From: altar@beaufort.sfu.ca (Ted Wayn Altar)
Subject: B12 again
Organization: Simon Fraser University, Burnaby, B.C., Canada
Date: Sun, 30 Aug 1992 10:20:59 GMT

We seem to have some new readers and so I thought that it might
be helpful to re-posted an earlier message regarding B12.
If you have already seen this note, then you can conveniently
move on as I have not added anything new.

                                     ted



                                
                           Vitamin B12


 1.  Yeast, miso, tempegh, etc.

It is PARTLY true that cultured sources may have little or no
B12, but my understanding is that this depends on the culturing
process.  Yeast, for instance, if cultured under controlled
conditions so stringently that no bacteria is allowed to grow
along with the yeast, then indeed there will be no B12, since the
only source in nature is from bacteria  (incidentally, I have
been told that the gene for B12 from bacteria could theoretically
be cloned onto nutritional yeast so that we could then not only a
tasty yeast but one with more than enough B12).

 2.  Spirulina and nori

Apparently, the problem with algae sources like spirulina or nori
is not only that they are low in what is being NOW measured as
B12 by newer methods (see Herbert, 1988), but that it may not be
a true B12 but possibly contains what has been referred to as
noncobalamin analogues of B12 that might actually interfere with
the absorption of true B12.  In any case, "B12" from spirulina or
nori, if it is true B12, is simply NOT bioavailable (see
Dagnelie, 1991).

     Herbert, V. (1988).  Vitamin B-12: plant sources,
requirements, and assay.  AMER. J. OF CLINICAL
NUTRITION, 48(3):852.

     Dagnelie et al. (1991).  Vitamin B-12 from algae appears not
to be bioavailable.  AMER. J. OF CLINICAL NUTRITION,
53:695.

Hence, if you are going to use supplements, make sure that their
source of B12 is from cultured bacteria (often they use a soybean
mash).  Simply phone up the local distributors of the product you
are interested in buying to check out how they obtain their B12.
Also, one probably does not need to take them very often since
the dosages (e.g., 1000-1200 micrograms) of these supplements
usually come in amounts far in excess of what is actually
required (see below).

 3.  Multiple causes of B12 deficiency

It should be noted that B12 deficiency is not an easy problem to
understand due to the numerous other nutrients and bodily
products that B12 interacts with.  Most familiar, of course, is
the so-called "intrinsic factor" manufactured by the stomach and
necessary to bond with B12 before it can be absorbed by the body.
As one gets older one might begin to produce less of this
"intrinsic factor".  Hence, the elderly, whether they be
vegetarian or not, are at a greater risk for B12 deficiency.
Other things that interact to decrease B12 metabolism include
folacin deficiency, iron deficiency anemia, B6 deficiency, oral
contraceptives, etc.  Hence, B12 deficiency can result from
causes other than a simple lack in the diet.

 4.  Recommended amounts of B12

 Now, the amount of B12 actually needed by the body is incredibly
small and the RDA level is of course more than you need, due to
considerations for a safety margin but also because of the
measurement problem for small amounts of B12 and the consequent
assessment of now much B12 is really necessary for human beings.
The National Research Council recommends 3 micrograms (3
millionths of a gram) per day to meet the body's needs.  Victor
Herbert, who is probably the leading authority on B12, puts the
actual requirements to be round .1 microgram/day (hence, the NRC
recommendation may well be some to 6 to 30 times greater than our
actual requirement).

The fact of the matter is that you need very little and your body
can store the stuff for 3 to 5 years.  Another fact is that
researchers really don't know how much B12 is in our foodstuffs
since their is not yet a sensitive enough assay for trace amounts
of B12.

 5.. Sources of B12

It has been reported that B12 is to be found on the roots and
stems of tomatoes, cabbage, celery, kale, broccoli, and leeks.
Victor Herbert, however, found that "well washed" plant foods
contain no B-12 except for trace amounts in some rhibozium-
bacteria-containing root nodules.

Maybe a more important consideration than what is to be found in
our foods is that much vitamin B12 is actually produced by the
body itself.  Bacterial flora in the gut, but also bacterial
growth in the mouth, around the teeth and gums, in the
nasopharynx, around the tonsils and tonsillar cypts (another
reason not to remove tonsils if possible), in the folds at the
base of the tongue and even in the upper bronchial tree can
produce B12.

 6.  Are vegans at a greater risk of B12 deficiency?

Vegetarians who are not vegans but still consume milk products
and eggs, probably not need to worry about B12 deficiencies.

Indeed, it is not evident that sensible vegans, especially
adults, actually suffer from a greater incidence of B12
deficiency than do omnivores.  If one eats a variety of food
products, consumes fresh vegetables and is not on antibiotics,
then the B12 being produced by bacteria in the gut and the trace
amounts from foods is probably sufficient.  The direct evidence
for this comes from those studies that have actually tested
vegans to see if B12 deficiencies turn up.  In general, the
results uniformly indicate that even in the case of those vegans
who for decades have not taken any supplements they still appear
to have adequate B12 levels.  While the serum levels of B12 tend
to be lower than that of an omnivorous control group, hematologic
evidence of vitamin B12 deficiency is not present.  Given what
conservative authorities have to say in theory about B12
(especially those that would undertake an analysis of the
composition of a vegetarian diet), we should expect to see a
greater incidence of B12 deficiency in vegans than in non-vegans,
yet there is no such difference as far as I know.

Of course, people will cite some case studies of some unfortunate
vegans but such case studies are limited in that we don't have a
proper comparison with non-vegans and by now it should be
apparent that many other causes besides dietary deficiency can be
at fault.  If one looks at these case studies closely, the
individuals are often reported as having other deficiencies
thereby undermining the very point that such cases might thought
to have illustrated in the first place.

Now, there is a concern for the children of some fad vegetarians
that should be seriously noted.  There is enough evidence (see
references below) to here warrant concern that at least some
vegetarian groups do incur a risk of B12 deficiency among their
young children.  In particular, vegetarian groups prone to
certain "fad" vegetarianism like that of macrobiotic or crudivore
diets, seem to sometimes (not consistently) have a higher
incidence of B12 deficiencies among their young children.  Why
certain vegetarian diets or practices seem to incur this problem
is not yet understood.  The heavy use of nori, for instance,
could be one explanation.  To err on the side of caution, then
lactating vegetarian women and young vegan children should
probably take some supplements.  The Nutrition Standing Committee
of the British Paediatric Assoc recommended in its special report
on vegetarian weaning (ARCHIVES OF DIS. IN CHILDHOOD, 1988,
63:1286), for instance, recommended B12 supplements at weaning
and for breast feeding vegan mothers.

                                             ted

 7.  References 1:  Group comparison studies involving adult
vegetarians.

Bar-Sella et al. (1990).   Vitamin B12 and folate levels in long-
term vegans.  ISRAEL JOURNAL OF MEDICAL SCIENCES.      26(6):309

Ernst et al. (1986).  Blood rheology in vegetarians.  BRIT. J. OF
NUTRITION, 56(3):555.

Sanders et al. (1977).  Haematological studies on vegans.  BRIT.
J. OF NUTR., 40:9

Wokes et al. (1955).  "Human dietary deficiency of vitamin B-12.
THE AMER. J. OF CLIN. NUTR., 3(5):375

Smith (1962).  Veganism, a clincal survey with observations of
vitamin B-12 metabolism.  THE BRIT. MED. J, 1(June 16):1655.

Ellis & Montegriffo (1970).  "Veganism, clinical findings and
investigations.  THE AMER. J. OF CLIN. NUTR., 23(3):249.

 8.  References 2:  Studies involving some vegetarian children
indicating the presence of B12 deficiency.

Dagnelie it al. (1989).  Increased risk of vitamin B-12 and iron
deficiency in infants on macrobiotic diets.  AM. J. CLIN. NUTR.,
50:818.

Dagnelie et al. (1989).  Nutritional status of infants on
macrobiotic diets aged 4 to 18 months and matched omnivorous
control infants: a population-based mixed-longitudinal
study.  Weaning pattern, energy and nutrient intake.  EUR.
J. CLIN. NUTR., 43:311.

Chanarin et al. (1985).  Megaloblastic anaemia in a vegetarian
Hindu community.  LANCET, 2:1168



 It would seem that interest in this topic of B-12 is quite
extensive, which is probably a good thing since this is probably
the most widely held up "disadvantage" with a vegan diet, a diet
that is otherwise so wholesome and advantageous in every other
way.  Maybe because it is the only apparent "flaw" of a vegan
diet that so much fuss is made about it.  Indeed, much wailing an
gnashing of incisors by our omnivorous critics is something all
vegans must contend with and patiently tolerate.  :-(

 A.  SYMPTOMS OF B-12 DEFICIENCY

Too often the descriptions of symptoms in some reference texts is
drawn from information written from the perspective of medical
practitioners who have access to test results and who are going
to rely heavily on such results.  For us lesser mortals, all we
have is our own experiential (phenomenological) "feel" of
wellness or not.  This is not to be discounted since it is such
feelings of a `lack of wellness' that brings us to seek medical
advice in the first place, or motivates us make important life
changes.

For a practical, non-laboratory symptomatology of B-12
deficiency, the following by Thrash & Trash (1982) is quite good:

      "The pernicious anemia patient was first described in the
     medical literature in 1849 as one who appeared pale and
     sallow with a shiny tongue and complained of weakness and
     fatigue that progressed gradually to the point of paralysis.
     Blood tests done on such patients today would reveal low
     hemoglobin levels and large, pale red blood cells.  In the
     early stages of the illness there are numbness and tingling
     in the hands and feet with a loss of sensation.  Gradually a
     lack of motor coordination develops.  These symptoms are now
     known to be due to an inability to synthesize myelin, the
     fatty sheath that insulates nerve fibers.  As a result, the
     nerves to the limbs degenerate.  If allowed to proceed
     unchecked, the deterioration progresses into the spinal cord
     and ultimately to the brain.  Moodiness, poor memory, and
     confusion give way gradually to delusions, hallucinations,
     and overt psychosis."

Now, with respect to the psychological/psychiatric symptoms, the
following might be of some use, albeit it is more jargonistic:

      "Psychiatric symptoms attributable to vitamin B-12
     deficiency have been described for decades. The earlier
     reports are for the most part in accord with more recent
     ones, despite being diagnostically less specific in
     psychiatric and hematologic terms. These symptoms seem to
     fall into several clinically separate categories: slow
     cerebration; confusion; memory changes; delirium, with or
     without hallucinations and/or delusions; depression; acute
     psychotic states; and (more rarely) reversible manic and
     schizophreniform states.
          From Hector & Burton (1988)

Note that we are talking about what APPEARS to be schizophrenic
states, but of course we don't have here true schizophrenia,
hence the term "schizophreniform states".

No doubt, some of our defensive omnivorous critics might think in
their meaner moments that this mental deterioration describes all
of us vegetarians.  :-)

 CAUSE FOR PANIC?

Let it again be said, however, that B-12 deficiency is "rare"
among vegans and that over 95% of deficiency problems are NOT due
to a simple intake inadequacy but are due to an MALABSORPTION
problem.  The development of a serious B-12 deficiency is not a
simple or well understood matter but it is known that absorption
and conservation of B-12 in the body is more important than how
much is to be found in the diet.

Known causes of malabsorption are a lack of intrinsic factor
(e.g., due to pernicious anemia, destruction of gastric mucosa,
etc.), removal or disease of the second portion of the ileum,
competition for B-12 by microorganisms or intestinal parasites,
toxic substances, etc.

Beside malabsorption, there are also possible problems (see
Herbert, 1973) in UTILIZATION (e.g., enzyme deficiencies, liver
or kidney disease, etc), INCREASE LOSS (e.g., renal disease) or
for an INCREASE REQUIREMENT (e.g., hyperthyroidism, lactose
intolerance).

Still, if one has an absorption, loss, or increase need problem,
then presumably when little B-12 is available in the diet then
still less is going to be assimilated.  Now, what can we do to
prevent a B-12 deficiency?

 PRACTICAL RECOMMENDATIONS:

1.  REDUCE ONE'S NEED FOR B-12:

Before we consider increasing our intake of B-12 via supplements
we should first consider minimizing those conditions that might
make for an unusual requirement of large quantities.  Assuming
that one is in normal health (e.g., no intestinal parasites,
etc.), then below are some of the lifestyle conditions that can
unduly increase one's need for B-12 (adapted from Thrush &
Thrush, 1982):

     1.  The body can become habituated to large quantities of
          vitamin B-12.  Hence, some caution about megadoses of
          B-12 should be considered.
     
     2. Meat or other animal products and refined carbohydrates
          (sugars) when used generously may more than double B-12
          needs.
     
     3.  Persons who use drugs, chemical, or beverages which
          destroy B-12 (e.g., tobacco, alcohol, caffeine, etc.)
     
     4.  Megadoses of vitamin C may produce B-12 deficiency by
          destroying the cobalamins during transport through the
          gastrointestinal tract (Hines, 1975).  Quantities more
          than 1/2 of a gram can destroy 50% to 95% of B-12 in
          the food.
     
     5.  Oral contraceptives are used (affects the B-12 binders
          of the blood).
     
     6.  egg albumin and egg yolk decrease B-12 absorption



2.  INCREASE NATURALLY OCCURRING B-12 IN THE DIET.

Fresh garden pricked vegetables, particularly root vegetables,
that are not overly scrubbed cleaned or pealed will have some B-
12 on their surface.  Boiling such vegetables and then throwing
out the water would make for a loss of this B-12.

Since B-12 is predominantly produced by bacteria (no animal
produces its own), then foods grown in soils where the bacteria
flora is rich would presumable have more B-12 on their surface.
Hence, organically grown foods will probably be richer in B-12.

There is now some recent evidence (Combs, 1991) that some peas
and bean actually produce their own B-12.  It was previously
thought that the only source in nature was bacteria.  This would
suggest that such peas and beans would have their B-12 throughout
rather than just on the surface.  Still, this probably will not
suffice as a single plant source to provide sufficient B-12.

A simply but useful recommendation is to chew one's food properly
and leave plenty of time between meals helps absorption.  The R-
binders in saliva help to hold onto the B-12 in the food until it
reaches the small intestine where it absorbed (Fleming, 1978).

 3.  TAKING SUPPLEMENTS.

MULTIVITAMIN preparations containing B-12 is probably NOT a good
idea.  Besides consuming so-called vitamin "D" which most people
do not need and which has been implicated in helping to cause
arteriosclerosis and osteoporosis, these preparations contain
breakdown products of B-12 that can actually have an anti-B-12
effect.  Hence, these multivitamins may contribute to the very
deficiency that they were supposed to correct.  Victor Herbert
(1962), the leading authority on B-12, reported that all of the
10 multivitamin-mineral products that he tested showed anit-B-12
breakdown products.  Tests for B-12 in the blood unfortunately
cannot discriminate between the true vitamin B-12 and its
breakdown products.

For healthy adult vegans I do think we should be careful about
recommending routine B-12 supplements.  Even though complete
absorption is not likely, the dosages are probably still too high
(1200 mcg).  There is some case studies and experimental evidence
that an excessive B-12 consumption encourages cell division in
general and certain tumor cells in particular (Bergevin et al,
1976; Chauvergne, 1970).

If I may here voice a more personal opinion, I do think we should
be cautious and hesitant about over-consuming vitamins.  There
are no miracle foods or pills that can undo a sedentary life, bad
living habits and a junk food or fatty diet.  I find it sad to
see people spending so much money on vitamin pills and yet
begrudging a few pennies to buy fresh fruit or oganic produce.
Also, there is this misplaced notion that if a little works or is
good for you, then more is automatically better.  Our society as
a whole is badly skewed by this over-rating of quantity over
quality.

Frankly, I think that if one is in good health and eats quality
foods, then vitamins are simply not necessary and are a waste of
money.  The only benefit of popping multivitamin pills for most
healthy vegetarians, I suspect, is simply its placebo effect and
the enjoyment of seeing one's urine turn a brilliant yellow.
Having said this, however, there are exceptions, like  B-12 for
vegans and iron supplements for vegan women.  This does not
entail that all vegans MUST take these supplements, only that
there are common circumstances where they are most advisable.

In general, use of B-12 supplements should be considered by
pregnant and lactating women, young infants and children, the
elderly and vegans not in good health or who still smoke.  Serum
levels of B-12 are lower for smokers than non-smokers (this may
be an effect of the cyanide content of tobacco smoke, which the
body attempts to detoxify by a means that unfortunately uses up
the stores of B-12).

Non-smoking, healthy adult vegans who eat sensibly, are not on
medications (e.g., antibiotics) and who do not daily drink
alcohol probably do not need to take supplements.  If such vegans
are going to take supplements, then they should probably not take
them on regular basis since the doses are too high.  Remember,
individuals even on conventional diets (diets high in fat and
animal protein which increase the need for B-12) still only need
about .1 mcg per day according to Victor Herbert (recent revision
of RDA recommendations has lowered the amount from 3 mcg/day to 2
mcg/day).  Maybe half of a 1000 mcg pill no more than once month
would be more than sufficient.  Finally, make sure that your
supplements are derived from bacteria cultures and do not contain
spirulina or nori.

If one has been a vegan for a many years, it might be a good idea
to have one's serum B-12 levels checked.  The normal range is
about 150-750 pg/ml according to the Merck manual.  Others put it
at 140-900 pg/ml.  There is no exact cutoff.  Vegans, of course,
will have levels at the low end but this by itself is not a cause
for alarm.  After all, the "normal" range is based upon research
from an omnivorous population and vegans do have a lower need for
B-12 and are more efficient at preservation of extant stores.
Indeed, it could be argued that the "true normal" range might
well closer to that of vegans.  The ideal physiological
functioning has yet to be determined, but we do know that almost
all investigators reporting on vegans report them as being above
average in health and more active.  :-)

          ted

References:

I've already listed some of my primary sources in a previous
posting.  I have here drawn most heavily upon Thrash & Thrash
1982 and Combs (1991).  For further information about B-12 I
would highly recommend these books.  I would also recommend Keith
Akers (1989) chapter on B-12.  While the Thrash & Thrash book is
now 10 years old, it is at least written from perspective of two
MD's who are practicing vegetarians.  The Combs text is the
single best advanced book on vitamins that I have seen, although
it may be overly technical for most readers (as maybe all books
are at this level of scholarship).

Thrash & Thrash (1982).  NUTRITION FOR VEGETARIANS, 1982.

Combs, Gerald (1991).  VITAMINS: THEIR ROLE IN NUTRITION &
HEALTH.

Akers, Keith (1989).  A VEGETARIAN SOURCEBOOK: THE NUTRITION,
ECOLOGY, AND ETHICS OF A NATURAL FOODS DIET.

Hector & Burton (1988).  What are the psychiatric manifestations
of vitamin B-12 deficiency?  JOURNAL OF THE AMERICAN  GERIATRICS
SOCIETY.  36(12):1105-12,

Hines, J. (1975).  Ascorbic acid and vitamin B-12 deficiency.  J.
OF AMER. MED. ASSOC., 234(1):24.

Herbert, V. (1973).  The five possible causes of all nutrient
deficiency: Illustrated by deficiencies of vitamin B-12 and
folic acid.  AMER. J. OF CLIN. NUTRITION, 26:77.

Herbert, V. (1962).  Harmful B-12 breakdown products in
multivitamins?  MEDICAL WORLD NEWS, (Sept. 28):12-13.

Bergevin et al, (1976).  Pernicious anemia terminating in acute
myeloblastic leukemia.  SOUTHERN MEDICAL JOURNAL, 69:110.

Chauvergne, J.  (1970).  The risk of administering vitamin B-12
to cancer patients.  SEMAINE DES HOSPITEAUX PARIS 46:2170

Fleming, A. (1978).  Serum vitamin B-12 levels and vitamin B-12
binding proteins of serum and saliva of healthry Nigerians  and
Europeans.  AMERICAN J. OF CLIN. NUTRITION, 31:1732.


Response to critic:

The ability of vegans to absorb B-12 synthesized by their own gut
microflora is not to be so cavalierly dismissed.  Expert
researchers in this area certain don't preclude this possibility
(see my references to Victor Herbert.  Also see, "Contributions
of the Microflora of the Small intestine to the Vitamin B-12
Nutriture of Man" in NUTRITIONAL REVIEWS 38(8):247, Aug. 1980).

It is known that the B-12 is produced in huge amounts in the
colon (5.0 micrograms/day), though it doesn't seem that it can be
absorbed through the walls of the colon.  The small intestine,
however, can absorb B-12 and indeed some B-12 producing bacteria
is to be found there.  It is possible that enough intrinsic
factor enters the small intestine still sufficiently active to
bond with B12 for absorption. It is also possible that vegan
physiology enables a more ready absorption (or lower need?), than
theoretically expected.  Who knows?  What we do know that
people's ability to absorb some nutrients increases as one's need
for those nutrients increases.  For example:

     ". . . vegetarians appear to "undergo physiological
     adaptation enabling them to make somewhat better utilization
     of iron than would be expected from iron bioavailability
     studies involving the feeding of vegetarian diets to
     omnivores or involving the testing of particular components
     characteristic of vegetarian diets with omnivore subjects."
          (from Kies & McEndree "Vegetarianism and the
          bioavailability of iron" in Kies (ed.) NUTRITIONAL
          BIOAVAILABILITY OF IRON, 1982).

Hence, we must exert some caution in extrapolating the
nutritional needs and adaptive capacities of omnivores to that of
vegetarians.  Better, therefore, to look at the DIRECT evidence
of vegan health or deficiency.

And what does the "direct" evidence indicate?  It turns out, as I
earlier documented, that dietary vitamin B-12 deficiency is rare
among vegans, and we are here talking about vegans of many years
standing who never used supplements.  When B-12 deficiencies do
occur they are primarily the result of an inability, for whatever
reason, to ABSORB the vitamin (as we find in pernicious anemia).

Now, how is this empirical fact about long standing, non-
deficient vegans to be explained?  Maybe we can't at this point,
but theoretically, by your account, there should be a lot of
sorry looking vegans shuffling around.

Look, I don't wish to deter you or anyone else from taking B-12
supplements.  They certainly can't do any harm and one doesn't
have to take them that often.  Better to err, even if it is a big
error, on the side of caution.  Also, there are now plenty of B-
12 fortified foods.  What I don't like seeing disseminated
are unwarrantable assertions so strongly stated that no B-12
whatsoever can or is absorbed from the microflora of the gut.
There is good evidence to establish that this does occur,
debate now simply hinges on whether or not it is sufficient to
provide for the daily needs of a vegan.  The evidence I've
seen suggests that this is a likely biological possiblity, at for
vegans.

                                 ted