Wednesday, December 21, 2011

Vitamin B12 and Human Nutritional Evolution

I once believed and argued that the fact that humans require vitamin B-12 provided substantial support for the idea that humans have a biological requirement for dietary meat.  My reasoning went thus:

Humans require vitamin B-12, and only animal products reliably provide natural bioactive vitamin B-12, therefore we must be adapted to and dependent upon meat-eating.

I have since realized that I made a few mistakes here.  Although we definitely require B-12, animal products are not the only reliable sources of natural bioactive B12, and human B-12 metabolism provides evidence that our ancestors adapted to an environment/diet that had a low availability of B-12 compared to currently recommended daily reference intakes.

Human B-12 Metabolism

Humans have enterohepatic circulation of vitamin B-12.[1 ] As noted by Herbert [2 ], this can allow an initially B-12 replete adult go 20-30 years without vitamin B-12 intake:



“The enterohepatic circulation of vitamin B-12 is very important in vitamin B-12 economy and homeostasis (27). Nonvegetarians normally eat 2-6 mcg of vitamin B-12/d and excrete from their liver into the intestine via their bile 5-10 mcg of vitamin B-12/d. If they have no gastric, pancreatic, or small bowel dysfunction interfering with reabsorption, their bodies reabsorb ~3-5 mcg of bile vitamin B-12/d. Because of this, an efficient enterohepatic circulation keeps the adult vegan, who eats very little vitamin B-12, from developing vitamin B-12 deficiency disease for 20-30 y (27) because even as body stores fall and daily bile vitamin B-12 output falls with body stores to as low as 1 mcg, the percentage of bile vitamin B-12 reabsorbed rises to close to 100%, so that the whole microgram is reabsorbed.”
What kind of environment/diet would naturally favor the survival of humans having such efficient recycling of vitamin B-12 but not of other B-complex vitamins? 

As a general principle, if an organism subsists on a diet with a low availability of a certain essential nutrient, it needs mechanisms for increasing absorption and retention of that nutrient, to prevent deficiency.  On the other hand, if an organism subsists on a diet with a very high availability of a certain essential nutrient, then it needs mechanisms for reducing absorption, detoxifying, and eliminating that nutrient.

Put in natural selection terms, only an ancient environment/diet with a low B-12 availability would have favored the survival and reproduction of humans who could recycle B-12 very efficiently.  An ancient environment/diet with a high B-12 availability would have made such a capacity unnecessary; on the contrary, an environment with a high availability of vitamin B-12 would have favored those who were less efficient at using B-12, or those who deliberately excreted excessive B-12 (in order to prevent B-12 accumulation and toxicity).

Thus, modern human B-12 metabolism suggests that modern humans are adapted to a diet that provides B-12 in less than required amounts on a daily basis, while occasionally providing larger doses in excess of requirements.  

Currently the National Academy of Sciences recommends that adults consume 2.4 mcg of B12 daily.  They calculated that this covers the needs of 98 percent of individuals, but most of us require less than this.  The following table shows the B12 contents of commonly consumed animal products:

Three ounces of beef or salmon provides the recommended intake, and three ounces of shellfish substantially exceeds the recommended 2.4 mcg.  In contrast, one would have to consume 24 ounces of chicken or turkey daily to ingest 2.4 mcg of B12. 
Non-animal B-12 Sources

As I said above, I previously accepted that only animal products reliably provide natural vitamin B-12.  Although this is a common belief, and probably a good general rule in modern industrialized nations, I think we have significant evidence that pre-industrial humans had other significant sources of vitamin B-12.

First, although animal products provide the most common vector for delivery of B-12 in modern industrialized nations, only microbes produce vitamin B-12. [3] Many microbes have the ability to produce B-12, among them the following genera: Aerobacter, Agrobacterium, Alcaligenes, Azotobacter, Bacillus, Clostridium, Corynebacterium, Flavobacterium, Micromonospora, Mycobacterium, Norcardia, Propionibacterium, Protaminobacter, Proteus, Pseudomonas, Rhizobium, Salmonella, Serratia, Streptomyces, Streptococcus and Xanthomonas. 

Bacillus megaterium is a common soil bacteria, not pathogenic to humans, and a producer of vitamin B-12.[4According to Patricia Vany of the Department of Biological Sciences at NIU, B. megaterium occurs in human breast milk.[15, third slide

Lactobacillus reuturi, a member of the gastrointestinal ecosystems of humans, poultry, swine, and other animals, and present in sourdough culture, produces vitamin B-12. [5]

Albert et al reported “the human small intestine also often harbours a considerable microflora and this is even more extensive in apparently healthy southern Indian subjects. We now show that at least two groups of organisms in the small bowel, Pseudomonas and Klebsiella sp., may synthesize significant amounts of the vitamin.”[6]

In 1995 Suzuki reported that the marine algae, nori, prevented all signs of B12 deficiency symptoms in 6 vegan children he studied:
“A nutritional analysis was conducted on the dietary intake of a group of 6 vegan children aged 7 to 14 who had been living on a vegan diet including brown rice for from 4 to 10
years, and on that of an age-matched control group. In addition, their serum vitamin B12 levels and other data (red blood cell count, hematocrit, hemoglobin, etc.) were determined in the laboratory. In vegans' diets, 2-4 g of nori (dried laver), which contained B12, were consumed daily. Not a single case of symptoms due to B12 deficiency was found. There were no statistically significant differences between the two groups with respect to any of the examination data, including B12 levels (p < 0.05). Therefore, consumption of nori may keep vegans from suffering B12 deficiency.” [7
[In 2005 Croft et al reported that algae acquire vitamin B12 through a symbiotic relationship with bacteria. (14) ]



In 2009 Koyyalamudi et al [8] reported that the common white button mushroom can provide vitamin B12 of value equivalent to that found in beef, beef liver, salmon, egg, and milk (not analogues).  Koyyalamudi et al determined that the mushrooms probably absorbed the B12 from bacteria inhabiting their growth medium:
“High concentrations of vitamin B12 were also detected in the flush mushrooms including cups and flats.  HPLC and mass spectrometry showed vitamin B12 retention time and mass spectra identical to those of the standard vitamin B12 and those of food products
including beef, beef liver, salmon, egg, and milk but not of the pseudovitamin B12, an inactive corrinoid in humans. The results suggest that the consumer may benefit from the consumption of mushroom to increase intake of this vitamin in the diet.” [8]
In 1994, Mozafar reported that spinach leaves and barley seeds grown on soil fertilized with organic matter or isolated B12 take up vitamin B12 into their tissues from the soil.  The spinach leaves and barley kernels were thoroughly washed with distilled water before being tested for B12 content, so this was not a case of finding B12 on soiled plants.  Their testing confirmed that these plants contained active B12, not inactive analogues.[9]

In summary, it appears that non-pathogenic soil microbes, human small intestinal bacteria, lactobacilli from fermented foods, some sea algae, common mushrooms, and plants grown on soil fertilized with animal manure can all can provide biologically active B12.   Any of these could have served as ongoing sources of B12 for prehistoric human ancestors, but modern circumstances may make these non-animal sources of B12 unreliable for modern humans.

I think it safe to assume that our prehistoric ancestors had more contact with soil than we do, sitting on it, sleeping on it, digging in it, and drawing water from sources in contact with the soil.  Humans like other primates are apt to touch their own lips from time to time, providing a vector by which soil microbes could enter the human gut.

Humans living in modern industrialized nations typically ingest multiple courses of oral antibiotics over a lifetime, reducing or eliminating the population of B12-producing bacteria residing in the small intestine.   All of our prehistoric ancestors would have been breast fed and probably kissed often, which transmits flora from one generation to another, and this transmission would not have been interrupted by antibiotic treatments.

Fermentation of plant foods, particularly fruits, occurs spontaneously in nature,  providing another route by which our ancestors may have ingested B12-producing lactobacilli.  Our ancestors almost certainly consumed any edible wild mushrooms and all of the plants they ate grew in soils teaming with bacteria and fertilized by fermented organic wastes, providing another B12 source.
All of this information suggests that modern hygiene, indoor lifestyles, antibiotics, and use of chemical rather than biomass fertilizers in farming have reduced the amount of B12 available to humans in modern urban environments from non-animal sources. 

Thus, the low availability of B12 from non-animal sources in modern urban environments is an artifact not reflective of preindustrial environments, and it appears probable that our prehistoric ancestors had more non-animal sources present in their environment, like the southern Indians studied by Albert et al.[6

My Fallacious Appeal to 'Nature'

When I previously argued that meat-eating is the 'natural' way to get B12, I committed the fallacy of appeal to nature. 


The problem here lies in these underlying assumptions:  1) all 'natural' behaviors are 'health-promoting' behaviors for modern urban humans,  and 2)  all 'unnatural' behaviors are unhealthful.

Consider these questions:
 
Is it natural for humans to wear clothing?  Does wearing clothing promote better health in some circumstances?  (Imagine people living in Minnesota rejecting clothing because their African ancestors didn't wear any.)
 
Is it natural for humans to live in igloos in the arctic circle?  Does living in igloos in the arctic circle promote the best of health?
 
Is it natural for humans to live in natural caves?  Do humans have the best possible health when living in natural caves?  Is a natural cave the best possible human shelter?
 
Is it natural for humans to commit homicide, engage in war, or eat human flesh?  Do any of these promote health? 
 
If all you mean by 'natural' is 'spontaneously occurring,' then all human behaviors are 'natural.' 

But is the 'natural' choice of our ancestors the best possible choice for modern humans of the present day?

Simply put, the fact that our ancestors did something then does not tell us that it is the best thing for us to do now.

The fact that our ancestors obtained B12 by a 'natural' route (eating meat) does not tell me that this is the optimal way for me to get B12 in our modern circumstances. 

The Nature of B12 Supplements

Artificial synthesis of B12 requires about 70 synthesis steps, making it impractical as a method for commercial production of B12.  “Therefore, today vitamin B12 is exclusively produced by biosynthetic fermentation processes, using selected and genetically optimized micro-organisms.” [10]

In other words, we cultivate, feed and breed living microbes so that they will produce the nutrient we want.  This practice seems similar to cultivating cattle to produce protein or B12.  If the former is ‘artificial,’ so is the latter.

Tablets of microbially synthesized B12, burgers of ground beef, capsules of vitamin D extracted from sheep’s hair, and tortillas made from corn are all end products of humans processing a raw material into a form that humans can conveniently consume.   If you reject B12 tablets as ‘unnatural,’ you should similarly reject ground beef burgers and vitamin D capsules.

The information above indicates that modern antibiotics and hygiene have reduced or eliminated intestinal flora that would otherwise produce B12 for us, and modern agricultural practices have reduced the B12 content of plant foods.  Similarly, modern indoor lifestyles have reduced our endogenous production of vitamin D.  We can reasonably use supplements to correct for these technology-induced deficiencies.

In short,  B12 supplements are the most reliable source of natural B12 in the modern environment.

Microbial B12 Supplements Recommended To People Past 50 Years Of Age

The Linus Pauling Institute at Oregon State University recommends that all people (including omnivores) over the age of 50 take a B12 supplement:

“Also, individuals over the age of 50 should obtain their vitamin B12 in supplements or fortified foods like fortified cereal because of the increased likelihood of food-bound vitamin B12 malabsorption.”[11]
In the publication Dietary Reference Intakes [12 ], the National Academy of Science Food and Nutrition Board concurs:



So these sources do not consider animal foods to be reliable sources of B12 for those of us more than 50 years of age.

Do we reject this advice because it is not 'natural' to take supplements?

Some B12 Options


Modern humans typically use their minds to identify their requirements for health and comfort, then develop and use appropriate technology to provide those requirements in the most efficient, safest possible way.  

Thanks to microbe-ranching, each modern urban human now has the opportunity to decide which of at least 3 courses s/he would prefer to take to ensure achievement of a healthy B12 status.

Course 1:  Obtain B12 directly from a cultivated microbial source, the production of which requires relatively little land and water and produces no urine or feces.  This source is free of saturated fats, cholesterol, heterocyclic amines, lipid peroxides, pathogenic organisms, or antigenic Neu 5Gc sialic acid (a suspect in human cancers and autoimmunity, found only in mammal’s products, 13 ).

Course 2: Obtain B12  from animal products, the production of which requires enormous amounts of land and water and produces tremendous amounts of urine and feces requiring safe disposal.  This source also supplies saturated fats and cholesterol,  heterocyclic amines (cooked meat), and lipid peroxides (cooked fat),  and is frequently contaminated with various potential pathogens (E. coli 0157:H7, MAR bacteria, salmonella, vibrio, etc.).  Red meats and mammalian milks also provide antigenic Neu5Gc sialic acid. [13]


As noted above, current science indicates that Course 2 is probably not reliable for people more than 50 years of age.

Course 3:  Use both B12 supplements and animal products.

Take your pick, or perhaps you will discover another way.

Thanks to the author/producer of the Primitive Nutrition video series for alerting me to the article on the B12 content mushrooms used in this post.

Monday, December 12, 2011

Primitive Nutrition Critique Parts 4 and 5

In The Protein Debate, Loren Cordain wrote the following:



He seems to be saying two things:

1)  Nutrition as a science suffers from “chaos, disagreement, and confusion.”

And

2) Use of ‘an evolutionary model’ would elimate “chaos, disagreement, and confusion”  by providing “coherent way to interpret the data.”

With regard to the first statement, I don’t know where he finds the “chaos, disagreement, and confusion” in nutrition science.  I can’t find this in any standard nutrition textbooks, in the National Academy of Sciences Food and Nutrition Board Dietary Reference Intakes publications, or among various expert panels making dietary recommendations to the public.  Among these scientific sources, I find very little or no debate as to human requirements for protein, fat, carbohydrate, vitamins, and minerals.   Also, the general guidelines for diet vary little from expert panel to expert panel.  Do I see a straw man here?

Or is Cordain preoccupied with the confusion among lay people, generated by the profusion of fad diet books?

Or is the disagreement he refers to the disagreement between his recommendation for a low-carbohydrate, high-protein diet, and the science which shows that humans only require a small amount of protein (one-third of what Cordain advocates) and lots of carbohydrates?

With regard to the second statement above, this implies that we should find even greater agreement among those who profess to use “an evolutionary model” to evaluate nutrition than we do among the conventional sources that Cordain derides. 

So let’s take a look.

Fruits and Vegetables

Regarding consumption of fruits and vegetables, expert panels of the USDAAmerican Heart Association, National Cancer Institute, American Institute for Cancer Research, World Cancer Research Fund, and many others generally agree that we benefit from eating fruits and vegetables.

In contrast, among those using an evolutionary model, Cordain believes that we should eat them because they provide important phytochemicals that protect against cancer and inflammation, but evolutionary model advocate and radiologist Kurt Harris, M.D. has once expressed the view that “plants and plant compounds are not essential or magic,” stating:
"Show me a randomized intervention that shows the benefits of fruits and vegetables. Such trials have been done and they have not shown a benefit." 
Unfortunately I do not know to which trials he refers as he provided no reference.  In that essay, Harris added that the idea that a particular plant compound is essential is inherently implausible and in need of a rigor of proof suitable for establishing the idea that there exists some extraterrestrial intelligence:
"To overcome the inherent implausibility of a particular compound or plant being essential or uniquely beneficial to health, there must be a high standard of proof.

"Similar to the level of proof there that there is extraterrestrial intelligence. It's implausible, so good evidence is needed."
Dr. Harris has amended his view on this topic somewhat since those words, and has written a blog indicating he believes that some plant compounds may provide benefits and "that eating some veggies is a hedge against going without unspecified beneficial compounds."

My question is, if the evolutionary model is so helpful for eliminating chaos and confusion, why didn't it clearly favor one or the other of these views about plants and plant compounds? 

Nutrition science recognizes many plant compounds essential to health (although apparently not those that Dr. Harris had in mind in his 'plant compounds are not essential' essay).  Those include, minimally, the vitamins thiamin, riboflavin, niacin, pyridoxine, pantothenic acid, folate, ascorbic acid, phylloqunione (vitamin K1), tocopherols (vitamin E); the essential fats linoleic and linolenic acids; and the essential amino acids isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, valine, and histidine.

All of these compounds are originally synthesized by plants and, except for niacin, appear in animal tissues only because the animal ate plants directly or ate another animal that ate plants.  The evidence that we require these plant compounds is thoroughly discussed in the various Dietery Reference Intakes publications of the Food and Nutrition Board of the National Academy of Sciences as well as numerous standard nutrition textbooks.

Amazingly, nutritional scientists discovered the essentiality of these nutrients for modern humans without speculating about the habits of stone age hunter-gatherers, consulting archaeologists, or asking anthropologists what isolated hunter-gatherers eat. Am I to believe that all of this talk of essential nutrients is nonsense because it was discovered without applying an evolutionary model?

In addition, while I would agree that it is implausible that any particular plant (e.g. spinach) is essential to health, plants world-wide have similar constituents (including non-vitamin phytonutrients).  For example, polyphenols occur in many species of plants world-wide.  To my knowledge, no nutrition scientist is arguing that any particular plant is essential or uniquely beneficial to human health, but many would suggest that humans have adapted to (possibly to become reliant upon) consumption of families of plant compounds (e.g. polyphenols).  I find this considerably more plausible than the idea of extraterrestrial intelligence (I don't know if Dr. Harris has changed his opinion here), since we already have established a human need for the plant compounds I have listed above.
So far as I can tell, except for vitamin D, which our own bodies synthesize if exposed to sunlight, not one nutrient mentioned in those FNB documents as an essential dietary component for humans is originally synthesized only by animals; i.e. all are originally synthesized by plants or microbes, or present as inorganic components of the earth's crust.  This table lists the essential nutrients and their original sources:

Nutrient
Original Source(s)
Essential amino acids (9)
Plants
Linoleic acid
Plants
Linolenic acid
Plants
Glucose
Plants
ß-carotene (provitamin A)
Plants
Tocopherols (vitamin E)
Plants
Cholecalciferol (vitamin D3)
Endogenous synthesis after sunlight exposure
Phylloquinone (vitamin K)
Plants
Thiamine (B1)
Plants and microbes
Riboflavin (B2)
Plants and microbes
Niacin (B3)
Plants
Pantothenic acid (B5)
Plants and microbes
Pyridoxine (B6)
Plants and microbes
Folate
Plants and microbes
Cobalamin (B12)
Microbes
Ascorbic acid (vitamin C)
Plants
Minerals
Rocks, soil (brought into the food chain by plants)

Cholesterol

Regarding dietary and blood cholesterol, scientific bodies consistently agree that dietary cholesterol is not beneficial or essential, and reducing cholesterol levels is desirable and necessary for avoiding cardiovascular disease (atherosclerosis).  For example, the NAS Food and Nutrition Board writes:

"There is much evidence to indicate a positive linear trend between cholesterol intake and low density lipoprotein cholesterol concentration, and therefore increased risk of coronary heart disease (CHD). A Tolerable Upper Intake Level is not set for cholesterol because any incremental increase in cholesterol intake increases CHD risk. Because cholesterol is unavoidable in ordinary diets, eliminating cholesterol in the diet would require significant changes in patterns of dietary intake. Such significant adjustments may introduce undesirable effects (e.g., inadequate intakes of protein and certain micronutrients) and unknown and unquantifiable health risks. Nonetheless, it is possible to have a diet low in cholesterol while consuming a nutritionally adequate diet. Dietary guidance for minimizing cholesterol intake is provided in Chapter 11."
Let me emphasize some lines from this passage:

"There is much evidence to indicate a positive linear trend between cholesterol intake and low density lipoprotein cholesterol concentration, and therefore increased risk of coronary heart disease (CHD)."

"....any incremental increase in cholesterol intake increases CHD risk."

Of interest, this paragraph illustrates my previous point that the dominant nutrition paradigm includes Cordain's belief that elimination of animal foods from the diet "may introduce undesirable effects (e.g., inadequate intakes of protein and certain micronutrients) and unknown and unquantifiable health risks."  This passage documents that Cordain's perspective is conservative, not revolutionary, compared to Campbell's, because, unlike Cordain and the Food and Nutrition Board, Campbell does not believe that eliminating cholesterol from the diet would result in protein or micronutrient deficiencies or 'unknown and unquantifiable health risks.'  

Nevertheless, the  Food and Nutrition Board maintains that dietary cholesterol (i.e. animal food) intake increases coronary heart disease risk.  The National Heart, Lung, and Blood Institute concurs and adds that "the higher your blood cholesterol level, the greater your risk for developing heart disease or having a heart attack."    Their publication "High Blood Cholesterol: What You Need To Know" includes this:

Again, no confusion or chaos apparent in the nutrition science Cordain has attacked.

In contrast, among those using the supposedly ‘unifying’ evolutionary model, Cordain believes that LDL cholesterol should be less than 70 mg/dL, but Kurt Harris, M.D. has expressed an opposing opinion of no confidence at all in any version of the lipid hypothesis:
"I do not believe in any of the versions of the lipid hypothesis, ranging from Ancel Keys' original idea that cholesterol or dietary fat clogs the arteries, to the currently fashionable one that “small, dense” LDL particles are like microscopic rodents that are designed to burrow under the intima of your blood vessels and kill you."
Why didn't their common use of an evolutionary model eliminate this disagreement?

Saturated Fat

Regarding saturated fat, scientific consensus documents such as the Food and Nutrition Board (FNB) of the NAS clearly state that we have no requirement for dietary saturated fat and any incremental increase in dietary saturated fat increases heart disease risk.  Here again I quote the FNB Dietary Reference Intakes for Fats:

"Saturated fatty acids are synthesized by the body to provide an adequate level needed for their physiological and structural functions; they have no known role in preventing chronic diseases. Therefore, neither an AI nor RDA is set for saturated fatty acids. There is a positive linear trend between total saturated fatty acid intake and total and low density lipoprotein (LDL) cholesterol concentration and increased risk of coronary heart disease (CHD). A UL is not set for saturated fatty acids because any incremental increase in saturated fatty acid intake increases CHD risk." [emphasis added]
You will find that all major expert panels around the world maintain this position. 

In contrast, among those claim to use the supposedly ‘unifying’ evolutionary model, Cordain believes the evolutionary model prescribes lean meat and low intake of dietary saturated fat, while Michael Eades, M.D. thinks that the evolutionary model prescribes fatty meat and high intake of saturated fat.

Should I really believe that the members of the Institute of Medicine's Food and Nutrition Board, composed of individuals who have invested their whole lives in studying nutrition both as scholars and bench scientists, do not understand the effect of nutrition on CHD risk, because they failed to use an evolutionary model?  Do you think the members of the FNB know the difference between correlation and causation?  Or did they get to the top of their field without mastering this concept presented in any undergraduate course in statistics or science?

Fitness 

Regarding fitness, at least one advocates of looking at things with an evolutionary model, Art DeVany believes that the scientific data proscribes distance running (note:  in the comments below Dr. Harris disavows using an exclusively evolutionary model to come to this conclusion), while Daniel E. Lieberman, a Harvard evolutionary biologist, and Dennis M. Bramble, a biologist at the University of Utah,  believe that an evolutionary model prescribes distance running.  If the evolutionary model is so powerful for eliminating chaos and confusion, why don't advocates of an evolutionary model agree on this point?

Confusion Within the Evolutionary Model

The ‘evolutionary model’ offered by Cordain and low-carbers also seems to introduce some confusion into the ‘evolutionary model’ itself.

According to this model, we should eat the imagined meaty low-carbohydrate diet of stone age mammoth hunters in order to increase our metabolic rates and lose body fat.    

Does this make evolutionary sense? 

I mean, would a high metabolic rate induced by a high protein/lean meat intake really benefit to a stone age hunter gatherer who already had difficulty getting hold of enough food to meet his metabolic needs?  

And would a low body fat level  achieved by a meaty low carb diet be an evolutionary advantage to humans dealing with extremely cold winters during the ice ages? 

Groking the Source of Confusion

Could it be that Paleo advocates are confused and confusing because they rely on an imaginary Grok for their guidance rather than science?   

By that I mean that the paleo diet ‘evolutionary’ model is based on largely imagining what stone age people did.  In case you didn’t notice, we don’t have any body composition data, diet or medical records, photos, or videos from the stone age people the paleo crowd wants to emulate.  

 This means you have to use your imagination to come up with any picture of them and their diets and lifestyles.   My imagination is different from yours, so we just might come up with different Groks to emulate. 

Cordain and his colleagues used their imaginations when they published "Estimated macronutrient and fatty acid intakes from an East African Paleolithic diet"  in the British Journal of Nutrition.  

I have realized that few if any of the conclusions in this document are subject to either confirmation or falsification.  You can invent any number of 'models' of paleolithic diets and none can be either confirmed or falsified simply because we have no direct access to or records of East African Paleolithic human diets.

Let me put it this way.  If I estimate that present-day Italian farmers consume 400 g of wheat bread and 3000 kcal per day in the winter, I can test my estimate by going to Italy, collecting diet records, and doing the math.  Others can test my estimate by the same procedure.  I could be proven wrong by someone else.  But if I estimate that Neanderthal females consumed 1200 kcal, 500 mg of DHA, and 30 mg of vitamin C daily in the summer, neither I nor anyone else can test my estimate against reality because neither Neanderthals nor their habitat exist any longer. 

And that is my introduction to these two videos:







Saturday, December 10, 2011

Primitive Nutrition Critique of Paleo Diet Conceptual Framework, Part 2

Paleo diet proponents promote their viewpoint as a scientific revolution akin to the Copernican revolution.
 
In his contribution to The Protein Debate , Loren Cordain claims that “The study of human nutrition remains an immature science because it lacks a universally acknowledged unifying paradigm." Apparently he thinks other sciences are "mature," i.e. virtually completed, which would be news to physicists, astrophysicists, chemists, and biologists, most of whom know that we have only scratched the surface of the world we study.

He goes on to claim that “nothing in nutrition seems to make sense because most nutritionists have little or no formal training in evolutionary theory, much less human evolution. Nutritionists face the same problem as anyone who is not using an evolutionary model to evaluate biology: fragmented information and no coherent way to interpret the data.”

I don’t know why he thinks nothing in nutrition seems to make sense.  Does he really think that if you open a textbook of nutrition, nothing in that book makes sense?  Are those chapters telling us about the scientifically established nutrient requirements of humans just gibberish to him?

Perhaps he thinks this because there seems to be a general scientific consensus that we can improve our health prospects by reducing animal food consumption, but he prefers to eat a lot of meat.  The American Heart Association, the American Institute for Cancer Research, and numerous other scientific medical organizations recommend eating more plant-based diets rich in fruits, vegetables, whole grains, legumes, nuts, and seeds, while reducing intake of animal products. Naturally, for someone who fervently believes in a low carbohydrate, high meat diet, the recommendations of the American Heart Association and the American Institute for Cancer Research don’t make sense.

 
Cordain sees his mission as providing a “universally acknowledged unifying paradigm”  through his paleo diet hypothesis.   According to him, we can ‘make sense’ of all the ‘confusing’ information he sees “By carefully examining the ancient environment under which our genome arose.”  Here's a snapshot of his claim in The Protein Debate
Certainly, nothing can be easier to do than examine the ancient environment under which our genome arose. We'll just get into our handy time machine that will take us back 200 million years to the emergence of the first mammals (a large part of the human genome emerged that long ago; we are a variation on a biological theme, not a totally unique entity) so we can “carefully examine” that environment first hand, rather than examine imaginary reconstructions offered by various creative minds.   

Similarly Rob Wolf refers to non-believers in the paleo diet paradigm as similar to members of the “flat-earth society,” implying that paleo believers are akin to Copernicus, while non-believers are akin to those who still believe that the earth is ‘flat.’

Paleo advocates also claim to be bucking ‘conventional wisdom,’ again implying that they have the advance take on diet and everyone else is in the dark ages believing in the nutritional equivalent of a ‘flat earth.’

So let’s see, which of these two statements is more aligned with ‘conventional wisdom’ and which is more ‘revolutionary’ in the context of historical and recent beliefs about human nutrition, biology, and medicine?

Loren Cordain’s Paleo Belief:  Humans must eat meat to obtain adequate protein and other nutrients, to build muscle mass and excel athletically, to maintain intelligence, and to maintain health.  People can reverse disease by eating more animal products and less plant foods.

T. Colin Campbell’s Vegan Belief: Humans do not need to eat any animal products to obtain adequate protein and other nutrients, to build muscle mass, to excel athletically, to maintain intelligence, or to maintain health.  We can reverse diseases by eating more plant foods and avoiding animal foods.

Given that approximately 98 percent of people in the U.S.A. eats meat on a daily basis, and many (including many paleo diet adherents) will immediately ask a vegan advocate “But where do you get your protein?”  I submit that the paleo diet belief is far from revolutionary, indeed I might consider it reactionary. 

Let me put it this way.  At this present time, very few people accept the idea that a vegan diet can adequately provide protein and general nutrition to the average human, which explains why very few people eat vegan diets.   Most people ‘believe’ that we need to eat meat, the way that, at the time of Copernicus, most people believed in a flat earth at the center of the sun’s orbit. 

This belief in the importance of meat to human nutrition has a long history.  I know of no time in Euro-American history when Campbell’s vegan belief was as widely accepted as the belief in a geocentric universe was at the time of Copernicus. On the contrary, the vegetarian perspective has been accepted by only a minority of people, mostly philosophers (e.g. Plato, Pythagorus) and medical doctors (e.g. Christoph Hufeland), throughout the history of Western civilization since the time of the Greeks.

In fact, T. Colin Campbell himself was initially indoctrinated to believe in meat and animal protein as critical to human health.  It was only through research that he came to reject this widely accepted belief.  That makes him more like Copernicus, challenging the widely held assumptions of his generation, whereas Cordain is simply agreeing with the long widely held belief that we have to eat meat to be healthy, smart, strong, and human.

Further, the idea that a vegan diet can reverse degenerative diseases contradicts the long-held belief of Western medical scientists that diet alone is inadequate for treatment of disease.  The orthodoxy believes in eating meat and using drugs and surgery to treat disease.  The revolutionary believes in avoiding meat and using a vegan diet as the primary tool in treatment of disease.

It seems to me that Cordain's paleo diet view aligns more with conventional wisdom and has more in common with the 'flat earth society,' and Campbell's vegan view bucks conventional wisdom and has more in common with Copernicus.

That’s my introduction to these two videos from PrimitiveNutrition which explore in greater depth the poor reasoning behind the paleo 'paradigm' starting with the fallacious appeal to nature (i.e. Eating meat is natural, therefore eating meat is optimal) which itself is based on a short-range view of 'natural' behaviors and their consequences (homicide is also natural, but if we all acted homicidal, we would be suicidal).

Friday, December 9, 2011

Primitive Nutrition Critique of Paleo Diet Part 1

 A much needed critical look at the fundamentals of paleo diet logic as offered by its leading proponents.  I truly wish I had had the acumen to have done this degree of critical thinking before I got involved in, let alone invested in, paleo dieting. 

Friday, December 2, 2011

Discovering Tao

Tracy and I have started a new blog together:  Discovering Tao: Training For Awakening Oneself.

My first posts there:

Staying Flexible features this video:



If You Want To Rebel, Act Kind about Pancho Ramos Stierle, the guy meditating surrounded by police in war-gear.

Meditation Disturbs The Peace?