From: altar@beaufort.sfu.ca (Ted Wayn Altar)
Subject: Re: vegan sources: B12, D3 and iron
Organization: Simon Fraser University, Burnaby, B.C., Canada
Date: Sun, 30 Aug 1992 10:14:49 GMT



>Query:  does anyone know of good vegan sources of vitamin B12?
>Vitamin D?  Iron?

>I know Maypo oatmeal and grapenut cereal in the U.S. are fortified
>with B12 and iron.

>I'm aware I can take supplements for all three, but I've noticed many
>B12 supplement pills have something like 8-100 times what you really
>need per day.  Isn't too *much* B12 supposed to be bad for you?


Two general remarks.  First, I think multi-vitamin supplements
are not really needed by most healthy adults and they are simply
an expensive way to make one's urine a brilliant yellow.  Indeed,
such supplements can be dangerous (e.g., see posting below about
D).  If you must take supplements, choose individual supplements.

Second, people it seems to me worry far too much about whether or
not they are getting enough vitamins/minerals and their resorting
to food charts can be very misleading.  Things, like food
composition and interactions betweem nutrients, are far too
complex for food charts to take into account.  In the end it may
simply better, and certainly more simplier, to ensure that one is
eating a variety of good foods, and foods of good quality.  For
instance, most people simply do not eat enough fresh fruits and
vegetables, especially vegetables (as a rule of thumb, one should
consume at least 2 lbs of fruits and vegetables per day).  Having
said that, let me try to answer your question.

I've reposted two of my earlier postings; one
pertaining to B12 and the other to vitamin D.  See this latter
posting for an answer to your query about vitamin D.



B12

It is NOT a good idea to take B12 daily, simply because your
ability to absorb B12 will decrease with such a surfeit of
available B12.  The end result is that you simply become overly
dependent on B12 supplements.  Maybe there is no harm in this,
but it is an unnecessary expense.

In any case, the best evidence to date is from prof. Victor
Herbert (a leading authority on B12) who has established  that
normal individuals only need .1 microgram  per day absorbed from
food.  The higher RDA recommendation of 3.0 micrograms/day is
excessive so as to ensure a margin of safety that includes
individuals with possible minor absorption problems (remember,
over 95% of cases suffering from B12 deficiency is due to
physiological absorption problems, not inadequate intake).  The
body can store B12 for remarkably long periods of time (from 3 to
5 years) and due to the fact that we can reabsorb B12 secreted by
the bile each day (the main source of loss), the amount of time
it would take to run out is about 10 to 30 years. So, there is
simply no need to consume B12 supplements every day or even every
week or every month.  One one-half of one of those typical 1000
mcg pills every 6 months or even once a year would be adequate.
After all, you are getting B12 from other sources.

For example, there are trace amounts in some root vegetables (at
least on the surface if you don't over scrub your vegetables) and
their is good evidence that the b12 which bacteria in our mouth,
throat, nasopharynx, around the tonsils and tonsillar crypts, in
the folds at the base of the tongue, upper bronchial tree, and
the even the small intestine itself where it is absorbed.  Up to
.5 mcg at may be obtained this way.

B12 is really only a concern for vegan infants, vegan lactating
or vegan pregnant woman and for the elderly (vegan or not) since
the capacity to absorb B12 diminishes with age.  Hence, as a
healthy vegan (a lacto-ovo- vegetarian need not worry at all)
there should be no need of B12 supplements, but if you want to
play it extra safe then by all means take the occasional 500 mcg
B12 supplement once or twice a year.  Also, remember to ensure
that the exogenous source is bacterially produced and is not
spirulina or nori (these algae sources of B12 were once thought
to be useful sources, but they now are thought to only produce
analogues and not true B12 that actually interfere with the
absorption of true B12).

I have included below my earlier summary about B12 where I
discuss the above in more detail and provide references for you
to check you my information.  Hey, no need to  take my word for
it.



IRON

With respect to iron, here you should be more cautious you should
be more cautious about supplements.  Iron anemia is generally not
a problem for men but it is a serious and widespread problem for
women, vegetarian or not.  Indeed, with respect to actually full-
blown iron anemia both vegetarian and non-vegetarian women are at
about the SAME risk.

In general, women need twice the amount of iron as do men
(pregnant woman even several times more than an adult male) but
too much iron for men becomes toxic.  Hence, the recommendation
to lace everybody's flour with iron was a bad one simply because
one half of the population (i.e., women) would benefit while the
other half would be at a greater risk of iron toxicity
(especially if these men also drink alcohol).

Iron anemia is the most common nutrition deficiency in humans,
affecting in particular young children and girls/women of
childbearing age.  The problem lies essentially with the fact
that most foods are relatively low in iron and if even plenty of
iron is available in a meal the body will only absorb between .3
to .4 mg/day at most.  It simply doesn't matter how much iron is
present in the gut, you can only absorb so much.  Now, within
this range of .3 to .4 mg/day absorption will vary according to
bodily need.  Absorption can rise to 3 or 4 mg/day when the body
is depleted or near depleted and can fall to .5 mg/day or less
with iron stores are high.  Hence, a relatively low intake of
iron could be just as adequate as a high on, since the body will
compensate -- within limits -- to that lower intake.  The
important thing is to ensure that at least a DAILY intake occurs,
even if it is low.

Good sources are in rank order are:
     black strap molasses
     dried legumes
     nuts and seeds
     dark-green, leafy vegetables,
     dried fruits
     whole grain breads and cereals
     fruits.

Also, it is very important to observe that iron absorption is
greatly facilitated towards it upper maximum by the addition of
VITAMIN C in your foods.  Hence, dark-green, leafy vegetables and
fresh fruits are good sources since their total absorbable iron
is increased by the presence of vitamin C.  For example, 60 mg of
C with a meal of rich more than tripled the absorption of iron.
Adding the equivalent amount of C in one papaya enhanced
absorption of iron from corn by fivefold.  Besides ascorbic acid
(vitamin C), citric acid and lactic acid also promote absorption.

Contrariwise, it is also important to remember that dietary items
like tea (tannates), coffee, most phytates (not all), phosvitin
in egg yolks, calcium phosphate salts, and EDTA (a preservative
used in a number of food products) will inhibit the absorption of
iron.  Drinking coffee and tea at every meal is not going to help
one's dietary iron absorption.

Now, while iron toxicity is far less prevalent compared to iron
anemia this problem is problem is not to be ignored and it is
particularly serious to about 3/10,000 who possess a special
genetic susceptibility to iron overload (these can be identified
by screening tests).

A lot more can be said on this topic and maybe I'll post more at
some future date.



B3 (niacin)

Good sources include (percentage of recommended allowance for
adult woman 23 - 50 years old provided by 3.5 ounces):
     peanuts                           131%
     sesame or sunflower seeds          42%
     Mushrooms                          32%
     lettice                            32%
     almond                             25%
     millet, bulgur or peas             18%
     pinto beans                        17%
     kale                               16%
     corn, collard or cashews           13%
     potato or avocado                  12%
     rice                               11%
(from USDA and Ford Heritage, reprinted in Akers, 1989)

Undesirable effects from niacin from overdoes via supplements
include (1) release of histamine (2) possible injury to the liver
(3) raising serum uric acid levels (4) dermatological problems
(5) elevation of plasma glucose levels.



Ref:
Hunt & Groff (1990).  Advanced nutrition and human metabolism
Keith Akers "A Vegetarian Sourcebook", 1989

Newsgroups: rec.food.veg