Description of natural hygiene diet, and diets of those in survey. For readers unfamiliar with the term "natural hygiene," in this context the classical definition refers to a predominantly raw diet of fruits, vegetables, nuts, and seeds. Note that the data were collected in 1979, at which point the ANHS had a long history of strongly emphasizing raw plant foods. Since then, the ANHS has revised their position. While still emphasizing plant foods (veganism), the stress previously placed on raw foods has been deemphasized; and adding cooked starches (grains, legumes, tubers, squashes) to the diet is now recommended.

Based on the dietary data provided in the survey form, subjects were classified according to their diet, with vegans being defined as those who consumed no animal foods, lacto-vegetarians as those who consumed dairy as their only animal food, lacto-ovo-vegetarians as those who consumed dairy and eggs, and semi-vegetarians as those who consumed animal flesh foods two or less times per month. It should be noted here that because the subjects were recruited at an ANHS convention, and the ANHS emphasized raw foods at the time, at least some of the subjects in the vegan category presumably were raw or predominantly raw vegans.

Serum B-12 levels of vegan natural hygienists below lower limit of normal range. Dong and Scott [1982, pp. 214-215] report:

Among subjects who did not supplement their diets with B-12 or multiple vitamin tablets, 92% of the vegans, 64% of the lacto-vegetarians, 47% of the lacto-ovo-vegetarians and 29% of the semi-vegetarians had serum B-12 levels less than 200 pg/ml [the lower limit of the normal range]. Mean serum B-12 levels of the dietary groups increased with increasing dietary sources of B-12...

Some cases of mild macrocytosis [pernicious anemia] were seen among the vegetarians, but fewer than expected...

The data indicates that increasing diversity of animal products consumed increased the serum B-12 level.

Mean Serum B-12 Levels (pg/ml)
Observed at 1979 ANHS Annual Convention

from Dong and Scott [1982]

• B-12 in living foods (raw vegan) diets. Rauma et al. [1995] provides data on the vitamin B-12 status of living-fooders, i.e., individuals who follow the raw vegan "living foods" diet as taught by Ann Wigmore. Such a diet emphasizes raw sprouts, fermented foods, blended/liquefied foods (raw soups), dehydrated foods, and wheatgrass juice. There were two components to their study: a cross-sectional component and a longitudinal study.

  Technical note concerning measurement units in Rauma et al. [1995] study. The study under discussion here reported results in pmol/L, rather than pg/ml as used by the other studies cited in this section. However, there are reasons to believe that the units for the cross-reference portion of the subject study are actually pg/ml, rather than pmol/L. Because of this, the numbers below (which come from the cross-reference part of the study) are listed here as pg/ml. The rationale for this is as follows:

  First, as the concern here is a potential inadvertent mix-up between the two different measurement units, pmol/L (pico-moles per liter) and pg/ml (picograms per milliliter), note that the relationship between the two units of measure is:

  1 pmol/L B-12 = ~1.35 pg/ml

  where the ~ above indicates approximately. This follows from the definition of moles, and simple algebra with the units, using the molecular weight of B-12.

  • If the unit "mole" is unfamiliar to you, check an elementary chemistry text, e.g., Oxtoby and Nachtrieb [1986, pp. 21-23] for explanation.

  • Note that the term vitamin B-12 does not refer just to one specific molecule; instead the term is applied to a number of biologically active compounds (though not the biologically inactive B-12 "analogues"), an approximate average molecular weight for which is 1350 [Schneider and Stroinski 1987, pp. 56-59]. These slight variations in molecular weight between different active B-12 compounds account for the approximate nature of the conversion ratio between the two measures pmol/L and pg/ml.

  Second, Rauma et al. [1995] report that one test kit had a lower reference limit of 150 pmol/L, which after conversion is approximately 200 pg/ml, the standard. However, the kit that was used for the cross-reference study (and the numbers below) supposedly had a lower reference limit of 200 pmol/L, which after conversion is 270 pg/ml--a number that is non-standard and appears to make no sense. Further adding to the uncertainty here is that Rauma et al. cite the names of two different manufacturers for the second B-12 assay kit, but email correspondence with the technical support departments of both the named companies reveals that neither company ever made B-12 assay kits.

  Although the units issue is confusing, the weight of the evidence seems to point to the units for the cross-reference study portion as being pg/ml, and that is how they are reported here. As this website article is being published, an inquiry is pending with the authors of the cited study. When the issue is resolved, this section will be updated as appropriate. Until then, please recognize that there is some uncertainty regarding the measurement units for this study [Rauma et al. 1995].

  The cross-sectional analysis compared the serum B-12 levels of 21 living-fooders, each paired with a control (standard Western diet, i.e., non-vegetarian) matched by sex, age, and other factors. The findings of the cross-sectional study found that the control group (standard Western diet) had significantly higher serum B-12 levels (311 pg/ml) than the living-food vegans (193 pg/ml). Note that the average B-12 level reported for living-fooders, 193 pg/ml, is close to the lower limit of the normal range: 200 pg/ml. However, Rauma et al. [1995] report that 57% of the living-foods vegans had B-12 levels below 200 pg/ml.

  The longitudinal study was conducted over a 2-year period, using 9 individuals who reportedly followed the living-foods vegan diet long-term. They note [Rauma et al. 1995, pp. 2513, 2514]:

  The longitudinal study revealed a decrease in serum vitamin B-12 concentrations with time in six of nine subjects, indicating that the supply of vitamin B-12 from the "living food diet" is inadequate to maintain the serum vitamin B-12 concentration...

  [T]he occurrence of low serum vitamin B-12 concentrations in over 50% of the long-term adherents of this diet warrants further study of the possible health risks involved.

• B-12 levels in long-term vegans. Bar-Sella et al. [1990] examined the serum B-12 levels of 36 strict vegans who had followed the diet long-term (5-35 years). The vegans had an average serum B-12 level of 164 pg/ml; the control group (standard Western diet) had an average serum B-12 level of 400 pg/ml. The difference between the two groups was significant at the 0.001 level. 26 vegans (from a sample of size of 36, i.e., 72.2% of vegans in the sample) had B-12 levels below 200, the lower limit of the normal range [Bar-Sella et al. 1990, p. 310]. None of the vegans displayed hematological defects (i.e., signs of anemia); however, 4 vegans with B-12 levels below 100 had neurological symptoms. Three of the four (with neurological symptoms) were followed, and they all showed clinical improvements in symptoms after intramuscular (injected) vitamin B-12 supplementation.

  Crane et al. [1998] studied the vitamin B-12 (cobalamin) status of two vegan families. The individuals studied had been vegans for 2-21 years. Their study is noteworthy for two reasons. First, it was very thorough and included tests for levels of homocysteine, methylmalonate, and several other factors involved in B-12 metabolism. Second, it discusses the use of oral B-12 supplements, and recommends that B-12 supplements be chewed, rather than swallowed whole, for best absorption.

  Crane et al. [1998, pp. 87, 88] note:

  Results showed that if the data of the serum CBL [cobalamin, vitamin B-12] and urinary MMA [methylmalonic acid] are combined, all nine of the [study] subjects had chemical evidence of insufficient CBL [i.e., deficiency]...

  Evidence, which we have reported elsewhere (Crane et al., 1994) indicates that over 80 per cent of those people who have been vegans for two years or more are deficient in CBL...

  Only one person in the study showed possible symptoms of deficiency, which were alleviated by oral B-12 therapy. However, five of the test subjects showed mild signs of anemia.

• B-12 levels in lacto-vegetarians. In contrast to the low B-12 levels reported in vegans, B-12 levels in lacto-vegetarians appear to be closer to normal. Dong and Scott [1982], discussed above, tested lacto-vegetarians; see table above for serum B-12 values observed. Solberg et al. [1998] analyzed the plasma B-12 levels of 63 long-time Norwegian lacto-vegetarians, and found no significant differences when compared to a control group (standard Western diet). An interesting side point in the Solberg et al. [1998] study is that lacto-vegetarians who took B-12 supplements had plasma B-12 levels equal to the lacto-vegetarians who did not take supplements. [Note: this should not be interpreted as suggesting that oral cobalamin supplementation is ineffective. Quite to the contrary, an excellent recent study, Kuzminski et al. [1998] has found oral cobalamin therapy to be more effective than intramuscular (injected) cobalamin therapy.]

However, a retrospective and analytical review of Immerman [1981] shows that his assessment criteria are logically flawed, and there may be bias present in his review. A summary of the flaws in Immerman's review is as follows.

• Review criteria admitted only long-term deficiencies (a logical fallacy). Criteria 2 and 4 of Immerman require low serum levels of B-12, plus the presence of (i.e., diagnosis that includes) anemia and/or subacute combined degeneration (SCD). The problem with such narrow criteria is that the symptoms specified are serious long-term symptoms only; see Herbert [1994] for a discussion of the staging of B-12 deficiencies. For example, requiring a diagnosis of subacute combined degeneration means that milder neurological impairments are ignored (mild B-12 deficiency might not produce anemia or SCD.) Hence, it appears that Immerman's requirements can be met only by serious, advanced cases, and he may be rejecting perfectly good data--a major statistical and logical fallacy that renders his conclusions invalid.

• Review criteria required non-standard therapy for B-12 deficiency. Criterion 5 of Immerman requires that the B-12 symptoms be reversed by oral administration of 1 mcg of B-12 per day. To those who are not acquainted with standard treatment protocols for B-12 deficiency, this may seem reasonable. However, those acquainted with the issues involved in cobalamin therapy will immediately recognize criterion 5 as unrealistic and deceptive.

  Since the late 1950s, the standard method of treatment for B-12 deficiency in the U.S. has been via intramuscular injections (see Hathcock and Troendle [1991, p. 96] and Lederle [1991]), and not via oral cobalamin as Immerman appears to require. Indeed, Immerman appears to be so rigid in his evaluation of the studies that he objects to one study that administered 5 mcg B-12 (and one unit of blood) to a patient.

• Review criteria called for symptom relief on an inadequate dose of B-12. Such rigidity is actually deceptive because the absorption rate for oral cobalamin in pernicious anemia is approximately 1.2% [Berlin et al. 1968, as cited in Lederle 1991]. Hathcock and Troendle [1991] report that oral doses of 80-150 mcg per day are helpful but do not restore cobalamin serum levels to normal. Lederle [1991] notes that some early studies reported poor results from oral doses of 100-250 mcg of cobalamin per day. Oral doses of 300 to 1,000 mcg per day have proven effective for treatment of pernicious anemia; see Hathcock and Troendle [1991] for citation of 5 relevant studies.

  Now let us consider Immerman's criterion 5--that is, strictly requiring an oral dose of 1 mcg per day--in light of the following facts.

  • B-12 (cobalamin) RDA of ~2 mcg/day.

  • An approximate absorption rate of 1.2% for oral cobalamin in pernicious anemia cases.

  • The review criterion of 1 mcg oral B-12 per day is not supported by reference cited in review. Immerman cites Chanarin [1969, pp. 40-63, 708-714] as the reference for criterion 5. However, Chanarin [1969] states that 1 mcg B-12 per day is insufficient (p. 57), recommends oral administration of 5-10 mcg B-12 per day in cases of deficiency (p. 712), and cites two studies: Schloesser and Schilling [1963], and Winawer et al. [1967], which reported no or suboptimal improvement on oral doses of 1 mcg B-12/day. Thus it appears that Chanarin [1969] does not support Immerman's criterion 5.

  • More recent studies indicate that daily oral doses of 5-20 mcg/day (i.e., higher than the dose specified by Immerman) without intrinsic factor may be ineffective; see Lederle [1991] for two relevant citations.

  • Standard treatment (U.S.) for B-12 deficiency has been via injections rather than oral cobalamin.

  We conclude, then, that Immerman's criterion 5 requires symptomatic relief from what appears to be an insufficient dosage of cobalamin, administered in a non-standard way (orally vs. injections). This leads to the conclusion that Immerman's criterion 5 is unrealistic and deceptive, and thus is a logical fallacy that renders his conclusions invalid.

• Rationalizations and bias in review? A review of Immerman [1981] suggests he grasps at every possible rationalization in an attempt to avoid facing the simple reality that if inadequate amounts of vitamin B-12 are ingested, a deficiency may result. Some may interpret such rationalizations as suggesting possible bias. While it is certainly possible for a vegetarian to be deficient in B-12 due to factors unrelated to diet, to try to rationalize away all B-12 deficiencies in vegetarians via non-diet reasons makes the issue of bias relevant here.

• Immerman actually did not address one of the most important issues regarding older B-12 studies: the assay methods used and their reliability (i.e, some of the older assay methods are unreliable). For more on this point, see the following subsection on "B-12 in spirulina and other plant foods" just below.

[Note: Despite the risk or reality of belaboring the point here, I have discussed Immerman [1981] at length because it is occasionally cited by raw/veg*n diet advocates who wish to discount the published studies showing B-12 deficiencies in veg*ns, and/or deemphasize the importance of B-12 in veg*n diets.]

Steer clear of dietary extremists who rationalize B-12 deficiency concerns. The above evidence of apparent vitamin B-12 deficiency in vegans (both raw and conventional) should serve as a warning to fruitarian/veg*n extremists and their followers who claim adequate vitamin B-12 can be obtained by eating unwashed plant foods or from intestinal bacterial synthesis (the latter topic is discussed later herein).

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(Is Vitamin B-12 Available from Spirulina or Intestinal Synthesis?)

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SEE TABLE OF CONTENTS FOR:
PART 1 PART 2 PART 3 PART 4 PART 5 PART 6 PART 7 PART 8 PART 9

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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?

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