From: abulsari@abo.fi (Abhay Bulsari VT)
Subject: Food for a future and Vitamin B12
Organization: Abo Akademi University
Date: Tue, 15 Sep 1992 06:46:40 GMT


From: Michael Traub <traub@btcs.bt.co.uk>



Food for a Future by Jon Wynne-Tyson, published 1979 by Universe Books,
381 Park Avenue South, New York, N. Y. 10016, U.S.A.

pages 110-111, footnote page 114:

It  is  interesting  and possibly very relevant that lifelong vegans seldom
suffer  from  B12 deficiency. Where deficiency has been established, it has
been  mostly  in  people  who  have  switched, perhaps too abruptly, from a
diet  based  on  animal  products.  This has helped to prompt the suspicion
that  as  children brought up from birth on a vegan diet are able to absorb
the  B12  made  by  the  bacteria  in  their  colons,  it  may  be that the
perversion  of  the  body's  chemistry  through  meat  eating  has  made it
impossible  for  a  small  number  of  people to switch to the more natural
vegan diet later in life without showing signs of B12 deficiency. (2)

This  is  not  to say, of course, that symptoms due to inadequate intake of
B12  are  not  to  be  found in malnourished people the world over, whether
they   are  omnivorous  or  more  selective  in  their  eating  habits.  An
inadequate  diet  will  be  deficient  in a great many elements, whether or
not  meat  is included. Although volumes have been written about B12, it is
in  our  knowledge  of man's adaptational abilities that we have far to go;
the  uncertainties  surrounding  a  clearly inadequate intake (irrespective
of absorptional capacity) are less in dispute.

It  is  known that the bacteria in the human colon synthesise B12, but that
in  most  cases this is not available for absorption by the large intestine
because  the  absorption  takes  place  in  the  lower end of the ileum (or
small  intestine).  This  absorption  depends  upon  the  presense  of  the
'intrinsic  factor',  a  protein-like substance produced in the stomach. In
the  case  of  pernicious  anemia,  for  instance, this intrinsic factor is
absent.  There  is  some  evidence  that  the large intestine of vegans can
absorb  B12  (Ellis,  F.R.;  Wokes,  F.,  'Vitamin  B12', the Vegan, Winter
1966/67)  -  a  point  that  may  well be given more prominence as research
continues.

(2)  to  put  the horse more squarely before the cart, there is a good deal
of  support  for  the  theory  that  man lost his ability to manage without
dietary  B12  when  he  took  to  meat  eating,  which caused the bacterium
Escherichia  coli  to  move further down his intestinal tract to beyond the
point  at  which  B12  could  be  absorbed  (see  A. G. Long and F. Wokjes,
'Vitamins  and  Minerals  in Plants', Plant Foods for Human Nutrition, Vol.
1,  No.  1,  May  1968). The upward movement of the Escherichia, it may be,
is  encouraged  by  a  return  to that vegan pattern we abondoned. However,
the  inner  reaches  of  our guts are not of universal fascination and most
of   us   prefer  to  leave  the  problems  of  bacterial  balance  to  the
scientists.  I  must  leave  it  to  the  relaly keen reader to explore for
himself in greater depth.

-- 
A. Bulsari                                       Tel.  358 (21) 654 721
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