On Wed, 4 Nov 1998 13:07:19 -0500, Aaron D. Wieland
<[log in to unmask]>
wrote:

>
>According to Udo Erasmus, there isn't a single documented case of vitamin A
>toxicity, with the possible exception of some artic explorers who became
ill
>after eating a polar bear liver.
>
Altavista gives a bunch of information with +"vitamin a" +toxic*

For example:
>Since excess Vitamin A is stored, not excreted, continued long-term high
doses can have a toxic effect. Symptoms are similar to the
>symptoms for deficiency and included swellings over long bones, dry and
itching skin, nausea and diarrhea, fragile or brittle bones,
>fatigue or lethargy, bone and/or joint pain,
restlessness, and loss of hair. Additionally, excess vitamin A causes
reproductive
>problems including birth defects in the fetus and spontaneous abortion. It
is interesting to note that in humans, while high doses of
>vitamin A are toxic, high doses of beta-carotene are not as toxic.

That sounds a little like the heme/nonheme iron case with vitamin a
and
provitamins.
Pure Vitamin-A is stored and never excreted.
But on the other hand liver can be easily avoided.
Additionaly, liver of today is unfortunately also accumulating various
environmental
poisons like heavy metals (cadium, mercury...).

In Germany (and therefore probably in whole EU) it is forbidden to
sell
supplements with vitamin-a without a recipe
(so multivitamins don't contain it) for the reason of toxicity.

I've a book about paleolithicum where a hominid sceleton is mentioned
as a
proof
for early hominids meat consumption, because tha
t skeleton has the
described bone misformings caused by hypervitamin-a.
A liver-eating hunter...

There *are* reported cases in the USA, as reported at:
 http://prn.usm.my/bulletin/sun/1996/sun43.html
quoting:
>In the United States for example, approximately 10 to 15 cases of vitamin A
toxic reactions reported annually involve doses greater
>than 100,000IU per day. Chronic toxicity has been reported following
ingestion of 50,000IU daily for three months. Similarly,
>continuous consumption of 25,000IU to 50,000IU per day for periods of
several months or more can produce multiple adverse
>effects.
>Children may develop hypervitaminosis A with chronic doses of only 10 times
of the recommended dietary allowances for vitamin A.
>An example of such a case occurred in a one-year-old boy who received
6,000IU vitamin A daily for three months.

So we should better be careful with liver, although it i
s an extraordinary
plentiful source of some vitamins, and nearly a must for an adequate
vitamin-a supply if you don't eat much of carotene-containing plants.

regards

Amadeus