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(Comparative Anatomy and Physiology Brought Up to Date--continued, Part 7E)

Key Nutrients vis-a-vis Omnivorous
Adaptation and Vegetarianism (cont.)

Vitamin B-12: Rhetoric and Reality (CONT., 5 OF 5)

Feasible B-12 sources in evolution/pre-agricultural times

Both geophagy and, more rarely, coprophagy, are practiced on a limited scale by chimps; see Goodall [1986] for relevant discussion. It is known (from toothwear studies) that prehistoric humans display significant toothwear from "grit" or soil. No one knows how much grit prehistoric humans consumed, or how much might have been inadvertent (versus intentional), though the figure given above of 143 g/day of soil that would be required to achieve one's daily B-12 requirement is probably far more grit than anyone--even a less-than-fastidious prehistoric human--could tolerate. This suggests that geophagy was not a significant B-12 source for prehistoric humans.

Prior to agriculture, there were no domesticated crops or herds of domesticated animals. Consequently, there was no deliberate manuring of food crops--which is an agricultural practice, not a hunter-gatherer practice. Of course, some wild plants will--by chance or other reasons--receive limited amounts of wild animal manure. However, there is insufficient evidence to support a claim that such incidental, occasional manuring (of wild plants) would provide a reliable source of adequate B-12 (particularly in light of the extremely high bulk of unmanured plant foods required to meet B-12 requirements).

Potentially feasible plant B-12 sources--legumes and grains--not available to hunter-gatherers. Note that Mozafar found higher levels of B-12 in soybeans (a legume) and barley (a grain) than in spinach. Prior to the development of agriculture, such items (legumes, grains) would have been available only in very limited quantities to hunter-gatherer tribes.

Further, prior to the development of cooking technology (stone ovens and/or pottery), it would not be possible to cook (or sprout) significant quantities of such foods. (Think of the difficult task of roasting, or sprouting--without implements or containers--a pile of loose, small seeds.) Pottery is also required for cooking most vegetables other than tubers or hard squashes. That means early humans, if they were strictly vegan, would need to eat huge amounts of raw greens per day to satisfy B-12 requirements (and even larger amounts to meet minimal calorie requirements; see The Calorie Paradox of Raw Veganism for more details). The seasonal limits on the availability of greens (and other plant foods) in temperate climates, combined with the large amounts required, further disqualifies greens as a feasible B-12 source.

Fauna (animal foods) the consistent B-12 source in evolution. Accordingly, the only reliable/feasible sources of B-12, pre-agriculture, were coprophagy and the consumption of animal products. There is ample evidence of consumption of animal products in pre-agricultural times, but no evidence that coprophagy was ever a common practice. That leaves animal products (including insects) as the only reliable B-12 source in pre-agricultural times, and by implication suggests (if further evidence were needed beyond that already existing about prehistoric peoples) that there never existed any strictly vegan hunter-gatherers, as B-12 is an essential nutrient. (This also suggests that strict fruitarian/vegan diets were never a factor in human evolution.)

Vitamin B-12 and mercury

A not-very-clear claim occasionally made in fruitarian circles is that vitamin B-12 deficiency is caused not by a lack of vitamin B-12, but by the cobalt in B-12 undergoing oxidation due to heavy-metal action, specifically inorganic mercury from dental fillings (amalgam). However, a review of the limited information on the "theory" raises serious questions regarding its validity. Some of these reservations are:

In summary, the above points raise serious doubts about the (vague) mercury/B-12 hypothesis. Until such a theory is clarified, experimentally tested, and published in a credible scientific journal, it should be regarded as a speculative hypothesis.

Attempts to reverse burden of proof. Finally, this exercise also illustrates one of the bad habits of the raw/veg*n movement: adopt an unproven theory or claim, then aggressively demand that others disprove it. Such an approach is an attempt to reverse the burden of proof, and the purveyors of such untested hypotheses should not be so easily allowed to get away with such assaults against reason.

A note on Victor Herbert

Victor Herbert, whose research on B-12 has been cited here, is a controversial figure in alternative health circles, given that he lobbies against alternative medicine and supports government restrictions on alternative health. He promotes the allopathic "party line," i.e., drugs and surgery. Because of this, Victor Herbert the politician is very unpopular in alternative health/diet circles.

Unfortunately, many in such circles cannot distinguish between Victor Herbert the politician and Victor Herbert the research scientist. Herbert is one of the top researchers in the B-12 area and has a lengthy list of publications in scientific/professional journals. That record--extensive publication in refereed scientific journals--is a record that the anti-Victor Herbert lobby cannot match. Accordingly, I encourage you to evaluate his research on its technical merits, and not to be swayed by emotional or political sentiments.

Vitamin B-12: summary/conclusion


(Protein Digestion--Plant vs. Animal Sources / Taurine--a conditionally essential amino acid / Vitamin A and Beta-Carotene)

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GO TO PART 1 - Brief Overview: What is the Relevance of Comparative Anatomical and Physiological "Proofs"?

GO TO PART 2 - Looking at Ape Diets: Myths, Realities, and Rationalizations

GO TO PART 3 - The Fossil-Record Evidence about Human Diet

GO TO PART 4 - Intelligence, Evolution of the Human Brain, and Diet

GO TO PART 5 - Limitations on Comparative Dietary Proofs

GO TO PART 6 - What Comparative Anatomy Does and Doesn't Tell Us about Human Diet

GO TO PART 7 - Insights about Human Nutrition & Digestion from Comparative Physiology

GO TO PART 8 - Further Issues in the Debate over Omnivorous vs. Vegetarian Diets

GO TO PART 9 - Conclusions: The End, or The Beginning of a New Approach to Your Diet?

Back to Research-Based Appraisals of Alternative Diet Lore

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