>What do you mean by following the allopathic model? I'm confused. My
>understanding is that B12 analogues are not absorbed by the cells. What model
>are you referring to that shows something different?
>
>Love, Liza
That is exactly what I mean, that .
The 1989 RDA says "Plant foods are essentially devoid of vitamin B12
except for adventitious inclusion of microbially formed B12 in soil or
water." (page 159).
While the following may be tedious, some of it is quit interesting.
Lisa Walford
(quoted from a newsgroup post with permission of author.)
I recently got a copy of
Vitamin B-12: plan sources, requirements, and Assay, by Victor
Herbert, American Journal of Clinical Nutrition 1988 vol. 48 pp 852-8
Several interesting points for vegans out there. Do not read this
email during lunch. :-).
1. It takes ~20 years for genetically normal humans who consume too little
vitamin B12 to show symptoms of deficiency. Normally B12 is
continuously excreted and reabsorbed in the upper GI; abnormal
humans who cannot absorb or reabsorb B12 become deficient in only 3 or so
years. "Careful studies from England on several hundered vegans
showed that they all eventually get vitamin B-12 deficiency
disease...". The reference is Chanarin et al; Megaloblastic anemia
in a vegetarian Indian community. Lancet 1985; 2:1168-72.
2. It is quite clear that humans cannot absorb the B12 synthesized by
bacteria in the gut. The experiment was quite clever -- take a
bunch of vegans who are vitamin B-12 deficient, and feed them their
own stools suitably processed for palatability and (I assume) to
prevent disease risk. The B12 deficiencies go away. I'm not
joking. The original reference is: Callender ST, Spray GH.
Latent pernicious anemia. Br. J. Haematol 1962;8:230-40.
3. In a study of a group of Iranian vegans who did not get vitamin B12
deficiency, it was discovered that they fertilized their plants with
their own excrement and did not wash them perfectly. Same result
as item 2, but in a natural setting. Reference is the same as item
1 above.
4. The US Pharmacopeia assay for vitamin B12 is simply wrong. It
actually measures the total amount of B12 plus some non-B12 analogues
that are not useful for human metabolism. Tempeh and spirulina
contain lots of the useless analogues but not significant amounts of
true B12, for instance. The paper doesn't mention
seaweed. On first principles one would expect the flawed assay to
correctly measure animal sources of B12, such as milk and meat. It
is also safe to get B12 from suppliments.
JN: JOURNAL OF THE AMERICAN DIETETIC ASSOCIATION, 1995, Vol.95,
> No.2, p.180
> IS: 0002-8223
> AB: Objective To compare nutrient intakes between vegetarians and
> nonvegetarians with similar health practices, and to assess
> relationships with eating behavior scores from the Three-Factor
> Eating Questionnaire.
> Design Survey.
> Setting Metropolitan area in western Canada.
> Subjects Subjects (n=45) were participants in a study comparing
> subclinical menstrual disturbances between vegetarians and
> nonvegetarians. To be included, women had to be 20 to 40 years
> old, be weight stable with a body mass index (BMI; kg/m2) of 18
> to 25, be a nonsmoker, exercise 7 hours a week or less, consume
> one alcoholic drink or less a day, and not be using oral
> contraceptives. Nonvegetarians (n=22) ate red meat three times
> a week or more, and vegetarians (n=23, 8 vegans and 15
> lactovegetarians) had excluded all meat, fish, and poultry for
> 2 years or more.
> Main outcome measures Nutrient intake assessed by three 3-day
> diet records; supplement use; body composition; and dietary
> restraint (conscious limitation of food intake), disinhibition,
> and hunger assessed by the Three-Factor Eating Questionnaire.
> Statistical analyses performed Anthropometric variables,
> nutrient intakes, and eating behavior scores were compared
> between vegetarians and nonvegetarians using unpaired t tests,
> and among vegans, lactovegetarians, and nonvegetarians using
> one-way analysis of variance and Duncan's test. Supplement use
> was compared using chi2 analysis. The Pearson correlation
> coefficient was used to evaluate relationships between
> variables.
> Results Diets of all women adhered closely to current nutrition
> recommendations. Vegetarians had lower protein and cholesterol
> intakes and higher percentage of energy as carbohydrate, ratio
> of polyunsaturated fat to saturated fat (P:S ratio), and fiber
> intake than nonvegetarians. Vegetarians had lower riboflavin,
> niacin, vitamin B-12, zinc, and sodium intakes and higher
> folate, vitamin C, and copper intakes. However, many
> differences were not apparent between the subgroup of
> lactovegetarians and nonvegetarians (their P:S ratios and
> carbohydrate, fiber, riboflavin, folate, vitamin C, and copper
> intakes were similar). In contrast, differences existed between
> the lactovegetarian and the vegan subgroups. Supplement use was
> similar between groups, except for greater vitamin C use by
> vegetarians. Vegetarians were leaner than nonvegetarians, had
> lower restraint scores, and had significant associations
> between restraint and BMI (r =.49; P<.05) and energy per
> kilogram body weight (r=-.60; P <.01).
> Applications/conclusions Current nutrition recommendations can
> be attained by vegetarians and nonvegetarians alike, but
> nutrient intakes cannot be inferred from dietary pattern. In
> this study, the intakes of health-conscious nonvegetarians and
> lactovegetarians were more similar than the intakes of
> lactovegetarians and vegans. Vegans' calcium and vitamin B-12
> intakes may need attention. Vegetarians' lower restraint scores
> suggest that they are not at increased risk for eating
> disorders.
At 11:39 AM 4/29/98 EDT, you wrote:
>Lisa Walford:
><< If you follow the allopathic model, then B12 analogues are simply not
>absorbed in the body at all. >>
>
>What do you mean by following the allopathic model? I'm confused. My
>understanding is that B12 analogues are not absorbed by the cells. What model
>are you referring to that shows something different?
>
>Love, Liza
>
>[log in to unmask] (Liza May)
>
>
Lisa Walford [log in to unmask]
www.walford.com longevity, nutrition, diet software
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