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By Stephen Byrnes, PhD,
RNCP
This article is one part
of a series of articles that will run over several weeks.
The article is actually a revision of an older article that
we had previously posted on our site. You can find the original
article here.
Additionally, each article will be posted along with a rebuttal
by Dr. Michael Janson. You can find the rebuttal to this article
here.
Part 2 of 15 (Previous)
Myth #2: Vitamin B12
can be obtained from plant sources.
Of all the myths, this is perhaps the
most dangerous. While lacto and lacto-ovo vegetarians have
sources of vitamin B12 in their diets (from dairy products
and eggs), vegans (total vegetarians) do not.
Vegans who do not supplement their diet
with vitamin B12 will eventually get anemia (a potentially
fatal condition) as well as severe nervous and digestive system
damage; most, if not all, vegans have impaired B12 metabolism
and every study of vegan groups has demonstrated low vitamin
B12 concentrations in the majority of individuals (11).
Several studies have been done documenting
B12 deficiencies in vegan children, often with dire consequences
(12). Additionally, claims are made in vegan and vegetarian
literature that B12 is present in certain algae, tempeh (a
fermented soy product) and Brewer's yeast. All of them are
false as vitamin B12 is only found in animal foods. Brewer's
and nutritional yeasts do not contain B12 naturally; they
are always fortified from an outside source.
There is not real B12 in plant sources
but B12 analogues -- they are similar to true B12, but not
exactly the same and because of this they are not bioavailable
(13). It should be noted here that these B12 analogues can
impair absorption of true vitamin B12 in the body due to competitive
absorption, placing vegans and vegetarians who consume lots
of soy, algae, and yeast at a greater risk for a deficiency
(14).
Some vegetarian authorities claim that
B12 is produced by certain fermenting bacteria in the lower
intestines. This may be true, but it is in a form unusable
by the body. B12 requires intrinsic factor from the stomach
for proper absorption in the ileum. Since the bacterial product
does not have intrinsic factor bound to it, it cannot be absorbed
(15).
It is true that Hindu vegans living in
certain parts of India do not suffer from vitamin B12 deficiency.
This has led some to conclude that plant foods do provide
this vitamin. This conclusion, however, is erroneous as many
small insects, their feces, eggs, larvae and/or residue, are
left on the plant foods these people consume, due to non-use
of pesticides and inefficient cleaning methods.
This is how these people obtain their
vitamin B12. This contention is borne out by the fact that
when vegan Indian Hindus later migrated to England, they came
down with megaloblastic anaemia within a few years. In England,
the food supply is cleaner, and insect residues are completely
removed from plant foods (16).
The only reliable and absorbable sources
of vitamin B12 are animal products, especially organ meats
and eggs (17). Though present in lesser amounts than meat
and eggs, dairy products do contain B12. Vegans, therefore,
should consider adding dairy products into their diets. If
dairy cannot be tolerated, eggs, preferably from free-run
hens, are a virtual necessity.
That vitamin B12 can only be obtained
from animal foods is one of the strongest arguments against
veganism being a "natural" way of human eating.
Today, vegans can avoid anemia by taking supplemental vitamins
or fortified foods. If those same people had lived just a
few decades ago, when these products were unavailable, they
would have died.
To read
the rebuttal of the above article, please click here.
To read
the continuation of this article, please click here.
DR. BYRNES'
COMMENT:
At the outset, something needs to be
said regarding Dr. Janson’s frequent accusations that
I "provide no references." It is well-known that
my paper is being published in SEGMENTS and, accordingly,
not all of my references are revealed at one time, but they
will be as more of the paper is published. His implications
that my arguments have no foundation are therefore misleading,
unfair, and deceptive to the reader.
It needs to be re-emphasized to the
reader that Dr. Janson’s advocated diet is NOT a vegetarian
diet. Despite all of his double-talk to downplay the inclusion
of animal foods in human diets, the point is that he still
includes them.
He states that humans only "need
a small amount of [animal foods] to provide adequate vitamin
B12 to cover basic human needs." Given the difficulty
with which people absorb vitamin B12 and the many variable
factors that affect its absorption (hydrochloric acid, intrinsic
factor, thyroid hormone, and calcium), Dr. Janson’s advice
is misleading at best and dangerous at worst, given the known
consequences of vitamin B12 deficiency (1).
He then states that any supposed inadequacies
in B12 intake can be met, not by eating more animal foods,
but by taking vitamin pills. Is this his answer to the inadequacies
of vegetarian and vegan diets? How did our ancestors survive
before vitamin pills existed? By eating adequate animal foods,
that’s how. Instead of recommending the natural solution
to the B12 problem, he advises us to forsake healthful foods
and pop pills -- an unnatural solution, indeed.
Dr. Janson’s comments on vegetarian
diets and proneness to miscarriages deserve comment. In the
first place, Dr. Janson seems to think that miscarriages are
a "normal" occurrence for human females. Once again,
is it really normal? The fact that Dr. Janson has had miscarriages
in both omnivorous and vegetarian women is a sad testament
to the dilapidated health modern peoples suffer from. There
is nothing "normal" or "routine" about
this. It does, however, speak volumes about what women need
to do to remedy the situation: eat more animal foods.
Dr. Janson’s beliefs that vegetarian
diets are better for women who are either pregnant or want
to be pregnant are questionable. Studies have shown that vegetarian
women suffer from greater menstrual irregularity than evenly
matched omnivorous women. At the Milton S. Hershey Medical
Center, only 4.9% of premenopausal omnivorous women suffered
from menstrual irregularity, compared to a whopping 26.5%
in vegetarian women (2). The probability of menstrual regularity
was associated positively with protein and cholesterol intake
and negatively with dietary fiber and magnesium intake. Such
results are consistent with the hypothesis that premenopausal
vegetarian women have circulating estrogen concentrations
(3). Therefore, these women may also have decreased reproductive
capacity (2). Another study at the Hershey Medical Center
revealed that the frequency of menstrual irregularity was
significantly higher in a lacto-ovo vegetarian group of women
than in a matched group of nonvegetarian women (3).
Furthermore, since studies have shown
that vegetarians have higher homocysteine levels than non-vegetarians
(4) and since homocysteine is a known cause of birth defects
(5), it is certainly conceivable that vegetarian diets can
and do predispose women to greater risks of miscarriages.
Lastly, it is also known that vitamin B12 deficiency causes
reproductive failure (6). Since vegans, in general, have impaired
B12 metabolism and inadequate B12 intake (7), it is certainly
likely that vegan women are more at risk for miscarriages.
Dr. Janson’s statement that, "The
body manufactures vitamin A from carotene, which is abundant
in a diet high in fruits and vegetables," shows his lack
of knowledge on this subject. The carotene/vitamin A issue
is dealt with further along in my article under myth #4 so
I will not go into this too much here. Suffice it to say,
that carotene is not vitamin A and that the conversion of
carotenes into active vitamin A by the body is not an "automatic"
occurrence as Dr. Janson implies. The conversion can only
take place if several factors are present: bile, intestinal
lipase, thyroid hormone, dietary fat, and proper liver function
(8). Furthermore, diabetics and infants either cannot make
the conversion, or do so very poorly. Lastly, it takes approximately
six units of carotene to make just one unit of vitamin A --
hardly an optimal conversion (8). This, of course, emphasizes
the need to have adequate sources of vitamin A in our daily
diets and this nutrient is only found in animal foods and
fats.
His attempt to compare gorilla physiology
to human physiology is misleading: Humans are not gorillas.
Furthermore, all primates eat meat (9), even gorillas. Gorillas
will prefer more meat when in captivity, probably because
more of it is available than in the wild (10). So Dr. Janson’s
attempt to persuade readers to adopt a more gorilla-like diet
is off-base.
Dr. Janson’s warnings about mercury
poisoning from fish are curious given that he himself eats
fish and recommends the same to readers. He then, again, recommends
supplements of fish oil over real food to get one’s EPA
and DHA. I like to think that the health-conscious consumer
will make the effort to obtain clean food sources of plants
and animals and not have to rely on supplements to meet their
nutritional needs.
His contentions that a vegetarian diet
is the healthiest and is "a reflection of the vast weight
of the available scientific data," is flatly contradicted
by a close analysis of the data. Though it is true that a
number of studies suggest a causal relationship between meat
and certain chronic diseases like cancer and heart disease,
conclusions drawn from these studies remain controversial
and many other studies have taken issue with them (11). These
studies are discussed further along in my article in sections
six and seven.
Furthermore, a study of vegetarian
California Seventh Day Adventists revealed that, while they
did have lower rates than the general population for some
cancers (e.g., breast and lung), they had higher rates for
several others (e.g., prostate, Hodgkin’s disease, malignant
melanoma), some quite significantly. The rates for endometrial
cancer were so high in Adventist women that the researchers
expressed alarm (12). As meat consumption increased in Spain
(and carbohydrate consumption decreased), heart disease rates
dropped (13).
Further, Dr. Janson seems to implication
that articles that show meat not to be harmful are few and
far between is simply wrong. For example, in a comprehensive
review of the available literature, Australian researchers
concluded that there was no evidence that meat caused cancer.
This review paper has over 200 references (14).
In the same vein, his statement that
animal fat increases cancer risk is also wrong as several
studies have shown (15). Furthermore, beef and milk fat contain
a fatty acid known as conjugated linoleic acid, a known anti-carcinogen
(16).
Dr. Janson’s claims of ill health
from meat-eating also do not stand the test of history. If
it is indeed true that meat-eating and saturated fat cause
heart disease, cancer, diabetes, etc., where is the evidence
for this in native peoples the world over who eat high meat
diets? Investigations of the Masai and Eskimo, who are almost
100% carnivorous (before modernization), for example, revealed
no chronic diseases (17). In a controlled experiment carried
out at Bellevue Hospital, Viljemar Stefansson and Karsten
Andersen ate nothing but raw meat and substantial quantities
of animal fat for a period of one year. No adverse effects
were noted and Andersen’s health actually improved (18).
If the meat=disease theory were true, then logically one would
find disease in heavy meat-eating populations, but such is
not the case. Therefore, Dr. Janson’s claims are false.
Dr. Janson’s comments on the conflicting
studies on vegetarian health claims are misleading. First,
he gives the impression that there are very few studies which
show risk for vegetarian diets and fewer still that show protective
effects of more animal foods in the diet (disproven by my
paper and the additional references cited above). Second,
even if his dubious claims were true, scientific truth is
not determined by a "majority vote" and it only
takes one exception to disprove a theory.
His comments on vegans and immune function
are misleading as the studies are conflicting. One study showed
that vegans had lower platelet and leukocyte levels than matched
omnivores (19).
Perhaps the weakest part of his rebuttal
is his section on Paleolithic diets. Despite his claims to
the contrary, the scientific evidence shows that our ancestors
ate lots of meat and fat. For 99 percent of the time of human
evolution, humans hunted animals and gathered wild plant foods
(20). Australopithecines, the first humans, relied heavily
on animal foods, both hunted and scavenged (21). Plant foods
were not a viable dietary option for early humans because
most plant foods are poisonous in their raw states and early
humans did not know how to cook or control fire to cook (22).
Therefore, early humans could not have survived on the limited
plant foods available because they could not have provided
enough calories or nutrients to survive.
Furthermore, cross-cultural surveys
have shown that people prefer animal foods over plant foods
(23). This is because hunting animals and eating them provides
more food with less effort. It takes almost an entire day
of foraging to gather the amount of food contained in one
small animal (24). Furthermore, hunting provided the means
for early humans to develop mental skills needed to hunt,
as well as social skills to cooperate in the hunt (25). In
other words, hunting animals and eating them advanced human
evolution.
Dr. Janson’s claim that Paleolithic
peoples could get away with eating more meat with no ill effects
because they led extraordinarily vigorous lives is not likely
to be true. Hunting and gathering is the primitive equivalent
to a life of luxury (26). It was the agriculturalists who
had to toil and suffer for food (27).
Dr. Janson’s statement that, "Just
because cave-humans ate meat is not an argument to continue
doing so," flies in the face of evolution and genetics.
Human dietary requirements are genetically programmed (28).
Since we evolved as meat-eaters, we should continue being
meat-eaters today. Research shows quite clearly that as humans
abandoned animal foods and fats in favor of more "vegetables,
fruits, whole grains, and beans," our health deteriorated.
Skeletal remains of European populations reveal a slow, steady
increase in tooth decay from the Neolithic period when agriculture
first began until today, where it has skyrocketed (29). These
findings simply confirm Dr. Price’s research: as people
eat more carbohydrates, even complex ones, dental decay escalates.
Dr. Joseph Brasco’s words further
enumerate the health consequences of a diet based on grains,
rather than animal foods:
Generally, in most parts of the world,
whenever cereal-based diets were first adopted
as a staple food replacing the primarily animal-based diets
of hunter-gatherers, there
was a characteristic reduction in stature, a reduction in
life span, an increase
in infant mortality, an increased incidence of infectious
disease, an increase in
diseases of nutritional deficiencies (i.e., iron deficiency,
pellagra), and an increase
in the number of dental caries and enamel defects. (29a)
Furthermore, research shows that low-fat/high
carbohydrate diets (the type that Dr. Janson is advocating)
place us at greater risk for heart disease (30), cancer (31),
and diabetes (32). Should we follow such a deadly diet?
Dr. Janson apparently lacks a knowledge
about the nutrients in meat. Meat provides adequate levels
of cysteine which the body then uses to create glutathione,
a potent antioxidant that the liver primarily uses to detoxify
harmful substances, like the trace amounts of chemicals and
pesticides in commercial meats. His statement that plant-based
diets are better because of their better antioxidant profiles
is not altogether true as several studies have shown that
vegetarians have lower total antioxidant status than omnivores
(33). Furthermore, cysteine is most abundantly found in meat
and other animal foods -- not plants.
Lastly, his comments about hormones
in meat are misleading. Yes, do everything you can to avoid
them (I said this in my response), but hormones in the form
of pesticides are still present in commercially-grown plant
foods as pesticides are synthetic estrogen compounds. Once
again, Dr. Janson places an undue emphasis on the toxicity
of commercial meat while ignoring the very same hazards in
commercial produce.
NOTES
1. L. Dunne. The Nutrition
Almanac, 3rd ed. McGraw Hill Publishing, NY; 1990, 31-32;
J Groff and S Gropper. Advanced Nutrition and Human Metabolism.
Wadsworth/Thomson Learning, CA; 2000, 299-300.
2. A. Pedersen and others.
Menstrual difficulties due to vegetarian and non-vegetarian
diets. Am J Clin Nutr, 1991, 53:879-85.
3. T Llooyd and others.
Urinary hormonal concentrations and spinal bone densities
of premenopausal vegetarian and non-vegetarian women. Am J
Clin Nutr, 1991, 54:1005-10.
4. (a) Herrmann, Schorr,
Purschwitz, Rassoul, Richter. Total homocysteine, vitamin
B (12), and total antioxidant status in vegetarians. Clin
Chem, 2001, 47(6):1094-10; (b) D Mazzano and others. Cardiovascular
risk factors in vegetarians. Normalization of hyperhomocysteinemia
with vitamin B(12) and reduction of platelet aggregation with
n-3 fatty acids. Thromb Res 2000 Nov 100:153-60.
5. Rosenquist TH, Ratashak
SA, Selhub J. Homocysteine induces congenital defects of the
heart and neural tube: effect of folic acid. Proc Natl Acad
Sci U S A 1996 Dec 24;93(26):15227-32; (b) Langman LJ, Cole
DE. Homocysteine. Crit Rev Clin Lab Sci 1999 Aug;36(4):365-406
.
6. J Reprod Med, 2001, 46:209-212.
Summary posted at /sites/articles/archive/2001/05/12/vitamin-b12-part-two.aspx
7. AL Rauma and others.
Vitamin B-12 status of long-term adherents of a strict uncooked
vegan diet ("living food diet") is compromised.
J Nutr, 1995, 125:2511-5; (b) MG Crane and others. Vitamin
B12 studies in total vegetarians (vegans). J Nutr Med, 1994,
4:419-30; c) I Chanarin and others. Megaloblastic anaemia
in a vegetarian Hindu community. Lancet, 1985, Nov 2:1168-72
; (d) M Donaldson. Vitamin B12 and the Hallelujah Diet, posted
here;
(e) MS Donaldson. Metabolic vitamin B12 status on a mostly
raw vegan diet with follow-up using tablets, nutritional yeast,
or probiotic supplements. Ann Nutr Metab, 2000, 44(5-6):229-234
.
8. (a) Dunne, op cit., 14;
(b) I Jennings. Vitamins in Endocrine Metabolism. (Charles
Thomas; London), 1970, 39-57.
9. J. Goodall. In the Shadow of Man. Boston; 1971; (b) HL
Abrams. Vegetarianism: An anthropological/nutritional evaluation.
J Appl Nutr, 1980, 32:53-87.
10. Abrams, op cit.
11. GV Mann and others.
Cardiovascular diseases in African Pygmies. J Chronic Dis,
1961, 15:341; (b) GV Mann. Diet-heart: End of an era. NEJM,
1977, 297:644-650; c) JE Enstrom. Colorectal cancer and consumption
of beef and fat. Brit J Canc, 1975, 32:432-9; (d) MG Enig
and others. Dietary fat and cancer trends -- a critique. Fed
Proc, 1978, 37:2215-20; (e) JL Lyon and others. Cancer incidence
in Mormons and non-Mormons in Utah 1966-1970. NEJM, 1976,
294:129-33; (f) C Glueck and W Connor. Diet-coronary heart
disease relationships reconnoitered. Am J Clin Nutr, 1978,
31:737-57.
12. J Mills and others.
Cancer-incidence among California Seventh-day Adventists,
1976-1982. Am J Clin Nutr, 1994, 59 (suppl):1136S-42S; see
also RL Phillips. Canc Res, 1975, 35:3513-3522 which showed
that Seventh Day Adventist physicians had higher colon cancer
rates than the general population.
13. L Serra-Majem and others.
How could changes in diet explain changes in coronary heart
disease? The Spanish Paradox. Amer J Clin Nutr, 1995, 61:1351S-9S.
14. JS Baghurst and others.
Does red meat cause cancer? Aust J Nutr Diet, 1997, 54(4):S1-S44.
15. MG Enig and others.
Dietary fat and cancer trends -- a critique. Fed Proc, 1978,
37:2215-20; (b) M Holmes and others. Association of dietary
intake of fat and fatty acids with risk for breast cancer.
JAMA, 1999, 281:914-920; c) A Wolk and others. A prospective
study of the association of monounsaturated fat and other
types of fat with risk of breast cancer. Arch of Inter Med,1998,
158:41.
16. C. Ip and others. Conjugated
Linoleic Aicd-Enriched Butter Fat Alters Mammary Gland Morphogenesis
and Reduces Cancer Risk in Rats. Jnl of Nutr, 129:2135-2142;
Hubbard NE, Lim D, Summers L, Erickson KL. Reduction of murine
mammary tumor metastasis by conjugated linoleic acid. Cancer
Lett 2000 Mar 13;150(1):93-100.
17. HH Draper. The Aboriginal Eskimo diet in modern perspective.
Amer Anthropol, 1977, 79:309-316; (b) GV Mann. Atherosclerosis
and the Masai. Amer J Epidem, 1972, 95:6-37; (c) GV Mann.
Diet and disease among the milk and meat eating Masai warriors
of Tanganyika. Food Nutr, 1963, 24:104.
18. CW Lieb. The effects
on human beings of a twelve months exclusive meat diet. JAMA,
1929, July 6, 20-22.
19. EH Haddad and others.
Dietary intake and biochemical, hematologic, and immune status
of vegans compared with nonvegetarians. Am J Clin Nutr 1999
Sep 70:586S-593S.
20. MD Leakey. Olduvai Gorge,
vol. 3. Cambridge University Press; NY, 1971; (b) RB Lee and
I DeVore. "Problems in the studies of hunters and gatherers,"
in Lee and DeVore, eds., Man the Hunter. Aldine Publishing,
Chicago, 1968, 3-20.
21. HL Abrams. The relevance
of paleolithic diet in determining contemporary nutritional
needs. J Appl Nutr, 1979, 31:43-59; (b) MN Cohen. The Food
Crisis in History. Yale University Press, CT., 1977, 15; c)
Leakey, op cit. (d) AC Leopold and R Ardrey. Toxic substances
in plants and the food habits of early man. Science, 1972,
176:512-4; (e) GB Schaller and G Lowther. The relevance of
carnivore behavior to the study of early hominids. Southwest
J Anthrop, 1969, 25:307-41.
22. HL Abrams. Fire and
cooking as a major influence on human cultural advancement:
An anthropological/botanical nutritional perspective. J Appl
Nutr, 1986, 1,2:24-31.
23. HL Abrams. The Preference
for Animal Protein and Fat: A Cross-Cultural Survey. Food
and Evolution: Toward a Theory of Human Food Habits. M Harris
and EB Ross, eds. (Temple University Press; PA), 1987, 207-223.
24. HL Abrams. The relevance
of Paleolithic diet . J Appl Nutr, 1979, 31:43-59; Edmund
White and Dale Brown. The First Men. Little, Brown, and Co.,
MA., 1973, 68-94.
25. J Bronowski. The Ascent
of Man. Little, Brown, and Co, MA., 1972, 42-56.
26. M. Harris. Cannibals
and Kings. Vintage Books, NY, 1991, 11-25.
27. Ibid, 29-47.
28. L Cavalli-Sforza. "Human
evolution and nutrition," in DN Walcher and N Kretchmer,
eds., Food, Nutrition, and Evolution: Food as an Environmental
Factor in the Genesis of Human Variability. Masson, NY, 1981,
1-7; (b) J Yudkin. "Archaeology and the nutritionist,"
in PJ Ucko and GW Dimbley, eds., The Domestication and Exploitation
of Plants and Animals. Aldine, Chicago, 1969, 547-52.
29. C Wells. Bones, Bodies,
and Disease: Evidence of Disease and Abnormality in Early
Man, New York, 1964; (b) GH Pelto and PJ Pelto. The Cultural
Dimensions of the Human Adventure. New York, 1979, 292-301.
29a. J Brasco. Low Grain
and Carbohydrate Diets Treat Hypoglycemia, Heart Disease,
Diabetes Cancer and Nearly ALL Chronic Illness. Posted here
and accessed on January 4, 2002. See also L. Cordain. Cereal
grains:humanity’s double-edged sword. World Rev Nutr
Diet, 1999, 84:20-73.
30. DM Dreon and others.
A very-low-fat diet is not associated with improved lipoprotein
profiles in men with a predominance of large, low-density
lipoproteins. Amer J Clin Nutr, 1999, 69:411-8; (b) F. Jeppesen
and others. Effects of low-fat, high-carbohydrate diets on
risk factors for ischemic heart disease in post-menopausal
women. Am Jnl Clin Nutr, 1997; 65:1027-1033; (c) I. Zavaroni
and others. Risk factors for coronary artery disease in healthy
persons with hyperinsulinemia and normal glucose tolerance.
New Eng J Med, 1989, Mar 16, 320:11:702-6
31. S. Francheschi and others.
Intake of macronutrients and risk of breast cancer. Lancet,
1996, 347:1351-6; (b) W.J. Lutz. The colonisation of Europe
and our Western diseases. Med Hypotheses, 1995, 45:115-120;
(c) J. Witte and others. Diet and premenopausal bilateral
breast cancer: a case control study. Breast Canc Res &
Treat, 1997, 42:243-251; (d) S. Francheschi and others. Food
groups and risk of colo-rectal cancer in Italy. Inter J Canc,
1997, 72:56-61; (e) C. Allan and W. Lutz. Life Without Bread.
Keats Publishing; CT., 2000, 163-177.
32. G Reaven and others.
Persistence of hypertriglyceredemic effect of low-fat, high-carbohydrate
diets in NIDDM patients. Diabetes Care, 1989, 12:94-101; (b)
G Reaven and others. Effects of sucrose on carbohydrate and
lipid metabolism in NIDDM patients. Diabetes Care, 1989, 12:62-66.
33. (a) Herrmann, Schorr,
Purschwitz, Rassoul, Richter. Total homocysteine, vitamin
B (12), and total antioxidant status in vegetarians. Clin
Chem, 2001, 47(6):1094-10; (b) D Mazzano and others. Cardiovascular
risk factors in vegetarians. Normalization of hyperhomocysteinemia
with vitamin B(12) and reduction of platelet aggregation with
n-3 fatty acids. Thromb Res 2000 Nov 100:153-60.
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