learning period, that is required for acquiring the knowledge necessary to become successful foragers in a wide environment. After all, humans have exploited almost every nutrient resource in their short time on the Earth.
Another unique thing is how much meat we consume. A large portion of our calories comes from meat. Unlike chimpanzees, who eat the most meat among apes, human eat about 10 times more, Steele said. And we eat animals that are usually larger than us like wildebeasts, reindeer, and mammoths. Steele shows a graph comparing chimp diets to that of tropical hunter gatherers groups, who typically eat little meat. Other hunter-gatherers of the North like the Inuit eat a diet almost entirely of meat. In general, humans specialize in acquiring nutrient-dense foods meats, tubers, and nuts, while chimps select non-nutrient dense like leaves that are more easily collected.
Research themes
When did these differences evolve? Steele presents us with her research themes, which include the following:
- Meat eating. We are consuming animals that are larger than ourselves like wildebeast, reindeer, horses, and so on. Chimpanzees hunt for colobus monkeys, birds, and small amphibians. So when did meat eating appear and when did the transition occur to eating animals larger than us?
- Hunting technology. What technology did humans use to acquire large animals? Spears, bows and arrows, projectile technology? These are complex, so they can represent greater cognition. When did they occur?
- Intensification of resource use, including agriculture. This happened much more recently.
What methods does Steele use to construct ancient human diets? She says that zooarchaeology and tool analyses gives us a window into ancient demographies. There are stone, bone and antler tools. And, on occasion, organic wood and plant tools are preserved. Also, biological anthropology helps tell us more such as skeletal morphology and bone chemistry.
Lucy's diet
Steele introduces the diet of Lucy's species first, Austrolopithecus afarensis of 3.7-2.8 mya, who ate a flexible diet suitable for a variety of habitats.
The skeletal biomechanics and dental structure suggest they ate mostly soft fruits and occasional hard seeds. However, Steele says we assume that they may have eaten some meat because chimps eat meat, but it's unclear just how much.
She points out that, recently, there was a groundbreaking discovery published in Nature (and reported in Scientific American by the science writer Kate Wong (Twitter: @katewong) ) of cut-marked bones in Dikika, Ethiopia suggesting Lucy's species even used stone tools for eating meat.
"This has opened up a window," Steele says for more research, especially in the possibility of stone tool use for extracting nutrients from carcasses of smaller animals. It's worth noting that no stone artifacts were found associated with the cut-marked bones (paleoanthropologist John Hawks (Twitter: @johnhawks) has written more about this topic on his blog).
Cut-marked bones 2.5 million years ago
Typically, a discussion of human diet begins at about 2.5 mya when there is an abundance of cut-marked bones (such as the jaw of a wildebeest) and percussion marks from marrow extraction. Marrow has been an important human resource for nutrients up until modern times because it's high in fat, high in calories.
There is also evidence of Oldowan artifacts (hominin stone tools) available so we know what they were using to get to the marrow.
Then, at about 1.8 mya there are a lot more assemblages, more stone tools, as found in Olduvai Gorge, Tanzania, by Mary Leaky. There are also lots of large bodies bovids and carnivores on the landscape. Steele asks, How did these ancient hominids acquire these large carcasses? Is it conceivable that they could've brought down a wildebeast with just tools?
This is where we get into a discussion of scavenging versus hunting, she said. A related discussion is what percentage of the diet was meat-based versus plant-based. Also, were these ancient hominins practicing passive scavenging getting to a carcass to get the last scraps of meat or breaking open bones for marrow. Or was it active scavenging, chasing off carnivores?
These are all active areas of research. For answers, researchers look in locations of lakeside margins. Bovids came to drink, carnivores know this, we look into these locations to try and reconstruct the foraging.
Aquatic animals
Published recently in the springtime, was a paper suggesting that 1.9 mya in East Turkana, there's evidence of Oldowan foraging of carcasses of aquatic animals like crocodiles and turtles. Steele shows a cut marks on a toe bone of a croc, turtle shells and catfish bones.
"For the first time, we see exploitation of aquatic resources highlighting the diversity of diet. Hominins are very opportunistic, exploiting whatever was available," Steele said.
"This also raises a challenge as with cut-marked bones with Dekika, to try to see if there are cut-marks on similar bones," Steele explains. "The small animal component has been overlooked so we may need to look closer."
Steele also discusses another interesting aspect of using aquatic resources (which will interest any nutritionist like myself). The aquatic resources would have been an easier way to access long-chain omega-3 fatty acids, which are also present in organ meats and brain tissues of large animals.
"The long-chain unsaturated fatty acids are needed for brain growth," she explained. "At this time period we do see an expansion of brain sizes, so perhaps there's a relationship here. We need more data, more examples where we see brain expansion with this kind of diet."
Archeulean hunting and scavenging
Moving more recently in time, we see Homo erectus, hominins of larger body size, and who were first to populate Eurasia 1.6 mya to 285 kya. Were they hunting or actively scavenging? This is unclear, but earlier in Archeulan, we see evolution of technology.
Tear-drop shaped hand axes appear and body size changes. The humans are obviously living in social groups. An illustration she uses takes the liberty of showing piles of plant remains used to make wooden spears. The plant use is unknown.
There are a large number of animal bones with few cut marks. So, the question remains, were hominins still minor players as carnivores, simply cutting off limbs and eating elsewhere. The challenge is finding places away from water sites such as in caves.
Also, we start asking questions about use of fire at this time period.
Wood spears
At around 400 kya, Steele shares that there are one or two examples of exceptional preservation of organic materials such as wooden spears (survived in an oxygen-poor environments from marshes of Germany). They are more likely to be thrusting spears. They have been fire-hardened, sharpened, so it indicates use of fire.
Fire is really useful for warmth, protection from predators, for cooking and cooking really changes the nature of food. It helps make inedible foods edible, releases nutrients for our digestive systems. But fire doesn't preserve well.
The earliest known site where fire is documented is in Israel, dated to 780 kya. "We have an indicator of fire use and plant remains. They're preserve better once charred in archaeological sites," Steele says. "We don't find it common until about 300,000 years ago." This is between Oldowan and modern behavior in the Archeulian.
Neandertals
About 200 kya came the Neandertals and they were competent hunters and manufacturers of stone tools. Interestingly, despite these complex behaviors, they did not have as long a childhood. The Neandertals were able to pick up their abilities pretty early in life.
As part of her post-doc in Germany at Max Plank Institute, Steele worked with identifying species in archaeological sites where Neandertals hunted reindeer and bison. She showed antlers, elbows of reindeer fractured for extracting marrow, and examples of bones in discard piles due to little meat.
"We also see very little carnivore involvement and abundant human impacts, unlike the earlier where there was very heavy carnivore involvement meaning humans were hunting," she said. The Neandertals were dominant carnivores by this time.
Now we can ask about hunting strategy. Steele explains she uses a very low tech method: "We have a number of mandibles, so just looking at the eruption of teeth, we can reconstruct ages of animals." Also, reindeer are conveniently sexually dimorphic and because reindeer give birth at a moment in spring (babies are born at once) we can look at eruption of teeth to see if they're hunted. In a specific location, all ages are present, males and females, so it looks like the reindeer herd would have been slowed allowing the humans to hunt more of them.
Bone chemistry
Carbon isotopes tell us about the vegetation in the environment and nitrogen isotopes tell us about the trophic levels. Carnivores have more concentration of nitrogen. Animals that are aquatic even more nitrogen, so we can look at bone chemistry to reconstruct diet. There aren't much indicators of plant remains, but in a Neandertal tooth you see it's heavily etched by roots because of the acid of roots. The bone chemistry data put Neandertals right along the lines of other carnivores. The majority of protein came from meat (although not mentioned in the talk, new findings show they also practiced cannibalism, reported via science writer Carl Zimmer (Twitter: @carlzimmer)).
Hunting technology
How were the Neandertals doing the hunting? It appears they were using thrusting spears. We know this because it's possible to look at stone artifacts to see if they are aerodynamic or more asymetrical and lumpy for a thrusting spear. We can look at the breakage of the tip as well as the butt. In characteristic way we can look at the breakage.
Middle stone age in Africa 285,000
So while Neandertals are doing their thing in Europe, what's going on in Africa? In Africa, we have the middle stone age and humans who were morphologically similar to us. The big discussion in paleoanthropology is, How modern were they? Did they have symbolism? Were they just like us or behave more like Neandertals without as much symbolism?
In the middle stone age we have good evidence of hunting and burning. There was abundant burning. But, within the middle stone age, we see no evidence of consumption of fish. The people seem to be limited in capturing fish and birds, although there were people accessing coastal resources along the southern coast of Africa, eating a number of mollusks. Could mollusks have fueled brain growth and brought with it symbolic behavior? There were also a number of fireplaces. Did fire fuel brain growth (if you ask primatologist Richard Wrangham as I did last February, then the answer is a resounding "yes!")? This is something that requires further research.
Modern humans in Europe
In Europe about 40 to 10 kya, we have Upper Paleolithic with fully modern humans in Europe. They hunted large game similar to Neandertals and with projectile technology unlike Neandertals. People who were just like us in biology and behavior. This is when we see projectiles for the first time. We see the reconstruction of a spear thrower, with an adle addle.
These modern humans then also enjoyed a diverse diet with abundant small game like fish and flying birds. That's quite different than what their Neandertals cousins were doing, and what humans in Africa of the middle-stone age were doing.
We can also see this in the bone chemistry of the Upper Paleolithic humans. There was definitely protein coming in from aquatic sources, per the nitrogen values in the bones. It's also clear from the bone chemistry that modern humans were eating a much more diverse diet.
Plant use
Getting back to plant use, just recently in PNAS, an article was published about use of plants in Paleolithic times. Grindstones and pestles were used to grind starch grains, reeds, cattailes and ferns that have underground storage organs (roots). These grindstones pulverized the roots and perhaps made flour out of them. So, this is it, the diversity of diet that spread from Africa about 50 kya, and support for the hypothesis that humans replaced Neandertals because of flexibility of diet. Is this what allowed humans to be more successful?
Intensification of resource extraction, including agriculture
Bringing us into more recent time period to complete the story, 50kya humans colonized Europe and Asia and Australia. At around 15kya, they colonized the new world. So, by 10kya we have humans everywheere by 10kya other than Pacific islands and Antarctica. Diet tends to evolve and change. Humans don't stay focused on large game, and birds and fish. They intensify. What we see with intensification in the Holocene is the use of technology to extract nutrients from resources.
Steele shows pictures of mussel shells having accumulated over a short period of time. There was a heavier investment in technology. This creates a stable food supply that allows populations to grow. "We can see this in our local California native indians," she said. Just to highlight investment in technology, she shows slides on the natives' use of technology. "These are all the steps to take acorns and make it into something consumable. They're toxic, so you have to dry them, pulverize and leach them. It requires very heavy technological input."
The intensification brings with it the origins of agriculture at 10 kya. At 10kya we see changes in environment tha promote plant resources, a shift in global climate where there's more CO2, a more wet and stable environment, more admittable to plant production. People are becoming more dependent on smaller resources from agriculture. The fish, they help populations to grow and hunter-gatherer populations are more stable. It's clear from her slide that because of agriculture, there's an uptick in human population growth. Then, when industrialized agriculture arrives, there's an inflection point when we see a high rate of population growth. That's where we are today in the evolution of human diets. That's 4 million years (in 40 minutes).
Question 1: Why did humans replaced Neandertals?
The first question posed to Steele after her talk was about her thoughts were about why humans replaced Neandertals. She answered, "Yes, I think ultimately it's due to dietary differences." There's not much differences in species hunted, not so different butchery, but you do see a difference in stone artifacts and projectile points. The modern human tools were more reliable and accurate. They would've been able to obtain a larger number of reindeer, and been more consistent in hunting, along with having a more diverse diet.
The more ultimate explanation, however, was if it was cultural. Did modern humans have a more complex language? Could symbolism have allowed us to communicate in a more effective way, made our hunting more effective, that's where we're going now with the research. Language is fundamental, so if we can track where language evolved, then we'll find more answers?
Question 2: What conclusive evidence is there of cut marks?
The question asked to Steele reverted back 3.2 mya to how solid the evidence was of Australopithecus afarensis making cut marks. Steele answers that the cut marks are just as conclusive as later time periods. "If we are going to accept the later cut marks, then we have to accept the earlier," she said. "For me they're fine in terms of more recent assemblages. The challenge is to find more cut marks to see if it was widespread or a one-time thing. Who made them? Where are the stone tools?" That's the next project.
Question 3: What ratio of fatty acids in diet correspond to brain size?
Lastly, an audience member asked if recent work on long-chain omega-3s on mood disorders supports the theory that omega-3s from aquatic resources fueled brain growth. The quiestoner also mentions work by others on omega-3 to omega-6 ratios, which has changed since huntergatherer times (from 1:1-3 to 1:10 to 1:20). Could this be the reason that brain sizes are getting smaller?
Steele answers that, in general, there's body size reduction and brain size reduction. Hunter-gatherers of the anthropological record were quite robust. Now we see decrease in stature, brain size reducing, body size reducing. The change in body shape may be due to changes in diet. Whether it's omega-3/omega-6? Steele says she couldn't say for sure if that's the case.
(Note: Hat tip to @KeithNorris and @evolvify (see blog post here) for first alerting me to this new video via their tweets).
Labels:
evolution,
Evolving Health,
omega-3
38 g of sardines or 2 fish oil softgels? Let us look at the numbers
The bar chart below shows the fat content of 1 sardine (38 g) canned in tomato sauce, and 2 fish oil softgels of the Nature Made brand. (The sardine is about 1/3 of the content of a typical can, and the data is from Nutritiondata.com. The two softgels are listed as the “serving size” on the Nature Made bottle.) Both the sardine and softgels have some vegetable oil added; presumably to increase their vitamin E content and form a more stable oil mix. This chart is a good reminder that looking at actual numbers can be quite instructive sometimes. Even though the chart focuses on fat content, it is worth noting that the 38 g sardine also contains 8 g of high quality protein.
If your goal with the fish oil is to “neutralize” the omega-6 fat content of your diet, which is most people’s main goal, you should consider this. A rough measure of the omega-6 neutralization “power” of a food portion is, by definition, its omega-3 minus omega-6 content. For the 1 canned sardine, this difference is 596 mg; for the 2 fish oil softgels, 440 mg. The reason is that the two softgels have more omega-6 than the sardine.
In case you are wondering, the canning process does not seem to have much of an effect on the nutrient composition of the sardine. There is some research suggesting that adding vegetable oil (e.g., soy) helps preserve the omega-3 content during the canning process. There is also research suggesting that not much is lost even without any vegetable oil being added.
Fish oil softgels, when taken in moderation (e.g., two of the type discussed in this post, per day), are probably okay as “neutralizers” of omega-6 fats in the diet, and sources of a minimum amount of omega-3 fats for those who do not like seafood. For those who can consume 1 canned sardine per day, which is only 1/3 of a typical can of sardines, the sardine is not only a more effective source of omega-3, but also a good source of protein and many other nutrients.
As far as balancing dietary omega-6 fats is concerned, you are much better off reducing your consumption of foods rich in omega-6 fats in the first place. Apparently nothing beats avoiding industrial seed oils in that respect. It is also advisable to eat certain types of nuts with high omega-6 content, like walnuts, in moderation.
Both omega-6 and omega-3 fats are essential; they must be part of one’s diet. The actual minimum required amounts are fairly small, probably much lower than the officially recommended amounts. Chances are they would be met by anyone on a balanced diet of whole foods. Too much of either type of fat in synthetic or industrialized form can cause problems. A couple of instructive posts on this topic are this post by Chris Masterjohn, and this one by Chris Kresser.
Even if you don’t like canned sardines, it is not much harder to gulp down 38 g of sardines than it is to gulp down 2 fish oil softgels. You can get the fish oil for $12 per bottle with 300 softgels; or 8 cents per serving. You can get a can of sardines for 50 cents; which gives 16.6 cents per serving. The sardine is twice as expensive, but carries a lot more nutritional value.
You can also buy wild caught sardines, like I do. I also eat canned sardines. Wild caught sardines cost about $2 per lb, and are among the least expensive fish variety. They are not difficult to prepare; see this post for a recipe.
I don’t know how many sardines go into the industrial process of making 2 fish oil softgels, but I suspect that it is more than one. So it is also probably more ecologically sound to eat the sardine.
If your goal with the fish oil is to “neutralize” the omega-6 fat content of your diet, which is most people’s main goal, you should consider this. A rough measure of the omega-6 neutralization “power” of a food portion is, by definition, its omega-3 minus omega-6 content. For the 1 canned sardine, this difference is 596 mg; for the 2 fish oil softgels, 440 mg. The reason is that the two softgels have more omega-6 than the sardine.
In case you are wondering, the canning process does not seem to have much of an effect on the nutrient composition of the sardine. There is some research suggesting that adding vegetable oil (e.g., soy) helps preserve the omega-3 content during the canning process. There is also research suggesting that not much is lost even without any vegetable oil being added.
Fish oil softgels, when taken in moderation (e.g., two of the type discussed in this post, per day), are probably okay as “neutralizers” of omega-6 fats in the diet, and sources of a minimum amount of omega-3 fats for those who do not like seafood. For those who can consume 1 canned sardine per day, which is only 1/3 of a typical can of sardines, the sardine is not only a more effective source of omega-3, but also a good source of protein and many other nutrients.
As far as balancing dietary omega-6 fats is concerned, you are much better off reducing your consumption of foods rich in omega-6 fats in the first place. Apparently nothing beats avoiding industrial seed oils in that respect. It is also advisable to eat certain types of nuts with high omega-6 content, like walnuts, in moderation.
Both omega-6 and omega-3 fats are essential; they must be part of one’s diet. The actual minimum required amounts are fairly small, probably much lower than the officially recommended amounts. Chances are they would be met by anyone on a balanced diet of whole foods. Too much of either type of fat in synthetic or industrialized form can cause problems. A couple of instructive posts on this topic are this post by Chris Masterjohn, and this one by Chris Kresser.
Even if you don’t like canned sardines, it is not much harder to gulp down 38 g of sardines than it is to gulp down 2 fish oil softgels. You can get the fish oil for $12 per bottle with 300 softgels; or 8 cents per serving. You can get a can of sardines for 50 cents; which gives 16.6 cents per serving. The sardine is twice as expensive, but carries a lot more nutritional value.
You can also buy wild caught sardines, like I do. I also eat canned sardines. Wild caught sardines cost about $2 per lb, and are among the least expensive fish variety. They are not difficult to prepare; see this post for a recipe.
I don’t know how many sardines go into the industrial process of making 2 fish oil softgels, but I suspect that it is more than one. So it is also probably more ecologically sound to eat the sardine.
Monday, December 20, 2010
Nuts by numbers: Should you eat them, and how much?
Nuts are generally seen as good sources of protein and magnesium. The latter plays a number of roles in the human body, and is considered critical for bone health. Nuts are also believed to be good sources of vitamin E. While there is a lot of debate about vitamin E’s role in health, it is considered by many to be a powerful antioxidant. Other than in nuts, vitamin E is not easily found in foods other than seeds and seed oils.
Some of the foods that we call nuts are actually seeds; others are legumes. For simplification, in this post I am calling nuts those foods that are generally protected by shells (some harder than others). This protective layer is what makes most people call them nuts.
Let us see how different nuts stack up against each other in terms of key nutrients. The quantities listed below are per 1 oz (28 g), and are based on data from Nutritiondata.com. All are raw. Roasting tends to reduce the vitamin content of nuts, often by half, and has little effect on the mineral content. Protein and fat content are also reduced, but not as much as the vitamin content.
These two figures show the protein, fat, and carbohydrate content of nuts (on the left); and the omega-6 and omega-3 fat content (on the right).
When we talk about nuts, walnuts are frequently presented in a very positive light. The reason normally given is that walnuts have a high omega-3 content; the plant form of omega-3, alpha-linolenic acid (ALA). That is true. But look at the large amount of omega-6 in walnuts. The difference between the omega-6 and omega-3 content in walnuts is about 8 g! And this is in only 1 oz of walnuts. That is 8 g of possibly pro-inflammatory omega-6 fats to be “neutralized”. It would take many fish oil softgels to achieve that.
Walnuts should be eaten in moderation. Most studies looking at the health effects of nuts, including walnuts, show positive results in short-term interventions. But they usually involve moderate consumption, often of 1 oz per day. Eat several ounces of walnuts every day, and you are entering industrial see oil territory in terms of omega-6 fats consumption. Maybe other nutrients in walnuts have protective effects, but still, this looks like dangerous territory; “diseases of civilization” territory.
A side note. Focusing too much on the omega-6 to omega-3 ratio of individual foods can be quite misleading. The reason is that a food with a very small amount of omega-6 (e.g., 50 mg) but close to zero omega-3 will have a very high ratio. (Any number divided by zero yields infinity.) Yet, that food will contribute little omega-6 to a person’s diet. It is the ratio at the end of the day that matters, when all foods that have been eaten are considered.
The figures below show the magnesium content of nuts (on the left); and the vitamin E content (on the right).
Let us say that you are looking for the best combination of protein, magnesium, and vitamin E. And you also want to limit your intake of omega-6 fats, which is a very wise thing to do. Then what is the best choice? It looks like it is almonds. And even they should be eaten in small amounts, as 1 oz has more than 3 g of omega-6 fats.
Macadamia nuts don’t have much omega-6; their fats are mostly monounsaturated, which are very good. Their protein to fat ratio is very low, and they don’t have much magnesium or vitamin E. Coconuts (i.e., their meat) have mostly medium-chain saturated fats, which are also very good. Coconuts have little protein, magnesium, and vitamin E. If you want to increase your intake of healthy fats, both macadamia nuts and coconuts are good choices, with macadamia nuts providing about 3 times more fat.
There are many other dietary sources of magnesium around. In fact, magnesium is found in many foods. Examples are, in approximate descending order of content: salmon, spinach, sardine, cod, halibut, banana, white potato, sweet potato, beef, chicken, pork, liver, and cabbage. This is by no means a comprehensive list.
As for vitamin E, it likes to hide in seeds. While it may be a powerful antioxidant, I wonder whether Mother Nature really had it “in mind” as she tinkered with our DNA for the last few million years.
Some of the foods that we call nuts are actually seeds; others are legumes. For simplification, in this post I am calling nuts those foods that are generally protected by shells (some harder than others). This protective layer is what makes most people call them nuts.
Let us see how different nuts stack up against each other in terms of key nutrients. The quantities listed below are per 1 oz (28 g), and are based on data from Nutritiondata.com. All are raw. Roasting tends to reduce the vitamin content of nuts, often by half, and has little effect on the mineral content. Protein and fat content are also reduced, but not as much as the vitamin content.
These two figures show the protein, fat, and carbohydrate content of nuts (on the left); and the omega-6 and omega-3 fat content (on the right).
When we talk about nuts, walnuts are frequently presented in a very positive light. The reason normally given is that walnuts have a high omega-3 content; the plant form of omega-3, alpha-linolenic acid (ALA). That is true. But look at the large amount of omega-6 in walnuts. The difference between the omega-6 and omega-3 content in walnuts is about 8 g! And this is in only 1 oz of walnuts. That is 8 g of possibly pro-inflammatory omega-6 fats to be “neutralized”. It would take many fish oil softgels to achieve that.
Walnuts should be eaten in moderation. Most studies looking at the health effects of nuts, including walnuts, show positive results in short-term interventions. But they usually involve moderate consumption, often of 1 oz per day. Eat several ounces of walnuts every day, and you are entering industrial see oil territory in terms of omega-6 fats consumption. Maybe other nutrients in walnuts have protective effects, but still, this looks like dangerous territory; “diseases of civilization” territory.
A side note. Focusing too much on the omega-6 to omega-3 ratio of individual foods can be quite misleading. The reason is that a food with a very small amount of omega-6 (e.g., 50 mg) but close to zero omega-3 will have a very high ratio. (Any number divided by zero yields infinity.) Yet, that food will contribute little omega-6 to a person’s diet. It is the ratio at the end of the day that matters, when all foods that have been eaten are considered.
The figures below show the magnesium content of nuts (on the left); and the vitamin E content (on the right).
Let us say that you are looking for the best combination of protein, magnesium, and vitamin E. And you also want to limit your intake of omega-6 fats, which is a very wise thing to do. Then what is the best choice? It looks like it is almonds. And even they should be eaten in small amounts, as 1 oz has more than 3 g of omega-6 fats.
Macadamia nuts don’t have much omega-6; their fats are mostly monounsaturated, which are very good. Their protein to fat ratio is very low, and they don’t have much magnesium or vitamin E. Coconuts (i.e., their meat) have mostly medium-chain saturated fats, which are also very good. Coconuts have little protein, magnesium, and vitamin E. If you want to increase your intake of healthy fats, both macadamia nuts and coconuts are good choices, with macadamia nuts providing about 3 times more fat.
There are many other dietary sources of magnesium around. In fact, magnesium is found in many foods. Examples are, in approximate descending order of content: salmon, spinach, sardine, cod, halibut, banana, white potato, sweet potato, beef, chicken, pork, liver, and cabbage. This is by no means a comprehensive list.
As for vitamin E, it likes to hide in seeds. While it may be a powerful antioxidant, I wonder whether Mother Nature really had it “in mind” as she tinkered with our DNA for the last few million years.
Friday, December 17, 2010
Scottish Mental Health Arts and Film Festival 2011
CALL FOR ENTRIES
Our annual open film submission gives filmmakers the opportunity to share their work and ideas with audiences across Scotland and internationally. The festival is committed to finding and celebrating the work of filmmakers who explore mental health in film. In its broadest sense ‘mental health’ is a term which touches most aspects of our lives; from our relationships to how we respond to the world around us. We’re looking for films which show that mental health is something we all have, and something we all need to prioritise from time to time.
Previous winning submissions have looked at topics such as moving home, ageing, grief, loss, endurance, support, friendship, equality, sport, music, childhood as well as films about specific diagnoses or conditions.
Entry is free. The closing date for entries is Friday 6th May 2011. Please visit the website www.mhfestival.com for more information. Email smhaff@gmail.com for submission guidelines and entry form.
The fifth annual Scottish Mental Health Arts and Film Festival will take place across Scotland throughout October 2011.
Measuring the Value of Culture: a report to the Department for Culture Media and Sport
Dr. Dave O’Brien
The cultural sector faces the conundrum of proving its value in a way that can be understood by decision-makers. Arts and cultural organisations face a ‘cooler climate’ than the one that prevailed during the early 2000s. As a result it will not be enough for arts and culture to resort to claiming to be a unique or special case compared with other government sectors. Since the 1980s the value of the cultural sector has been demonstrated through the lens of ‘impact’, whether economic or social. However in recent years there has been recognition, both within central government and in parts of the publically funded cultural sector, of the need to more clearly articulate the value of culture using methods which fit in with central government’s decision-making. Thus the cultural sector will need to use the tools and concepts of economics to fully state their benefits in the prevailing language of policy appraisal and evaluation.
Full report can be found at:
http://www.culture.gov.uk/publications/7660.aspx
S C E N A R I O S in Arts and Health
Following on from the ongoing M A N I F E S T O events and building on an emerging, shared vision, MMU will be hosting a free event on the 23rd September 2011 to explore where the arts/health agenda is in relation to the ongoing financial downturn; government changes and cuts; and societal shift, to explore our future practice over a generation. Places will be strictly limited to this event and you can register your interest at artsforhealth@mmu.ac.uk (this does not guarantee a place).
Thursday, December 16, 2010
Maknig to mayn tipos? Myabe ur teh boz
Undoubtedly one of the big differences between life today and in our Paleolithic past is the level of stress that modern humans face on a daily basis. Much stress happens at work, which is very different from what our Paleolithic ancestors would call work. Modern office work, in particular, would probably be seen as a form of slavery by our Paleolithic ancestors.
Some recent research suggests that organizational power distance is a big factor in work-related stress. Power distance is essentially the degree to which bosses and subordinates accept wide differences in organizational power between them (Hofstede, 2001).
I have been studying the topic of information overload for a while. It is a fascinating topic. People who experience it have the impression that they have more information to process than they can handle. They also experience significant stress as a result of it, and both the quality of their work and their productivity goes down.
Recently some colleagues and I conducted a study that included employees from companies in New Zealand, Spain, and the USA (Kock, Del Aguila-Obra & Padilla-Meléndez, 2009). These are countries whose organizations typically display significant differences in power distance. We found something unexpected. Information overload was much more strongly associated with power distance than with the actual amount of information employees had to process on a daily basis.
While looking for explanations to this paradoxical finding, I recalled an interview I gave way back in 2001 to the Philadelphia Inquirer, commenting on research by Dr. David A. Owens. His research uncovered an interesting phenomenon. The higher up in the organizational pecking order one was, the less the person was concerned about typos on emails to subordinates.
There is also some cool research by Carlson & Davis (1998) suggesting that bosses tend to pick the communication media that are the most convenient for them, and don’t care much about convenience for the subordinates. One example would be calling a subordinate on the phone to assign a task, and then demanding a detailed follow-up report by email.
As a side note, writing a reasonably sized email takes a lot longer than conveying the same ideas over the phone or face-to-face (Kock, 2005). To be more precise, it takes about 10 times longer when the word count is over 250 and the ideas being conveyed are somewhat complex. For very short messages, a written medium like email is fairly convenient, and the amount of time to convey ideas may be even shorter than by using the phone or doing it face-to-face.
So a picture started to emerge. Bosses choose the communication media that are convenient for them when dealing with subordinates. If the media are written, they don’t care about typos at all. The subordinates use the media that are imposed on them, and if the media are written they certainly don’t want something with typos coming from them to reach their bosses. It would make them look bad.
The final result is this. Subordinates experience significant information overload, particularly in high power distance organizations. They also experience significant stress. Work quality and productivity goes down, and they get even more stressed. They get fat, or sickly thin. Their health deteriorates. Eventually they get fired, which doesn’t help a bit.
What should you do, if you are not the boss? Here are some suggestions:
- Try to tactfully avoid letting communication media being imposed on you all the time by your boss (and others). Explicitly state, in a polite way, the media that would be most convenient for you in various circusmtances, both as a receiver and sender. Generally, media that support oral speech are better for discussing complex ideas. Written media are better for short exchanges. Want an evolutionary reason for that? As you wish: Kock (2004).
- Discuss the ideas in this post with your boss; assuming that the person cares. Perhaps there is something that can be done to reduce power distance, for example. Making the work environment more democratic seems to help in some cases.
- And ... dot’n wrory soo mach aobut tipos ... which could be extrapolated to: don’t sweat the small stuff. Most bosses really care about results, and will gladly take an email with some typos telling them that a new customer signed a contract. They will not be as happy with an email telling them the opposite, no matter how well written it is.
Otherwise, your organizational demise may come sooner than you think.
References
Carlson, P.J., & Davis, G.B. (1998). An investigation of media selection among directors and managers: From "self" to "other" orientation. MIS Quarterly, 22(3), 335-362.
Hofstede, G. (2001). Culture’s consequences: Comparing values, behaviors, institutions, and organizations across nations. Thousand Oaks, CA: Sage.
Kock, N. (2004). The psychobiological model: Towards a new theory of computer-mediated communication based on Darwinian evolution. Organization Science, 15(3), 327-348.
Kock, N. (2005). Business process improvement through e-collaboration: Knowledge sharing through the use of virtual groups. Hershey, PA: Idea Group Publishing.
Kock, N., Del Aguila-Obra, A.R., & Padilla-Meléndez, A. (2009). The information overload paradox: A structural equation modeling analysis of data from New Zealand, Spain and the U.S.A. Journal of Global Information Management, 17(3), 1-17.
Some recent research suggests that organizational power distance is a big factor in work-related stress. Power distance is essentially the degree to which bosses and subordinates accept wide differences in organizational power between them (Hofstede, 2001).
(Source: talentedapps.wordpress.com)
I have been studying the topic of information overload for a while. It is a fascinating topic. People who experience it have the impression that they have more information to process than they can handle. They also experience significant stress as a result of it, and both the quality of their work and their productivity goes down.
Recently some colleagues and I conducted a study that included employees from companies in New Zealand, Spain, and the USA (Kock, Del Aguila-Obra & Padilla-Meléndez, 2009). These are countries whose organizations typically display significant differences in power distance. We found something unexpected. Information overload was much more strongly associated with power distance than with the actual amount of information employees had to process on a daily basis.
While looking for explanations to this paradoxical finding, I recalled an interview I gave way back in 2001 to the Philadelphia Inquirer, commenting on research by Dr. David A. Owens. His research uncovered an interesting phenomenon. The higher up in the organizational pecking order one was, the less the person was concerned about typos on emails to subordinates.
There is also some cool research by Carlson & Davis (1998) suggesting that bosses tend to pick the communication media that are the most convenient for them, and don’t care much about convenience for the subordinates. One example would be calling a subordinate on the phone to assign a task, and then demanding a detailed follow-up report by email.
As a side note, writing a reasonably sized email takes a lot longer than conveying the same ideas over the phone or face-to-face (Kock, 2005). To be more precise, it takes about 10 times longer when the word count is over 250 and the ideas being conveyed are somewhat complex. For very short messages, a written medium like email is fairly convenient, and the amount of time to convey ideas may be even shorter than by using the phone or doing it face-to-face.
So a picture started to emerge. Bosses choose the communication media that are convenient for them when dealing with subordinates. If the media are written, they don’t care about typos at all. The subordinates use the media that are imposed on them, and if the media are written they certainly don’t want something with typos coming from them to reach their bosses. It would make them look bad.
The final result is this. Subordinates experience significant information overload, particularly in high power distance organizations. They also experience significant stress. Work quality and productivity goes down, and they get even more stressed. They get fat, or sickly thin. Their health deteriorates. Eventually they get fired, which doesn’t help a bit.
What should you do, if you are not the boss? Here are some suggestions:
- Try to tactfully avoid letting communication media being imposed on you all the time by your boss (and others). Explicitly state, in a polite way, the media that would be most convenient for you in various circusmtances, both as a receiver and sender. Generally, media that support oral speech are better for discussing complex ideas. Written media are better for short exchanges. Want an evolutionary reason for that? As you wish: Kock (2004).
- Discuss the ideas in this post with your boss; assuming that the person cares. Perhaps there is something that can be done to reduce power distance, for example. Making the work environment more democratic seems to help in some cases.
- And ... dot’n wrory soo mach aobut tipos ... which could be extrapolated to: don’t sweat the small stuff. Most bosses really care about results, and will gladly take an email with some typos telling them that a new customer signed a contract. They will not be as happy with an email telling them the opposite, no matter how well written it is.
Otherwise, your organizational demise may come sooner than you think.
References
Carlson, P.J., & Davis, G.B. (1998). An investigation of media selection among directors and managers: From "self" to "other" orientation. MIS Quarterly, 22(3), 335-362.
Hofstede, G. (2001). Culture’s consequences: Comparing values, behaviors, institutions, and organizations across nations. Thousand Oaks, CA: Sage.
Kock, N. (2004). The psychobiological model: Towards a new theory of computer-mediated communication based on Darwinian evolution. Organization Science, 15(3), 327-348.
Kock, N. (2005). Business process improvement through e-collaboration: Knowledge sharing through the use of virtual groups. Hershey, PA: Idea Group Publishing.
Kock, N., Del Aguila-Obra, A.R., & Padilla-Meléndez, A. (2009). The information overload paradox: A structural equation modeling analysis of data from New Zealand, Spain and the U.S.A. Journal of Global Information Management, 17(3), 1-17.
Monday, December 13, 2010
What is a reasonable vitamin D level?
The figure and table below are from Vieth (1999); one of the most widely cited articles on vitamin D. The figure shows the gradual increase in blood concentrations of 25-Hydroxyvitamin, or 25(OH)D, following the start of daily vitamin D3 supplementation of 10,000 IU/day. The table shows the average levels for people living and/or working in sun-rich environments; vitamin D3 is produced by the skin based on sun exposure.
25(OH)D is also referred to as calcidiol. It is a pre-hormone that is produced by the liver based on vitamin D3. To convert from nmol/L to ng/mL, divide by 2.496. The figure suggests that levels start to plateau at around 1 month after the beginning of supplementation, reaching a point of saturation after 2-3 months. Without supplementation or sunlight exposure, levels should go down at a comparable rate. The maximum average level shown on the table is 163 nmol/L (65 ng/mL), and refers to a sample of lifeguards.
From the figure we can infer that people on average will plateau at approximately 130 nmol/L, after months of 10,000 IU/d supplementation. That is 52 ng/mL. Assuming a normal distribution with a standard deviation of about 20 percent of the range of average levels, we can expect about 68 percent of the population to be in the 42 to 63 ng/mL range.
This might be the range most of us should expect to be in at an intake of 10,000 IU/d. This is the equivalent to the body’s own natural production through sun exposure.
Approximately 32 percent of the population can be expected to be outside this range. A person who is two standard deviations (SDs) above the mean (i.e., average) would be at around 73 ng/mL. Three SDs above the mean would be 83 ng/mL. Two SDs below the mean would be 31 ng/mL.
There are other factors that may affect levels. For example, being overweight tends to reduce them. Excess cortisol production, from stress, may also reduce them.
Supplementing beyond 10,000 IU/d to reach levels much higher than those in the range of 42 to 63 ng/mL may not be optimal. Interestingly, one cannot overdose through sun exposure, and the idea that people do not produce vitamin D3 after 40 years of age is a myth.
One would be taking in about 14,000 IU/d of vitamin D3 by combining sun exposure with a supplemental dose of 4,000 IU/d. Clear signs of toxicity may not occur until one reaches 50,000 IU/d. Still, one may develop other complications, such as kidney stones, at levels significantly above 10,000 IU/d.
See this post by Chris Masterjohn, which makes a different argument, but with somewhat similar conclusions. Chris points out that there is a point of saturation above which the liver is unable to properly hydroxylate vitamin D3 to produce 25(OH)D.
How likely it is that a person will develop complications like kidney stones at levels above 10,000 IU/d, and what the danger threshold level could be, are hard to guess. Kidney stone incidence is a sensitive measure of possible problems; but it is, by itself, an unreliable measure. The reason is that it is caused by factors that are correlated with high levels of vitamin D, where those levels may not be the problem.
There is some evidence that kidney stones are associated with living in sunny regions. This is not, in my view, due to high levels of vitamin D3 production from sunlight. Kidney stones are also associated with chronic dehydration, and populations living in sunny regions may be at a higher than average risk of chronic dehydration. This is particularly true for sunny regions that are also very hot and/or dry.
Reference
Vieth, R. (1999). Vitamin D supplementation, 25-hydroxyvitamin D concentrations, and safety. American Journal of Clinical Nutrition, 69(5), 842-856.
25(OH)D is also referred to as calcidiol. It is a pre-hormone that is produced by the liver based on vitamin D3. To convert from nmol/L to ng/mL, divide by 2.496. The figure suggests that levels start to plateau at around 1 month after the beginning of supplementation, reaching a point of saturation after 2-3 months. Without supplementation or sunlight exposure, levels should go down at a comparable rate. The maximum average level shown on the table is 163 nmol/L (65 ng/mL), and refers to a sample of lifeguards.
From the figure we can infer that people on average will plateau at approximately 130 nmol/L, after months of 10,000 IU/d supplementation. That is 52 ng/mL. Assuming a normal distribution with a standard deviation of about 20 percent of the range of average levels, we can expect about 68 percent of the population to be in the 42 to 63 ng/mL range.
This might be the range most of us should expect to be in at an intake of 10,000 IU/d. This is the equivalent to the body’s own natural production through sun exposure.
Approximately 32 percent of the population can be expected to be outside this range. A person who is two standard deviations (SDs) above the mean (i.e., average) would be at around 73 ng/mL. Three SDs above the mean would be 83 ng/mL. Two SDs below the mean would be 31 ng/mL.
There are other factors that may affect levels. For example, being overweight tends to reduce them. Excess cortisol production, from stress, may also reduce them.
Supplementing beyond 10,000 IU/d to reach levels much higher than those in the range of 42 to 63 ng/mL may not be optimal. Interestingly, one cannot overdose through sun exposure, and the idea that people do not produce vitamin D3 after 40 years of age is a myth.
One would be taking in about 14,000 IU/d of vitamin D3 by combining sun exposure with a supplemental dose of 4,000 IU/d. Clear signs of toxicity may not occur until one reaches 50,000 IU/d. Still, one may develop other complications, such as kidney stones, at levels significantly above 10,000 IU/d.
See this post by Chris Masterjohn, which makes a different argument, but with somewhat similar conclusions. Chris points out that there is a point of saturation above which the liver is unable to properly hydroxylate vitamin D3 to produce 25(OH)D.
How likely it is that a person will develop complications like kidney stones at levels above 10,000 IU/d, and what the danger threshold level could be, are hard to guess. Kidney stone incidence is a sensitive measure of possible problems; but it is, by itself, an unreliable measure. The reason is that it is caused by factors that are correlated with high levels of vitamin D, where those levels may not be the problem.
There is some evidence that kidney stones are associated with living in sunny regions. This is not, in my view, due to high levels of vitamin D3 production from sunlight. Kidney stones are also associated with chronic dehydration, and populations living in sunny regions may be at a higher than average risk of chronic dehydration. This is particularly true for sunny regions that are also very hot and/or dry.
Reference
Vieth, R. (1999). Vitamin D supplementation, 25-hydroxyvitamin D concentrations, and safety. American Journal of Clinical Nutrition, 69(5), 842-856.
Saturday, December 11, 2010
Strength training: A note about Scooby and comments by Anon
Let me start this post with a note about Scooby, who is a massive bodybuilder who has a great website with tips on how to exercise at home without getting injured. Scooby is probably as massive a bodybuilder as anyone can get naturally, and very lean. He says he is a natural bodybuilder, and I am inclined to believe him. His dietary advice is “old school” and would drive many of the readers of this blog crazy – e.g., plenty of grains, and six meals a day. But it obviously works for him. (As far as muscle gain is concerned, a lot of different approaches work. For some people, almost any reasonable approach will work; especially if they are young men with high testosterone levels.)
The text below is all from an anonymous commenter’s notes on this post discussing the theory of supercompensation. Many thanks to this person for the detailed and thoughtful comment, which is a good follow-up on the note above about Scooby. In fact I thought that the comment might have been from Scooby; but I don’t think so. My additions are within “[ ]”. While the comment is there under the previous post for everyone to see, I thought that it deserved a separate post.
I love this subject [i.e., strength training]. No shortages of opinions backed by research with the one disconcerting detail that they don't agree.
First one opening general statement. If there was one right way we'd all know it by now and we'd all be doing it. People's bodies are different and what motivates them is different. (Motivation matters as a variable.)
My view on one set vs. three is based on understanding what you're measuring and what you're after in a training result.
Most studies look at one rep max strength gains as the metric but three sets [of repetitions] improves strength/endurance. People need strength/endurance more typically than they need maximal strength in their daily living. The question here becomes what is your goal?
The next thing I look at in training is neural adaptation. Not from the point of view of simple muscle strength gain but from the point of view of coordinated muscle function, again, something that is transferable to real life. When you exercise the brain is always learning what it is you are asking it to do. What you need to ask yourself is how well does this exercise correlate with a real life requirements.
[This topic needs a separate post, but one can reasonably argue that your brain works a lot harder during a one-hour strength training session than during a one-hour session in which you are solving a difficult mathematical problem.]
To this end single legged squats are vastly superior to double legged squats. They invoke balance and provoke the activation of not only the primary movers but the stabilization muscles as well. The brain is acquiring a functional skill in activating all these muscles in proper harmony and improving balance.
I also like walking lunges at the climbing wall in the gym (when not in use, of course) as the instability of the soft foam at the base of the wall gives an excellent boost to the basic skill by ramping up the important balance/stabilization component (vestibular/stabilization muscles). The stabilization muscles protect joints (inner unit vs. outer unit).
The balance and single leg components also increase core activation naturally. (See single legged squat and quadratus lumborum for instance.) [For more on the quadratus lumborum muscle, see here.]
Both [of] these exercises can be done with dumbbells for increased strength[;] and though leg exercises strictly speaking, they ramp up the core/full body aspect with weights in hand.
I do multiple sets, am 59 years old and am stronger now than I have ever been (I have hit personal bests in just the last month) and have been exercising for decades. I vary my rep ranges between six and fifteen (but not limited to just those two extremes). My total exercise volume is between two and three hours a week.
Because I have been at this a long time I have learned to read my broad cycles. I push during the peak periods and back off during the valleys. I also adjust to good days and bad days within the broader cycle.
It is complex but natural movements with high neural skill components and complete muscle activation patterns that have moved me into peak condition while keeping me from injury.
I do not exercise to failure but stay in good form for all reps. I avoid full range of motion because it is a distortion of natural movement. Full range of motion with high loads in particular tends to damage joints.
Natural, functional strength is more complex than the simple study designs typically seen in the literature.
Hopefully these things that I have learned through many years of experimentation will be of interest to you, Ned, and your readers, and will foster some experimentation of your own.
Anonymous
The text below is all from an anonymous commenter’s notes on this post discussing the theory of supercompensation. Many thanks to this person for the detailed and thoughtful comment, which is a good follow-up on the note above about Scooby. In fact I thought that the comment might have been from Scooby; but I don’t think so. My additions are within “[ ]”. While the comment is there under the previous post for everyone to see, I thought that it deserved a separate post.
***
I love this subject [i.e., strength training]. No shortages of opinions backed by research with the one disconcerting detail that they don't agree.
First one opening general statement. If there was one right way we'd all know it by now and we'd all be doing it. People's bodies are different and what motivates them is different. (Motivation matters as a variable.)
My view on one set vs. three is based on understanding what you're measuring and what you're after in a training result.
Most studies look at one rep max strength gains as the metric but three sets [of repetitions] improves strength/endurance. People need strength/endurance more typically than they need maximal strength in their daily living. The question here becomes what is your goal?
The next thing I look at in training is neural adaptation. Not from the point of view of simple muscle strength gain but from the point of view of coordinated muscle function, again, something that is transferable to real life. When you exercise the brain is always learning what it is you are asking it to do. What you need to ask yourself is how well does this exercise correlate with a real life requirements.
[This topic needs a separate post, but one can reasonably argue that your brain works a lot harder during a one-hour strength training session than during a one-hour session in which you are solving a difficult mathematical problem.]
To this end single legged squats are vastly superior to double legged squats. They invoke balance and provoke the activation of not only the primary movers but the stabilization muscles as well. The brain is acquiring a functional skill in activating all these muscles in proper harmony and improving balance.
I also like walking lunges at the climbing wall in the gym (when not in use, of course) as the instability of the soft foam at the base of the wall gives an excellent boost to the basic skill by ramping up the important balance/stabilization component (vestibular/stabilization muscles). The stabilization muscles protect joints (inner unit vs. outer unit).
The balance and single leg components also increase core activation naturally. (See single legged squat and quadratus lumborum for instance.) [For more on the quadratus lumborum muscle, see here.]
Both [of] these exercises can be done with dumbbells for increased strength[;] and though leg exercises strictly speaking, they ramp up the core/full body aspect with weights in hand.
I do multiple sets, am 59 years old and am stronger now than I have ever been (I have hit personal bests in just the last month) and have been exercising for decades. I vary my rep ranges between six and fifteen (but not limited to just those two extremes). My total exercise volume is between two and three hours a week.
Because I have been at this a long time I have learned to read my broad cycles. I push during the peak periods and back off during the valleys. I also adjust to good days and bad days within the broader cycle.
It is complex but natural movements with high neural skill components and complete muscle activation patterns that have moved me into peak condition while keeping me from injury.
I do not exercise to failure but stay in good form for all reps. I avoid full range of motion because it is a distortion of natural movement. Full range of motion with high loads in particular tends to damage joints.
Natural, functional strength is more complex than the simple study designs typically seen in the literature.
Hopefully these things that I have learned through many years of experimentation will be of interest to you, Ned, and your readers, and will foster some experimentation of your own.
Anonymous
Friday, December 10, 2010
Living longer with an ideal BMI
Maintaining a healthy body mass index, or BMI, is one of the most important ways to help you live longer, according to a new study published in the December issue of New England Journal of Medicine.
BMI is not a perfect measure, but it is one of the simplest for estimating body weight. It is calculated by weight in pounds divided by height in inches squared and multiplying the number by 703, or by weight in kilograms divided by height in inches squared. What’s your BMI? Find out using this free calculator provided by the National Heart Lung and Blood Institute, of the National Institutes of Health.
The study’s findings support an optimal BMI in the “normal weight” range of 20 to 24.9, which is generally associated with the lowest risk of death from all causes including chronic diseases such as cardiovascular disease and cancer. The association was strongest among participants who were younger than 50 years old.
A BMI of 25 or more was associated with the highest mortality risks. The higher the BMI, the higher the likelihood of dying from cardiovascular disease.
“The results of our analysis are most relevant to whites living in affluent countries,” write the authors who pooled and analyzed data from 19 prospective studies encompassing 1.4 million white adults ages 19 to 80.
In the United States, among non-Hispanic whites, there was an estimated 11 percent of men and 17 percent of women with a BMI of 35 or higher in 2008.
The authors restricted the study to non-Hispanic whites based on self-reported ethnic group and controlled for pre-existing conditions, alcohol consumption, barbital status, education, and physical activity. They also excluded those with a BMI of less than 15 or higher than 50.
Smokers made up 25 percent of the study participants in the lowest BMI category of 15 to 18.4 and 8 percent of those in the highest BMI category.
Source: Berrington de Gonzalez A, Hartge P, Cerhan JR et al. Body-Mass Index and Mortality among 1.46 Million White Adults. NEJM 2010;363:2211-9.
Thoughts:
BMI is easy for anyone to measure, so this study gives us some back-up for using it as a way to speak to clients about real implications of obesity causing a shortened lifespan because of increased risk of cardiovascular disease and cancer.
It's important, however, to realize that while BMI may be easy it's possible for someone to be at a "normal weight" and still be "obese" -- dubbed normal weight obesity. This is still hazardous to your health, so you can't completely rely on BMI. Opt instead for body fat percentage measurement.
BMI is not a perfect measure, but it is one of the simplest for estimating body weight. It is calculated by weight in pounds divided by height in inches squared and multiplying the number by 703, or by weight in kilograms divided by height in inches squared. What’s your BMI? Find out using this free calculator provided by the National Heart Lung and Blood Institute, of the National Institutes of Health.
The study’s findings support an optimal BMI in the “normal weight” range of 20 to 24.9, which is generally associated with the lowest risk of death from all causes including chronic diseases such as cardiovascular disease and cancer. The association was strongest among participants who were younger than 50 years old.
A BMI of 25 or more was associated with the highest mortality risks. The higher the BMI, the higher the likelihood of dying from cardiovascular disease.
“The results of our analysis are most relevant to whites living in affluent countries,” write the authors who pooled and analyzed data from 19 prospective studies encompassing 1.4 million white adults ages 19 to 80.
In the United States, among non-Hispanic whites, there was an estimated 11 percent of men and 17 percent of women with a BMI of 35 or higher in 2008.
The authors restricted the study to non-Hispanic whites based on self-reported ethnic group and controlled for pre-existing conditions, alcohol consumption, barbital status, education, and physical activity. They also excluded those with a BMI of less than 15 or higher than 50.
Smokers made up 25 percent of the study participants in the lowest BMI category of 15 to 18.4 and 8 percent of those in the highest BMI category.
Source: Berrington de Gonzalez A, Hartge P, Cerhan JR et al. Body-Mass Index and Mortality among 1.46 Million White Adults. NEJM 2010;363:2211-9.
Thoughts:
BMI is easy for anyone to measure, so this study gives us some back-up for using it as a way to speak to clients about real implications of obesity causing a shortened lifespan because of increased risk of cardiovascular disease and cancer.
It's important, however, to realize that while BMI may be easy it's possible for someone to be at a "normal weight" and still be "obese" -- dubbed normal weight obesity. This is still hazardous to your health, so you can't completely rely on BMI. Opt instead for body fat percentage measurement.
Thursday, December 9, 2010
Gale Prince: "Food safety is a journey"
Gale Prince |
He began his talk by introducing us to the growing number of recalls in the United States. "Food safety has become a frequent topic for the media," he said. If you look at a 20-year trend, reccalls at retail have increased exponentially. Gail shared a graph of the trend and also details a few examples he's been involved with over the years.
The USDA has had a number of meat recalls, which Prince shows us picks up during the summer months of May through August. He says it is partly due to people cooking outside (such as at 4th of July) on the grill, who often leave their meat out or undercook their meat.
When you look at all the recalls of FDA, you also see the recalls going up, Prince said. He showed us a graph that showed that there were ove 8,000 just in the last year.
From 2004 to 2009 looking at class of recalls, most were class 1 due to salmonella problems. "Salmonella is a real challenge," Prince said.
There are three instances that accounted for 55 percent of food recalls in 2009.
- peanut paste
- powdered milk
- pistachios
Of all the recalls:
- 10 percent did not have a code - "this is like suicide for a company," Prince said.
- 51 percent involved multiple codes
Major Contributors
The major issues that generated recalls in 2009 were due to microbiological problems, allergens, mislabeling, foreign material (mainly plastic), chemical contamination, and inadequate processing.
Prince gave some advice in each of these areas. He tells the story of how Chinese honey is sometimes tainted with an antibiotic that is not allowed in the United States. The Chinese know that so they send to a different country to be relabeled as coming from that country.
Do recalls always happen late Friday afternoon? He has a theory that this is because manufacturers procrastinate to do it until the end of the week, which is a nightmare for the retailer. In addition, if you are a public company you need to inform the Securities and Exchange Commission (SEC) befoe you do the product recall, so companies often wait until thd market closes on Friday to do it.
New food vehicles identified in multistate outbreaks since 2006 are surprising like salmonella peanut butter despite lack of moisture, spinach and broccoli, carrot juice, hot peppers, pepper (salmonella can be in pepper for years), raw cookie dough, raw pistachios, and dog food.
What are the major contributing factors of recent recalls? Mostly, it's non-compliance with current Good Manufacturing Practices, failure to maintain food manufacturing facilities and equipment, non-compliant with a company's own Standard Operating Procedures (SOPs), and weaknesses in HACCP analysis.
Another factor is management responsibility for food safety for their products, for operations, for supply chain, etc. We're dealing with a global food ingredient procurement complexity these days, Prince said. It is much more difficult to manage.
He told the story of the infant formula recall that ended up leading to stores in cities of China not containing any infant formula, all due to melamine by some greedy businessmen who tainted their products.
When we see recalls of imported items, it is typically due to particular ingredients including milk powder. Food import problems include filth, production under unsanitary conditions, pesticide residues or use of approved pesticides, chemical contamination, or economic adulteration.
"There's a rough guess that 8 percent of food on the market is economically adulterated," he said.
Still, the biggest problem is simply salmonella. He showed us a slide of the variety of import alerts that are related to salmonella.
Recalls are also becoming more massive and expensive over time. The big peanut butter recall was a loss of over a year's worth of peanut butter. Ere is also a large legal impact coming from complaints. For example, the recall of 30,000,000 toys led to a hugely expensive settlement ($50 million).
"For those of you in the room in quality assurance, how would you like a new boss?" Prince asked. In these cases, when the government comes in, the government becomes your boss.
When you consider the economics of food safety, consider the loss of business, cost of loss of brand value, litigation, etc.
So, why the increase in all these cases?
- we concentrated our food production
- increased batch size
- product changes
- changes in food distribution
- consumer has changed
- science has changed (we're looking on ppb, versus ppt and ppm)
- epidemiology (the CDC plots info from food net surveillence trends in different parts of the country about salmonella, listeria, etc)
Salmonella is a serious problem. "When you look at what we've gone through as far as recalls, we're being bombarded from salmonella from everywhere around the world," Prince said.
The salmonella, campylobacter, and listeria outbreaks causes several fatalities when they occur.
The CDC uses the Pulse Net Database to track patterns, as in states, and has put together an outbreak team. In 2004, there was an outbreak in Tennessee that had outbreaks that the CDC tracked. They did a food history and through new technology was able to pin down peanut butter as the culprit of salmonella.
Then, peanut paste came along, which was more extensive because it was all over the country. "If it wasn't for Pulse Net they could've missed it," Prince said.
Traceability
What about traceability? Methods of traceability need to be improved. What Prince found is that most of the time traceability records were handwritten, which don't lend well to transferring electronically. Even a small accounting program or Excel spreadsheet would improve traceability.
Basically, traceability should include:
- Firm identification
- Product identification
- product coding, time code, etc.
Electronic traceability can have readable bar codes, tracking lot codes, shipping codes, etc.
"A good traceability program protects your business and provides a tool for managing supply chain," Prince said.
How do consumers see food safety? You can see that it's a big issue when you look at headlines of the melamine scandal, peanut butter recall, and so on. The data are clear: It's worth investing into food safety.
Consumers are largely concerned about germs, bacteria, pesticide residues (although not so much in this country), and terrorism. According to a Gallup poll, 29% felt recalls were serious concefn, 55 pecent would switch brands temporarily, 21% said would not purchase from company again. "Tell that to your sales department," Prince said. The changes in food purchasing is clear by sales shown in peanut butter and spinach well after a recall.
Don't forget social media, Prince warned. Monitor it well, because consumers are incredibly vocal, more than ever through these avenues.
Take Aways?
-Comply with GMPs
-Know your products
-Know your supply chain
-Know your process
-Audit your QC records (it's very educational)
-Maintain facility and equipment in sanitary manner
-Develop a food safety culture in your operation
FDA Food Safety Modernization Act
Prince then discussed the proposed FDA Food Safety Modernization Act, which is having troubles in the House currently. What will happen to it, is not known. Funding is an issue, along with other problems. These are the highlights:
-registration of facilities
-performance standards
-hazard analysis
-record access
-product traceability
-lab accreditation
-mandatory recall authority
-accreditation of 3rd party auditors (related to imports)
"If the bill is not passed before Christmas, the bill is dead and will need to be reintroduced in the new congress," he said.
Prince said that complacency is often a problem with food companies when it comes to food safety. "Are you taking things for granted," he said.
He gave these examples of companies, the first that went out of business, who offered up excuses.
- "We have been in business for 67 years and we have never had a problem."
- "We've always done it like that and it has never been a problem."
- "The inspector didn't say anything about that being a problem."
In summary, Prince said that companies must look to food safety as a majof focus of their business, to develop a culture of food safety, and to never become complacent.
"Food safety is a journey," he said.
Q&A
Amusingly, someone asked Prince what foods he avoids for sure. He said sprouts and raw oysters. He added, "The safest food is a hamburger."
Labels:
Food Science
M A N I F E S T O for Arts and Health update...
Dear friends...the first manifesto event was a great success and more sessions are planned for the new year. As a taster and keep you interested, the first group that met in October worked wonders and some of their thoughts and aspirations are here for you to see...but there, is more, much more to follow between now and June.
Networking Evening Events 2011
I’m pleased to announce that the North West Arts and Health Network evenings are continuing through 2011 and the dates below are confirmed, but are of course, subject to change and all updates will be made on the BLOG and Arts for Health main website http://www.artsforhealth.org
On the January 27th, Bits and Bats evening, I’m going to share some short archive films from the early days of the NHS in the late 1940’s. It’s all good fun and interesting given today’s climate of change. If you have any interesting archival footage that you’d like to share that relates to our Arts/Health agenda, please get in touch.
I’m still very keen for members of the network to influence these sessions and encourage you to send in ideas for themes for the evenings.
- January 27th
- March 24th
- May 26th
- July 28th
- September 29th
- November 24th
On the January 27th, Bits and Bats evening, I’m going to share some short archive films from the early days of the NHS in the late 1940’s. It’s all good fun and interesting given today’s climate of change. If you have any interesting archival footage that you’d like to share that relates to our Arts/Health agenda, please get in touch.
I’m still very keen for members of the network to influence these sessions and encourage you to send in ideas for themes for the evenings.
...a stimulus
I wonder what are the works of art that inspired you towards this arts/health agenda? Or, do certain works impact on your thinking. I gave a paper recently that explores the relationship between the pharmaceutical industry; the happiness industry and the arts. I had to edit such a lot out of it, and this includes a poem by Philip Larkin called, This Be The Verse, which links very much into my thoughts around the pathologising of depression and dissatisfaction with our lot. I'll leave you to work out any subtleties.
This Be The Verse
They fuck you up, your mum and dad.
They may not mean to, but they do.
They fill you with the thoughts they had
And add some extra, just for you.
But they were fucked up in their turn
By fools in old-style hats and coats,
Who half the time were soppy-stern
And half at one another’s throats.
Man hands on misery to man.
It deepens like a coastal shelf.
Get out as early as you can,
And don’t have any kids yourself.
Monday, December 6, 2010
Pressure-cooked meat: Top sirloin
Pressure cooking relies on physics to take advantage of the high temperatures of liquids and vapors in a sealed container. The sealed container is the pressure-cooking pan. Since the sealed container does not allow liquids or vapors to escape, the pressure inside the container increases as heat is applied to the pan. This also significantly increases the temperature of the liquids and vapors inside the container, which speeds up cooking.
Pressure cooking is essentially a version of high-heat steaming. The food inside the cooker tends to be very evenly cooked. Pressure cooking is also considered to be one of the most effective cooking methods for killing food-born pathogens. Since high pressure reduces cooking time, pressure cooking is usually employed in industrial food processing.
When cooking meat, the amount of pressure used tends to affect amino-acid digestibility; more pressure decreases digestibility. High pressures in the cooker cause high temperatures. The content of some vitamins in meat and plant foods is also affected; they go down as pressure goes up. Home pressure cookers are usually set at 15 pounds per square inch (psi). Significant losses in amino-acid digestibility occur only at pressures of 30 psi or higher.
My wife and I have been pressure-cooking for quite some time. Below is a simple recipe, for top sirloin.
- Prepare some dry seasoning powder by mixing sea salt, garlic power, chili powder, and a small amount of cayenne pepper.
- Season the top sirloin pieces at least 2 hours prior to placing them in the pressure cooking pan.
- Place the top sirloin pieces in the pressure cooking pan, and add water, almost to the point of covering them.
- Cook on very low fire, after the right amount of pressure is achieved, for 1 hour. The point at which the right amount of pressure is obtained is signaled by the valve at the top of the pan making a whistle-like noise.
As with slow cooking in an open pan, the water around the cuts should slowly turn into a fatty and delicious sauce, which you can pour on the meat when serving, to add flavor. The photos below show the seasoned top sirloin pieces, the (old) pressure-cooking pan we use, and some cooked pieces ready to be eaten together with some boiled yam.
A 100 g portion will have about 30 g of protein. (That is a bit less than 4 oz, cooked.) The amount of fat will depend on how trimmed the cuts are. Like most beef cuts, the fat will be primarily saturated and monounsatured, with approximately equal amounts of each. It will provide good amounts of the following vitamins and minerals: iron, magnesium, niacin, phosphorus, potassium, zinc, selenium, vitamin B6, and vitamin B12.
Pressure cooking is essentially a version of high-heat steaming. The food inside the cooker tends to be very evenly cooked. Pressure cooking is also considered to be one of the most effective cooking methods for killing food-born pathogens. Since high pressure reduces cooking time, pressure cooking is usually employed in industrial food processing.
When cooking meat, the amount of pressure used tends to affect amino-acid digestibility; more pressure decreases digestibility. High pressures in the cooker cause high temperatures. The content of some vitamins in meat and plant foods is also affected; they go down as pressure goes up. Home pressure cookers are usually set at 15 pounds per square inch (psi). Significant losses in amino-acid digestibility occur only at pressures of 30 psi or higher.
My wife and I have been pressure-cooking for quite some time. Below is a simple recipe, for top sirloin.
- Prepare some dry seasoning powder by mixing sea salt, garlic power, chili powder, and a small amount of cayenne pepper.
- Season the top sirloin pieces at least 2 hours prior to placing them in the pressure cooking pan.
- Place the top sirloin pieces in the pressure cooking pan, and add water, almost to the point of covering them.
- Cook on very low fire, after the right amount of pressure is achieved, for 1 hour. The point at which the right amount of pressure is obtained is signaled by the valve at the top of the pan making a whistle-like noise.
As with slow cooking in an open pan, the water around the cuts should slowly turn into a fatty and delicious sauce, which you can pour on the meat when serving, to add flavor. The photos below show the seasoned top sirloin pieces, the (old) pressure-cooking pan we use, and some cooked pieces ready to be eaten together with some boiled yam.
A 100 g portion will have about 30 g of protein. (That is a bit less than 4 oz, cooked.) The amount of fat will depend on how trimmed the cuts are. Like most beef cuts, the fat will be primarily saturated and monounsatured, with approximately equal amounts of each. It will provide good amounts of the following vitamins and minerals: iron, magnesium, niacin, phosphorus, potassium, zinc, selenium, vitamin B6, and vitamin B12.
Labels:
pressure-cooking,
recipe,
top sirloin
Saturday, December 4, 2010
Aubrey de Grey Response to Rose and Coles
Aubrey de Grey |
This is my take as how I understood the arguments. It was, admittedly, a bit hard to follow.
What we heard from Rose and Coles, explained de Grey, was that we have an exponential rise in deaths and then, we have what de Grey called, a "weird leveling off."
So, he said that as we get older, the data point to the fact that we eventually do reach a plateau in old age when mortality rates decline (passing the "aging phase" into a "biological immortality phase"), an argument of which Coles vehemently disagrees with.
He also said that it would probably not be a plateau like the type that Rose discussed in his talk, and as he showed in fruitflies.
Basically the data are sparse in these older populations, so there's no way we can really know what to expect.
"We definitely need more data," de Grey summarized.
And everyone else appeared to agree with that.
He also re-hashed his SENS approach for ridding the "accumulation of damage" that he says eventually causes the end of an individual's life.
De Grey pointed to the Gompertz Curve to support his arguments and the fact that because there are so few old people, there's too few data to make any kind of sense of whether there's an immortality phase or not.
Previously, about de Grey:
- Anti-Aging with Aubrey de Grey
- How to Prevent an Aging Crisis
Previously, about de Grey:
- Anti-Aging with Aubrey de Grey
- How to Prevent an Aging Crisis
Labels:
aging
Building Methuselahs
Michael Rose, evolutionary biologist |
He told us at H+ @ Caltech that aging is just a normal process of natural selection. It's obviously a "big picture" view versus a cellular or molecular view.
But to prove his point, he decided to trick natural selection and produce fruitflies that live five times longer than the average.
The trick? Take the fruitflies that can reproduce in old age, which still have most of their physiological function, and repeat.
Pretty simple. Eventually, you get longer-living fruitflies selected for late-life reproduction. And he shared data on how this all worked.
From the fruitfly data, Rose then explained, we can learn a bit about why humans age in the way they do, with pressures of reproduction playing in as a major factor. Also, we can make use of data on the flies and other animals that suggests that species enter a "biological immortality" phase once reaching an older age.
Then, he gave a two-part strategy into how humans can deter aging using "natural immortality technology." The strategy is easy and can be started tonight, he said.
What is natural for humans?
-It's not industrial lifestyle with cars, Twinkies, TV
-But is it the agricultural lifestyle or the hunter-gatherer lifestyle that is natural for us?
As an experimental evolutionist, Rose has research that shows that populations have adapted well to new environments in just 30 to 60 generations, so Eurasian populations are better adapted to the agricultural lifestyle.
How this happens? History in the environment, smaller effective population sizes, and lots of early accidental mortality leading to earlier plateaus.
So, people of ages under 30, should take an Andrew Weil approach to diet (as opposed to a Paleo diet and lifestyle) with plenty of fruits and vegetables, whole grains, and dairy.
However, he adds that as we age, the physiology of people with Eurasian ancestry progressively reverts back to the hunter-gatherer lifestyle."You will lose that adaptation to the novel environment as you age," Rose said.
So, the recipe for natural immortality?
- adopt a hunter-gatherer lifestyle after 40 if Eurasian, earlier if ancestry is less Eurasian
- use best modern medicine
- use autologous tissue repair when it becomes available (5+ years)
- use next-generation pharmaceuticals with less side effects
Interestingly, Aubrey de Grey expressed outrage that his recipe of immortality did not include rejuvenation research. He'll be speaking soon.UPDATE: I ended up writing a more in-depth take into Michael Rose's talk for KurzweilAI, which can be found here.
Labels:
aging
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