Jerry:
>As it is those with digestive disorders, or taking antibiotics need  to
>take B12, and if the signs of decifiency develope then they should take
>B12, but the truth is that we, actually not we, but normal flora in the
>colon, make B12 and we absorb it.

Jerry,  go to:

http://maelstrom.stjohns.edu/CGI/wa.exe?A2=ind9804&L=raw-food&P=R11633&D=0&H
=0&O=D&T=1

and you will find a message posted to raw-food by Lisa Walford
<[log in to unmask]> April 29, 1998.  Here are some passages from that
message:

        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.

Best, Peter
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