Hi all.
I cited:
>> >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.
Ilya wrote:
Amadeus, Aaron stated that,
except for those eating polar bear liver, there isn't
>a single documented case of vitamin A toxicity. You appeared to contradict
and
>gave examples of vitamin A toxicity symptoms, not of cases of toxicity. Do
you
>have examples of people (other than those eating polar bear liver) having
vitamin
>A toxicity from eating liver? (I am sure it's easy to OD on anything if its
available
>in pill form, that's why I am asking about toxicity cases from eating liver
or
>any other food, for that matter, with the exception of polar bear liver).

On the one report from '96 there were about 25 cases mentioned in the
USA
per year. I would assume that most of them developed by taking
supplements
because a quite small percentecage of humans tend to eat big amounts
of
liver
(especially because of the heavy metal danger).
However, I see no reason to assume,
why the vitamin-a from liver should be less toxic than

that of supplements.
Rather, in supplements they can switch to beta-carotene instead of
pure vitamin-a, which is reported to be less toxic for the same amount
of
IU's.

>> >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.
>How much liver (regular, not polar bear) would have to be consumed to equal
50,000IU daily for three
>months?
>USDA db gives 21000IU or so per 100gm. This means one would have to consume
over 1/2 lb of liver
>every day for months.
>For 100,000IU you'd have to consume over a pound.
My simple program gave for co
w's liver one day's recommendation at about 7 gram of liver.
The tenfold of a days recommendation at least resulted in the one
mentioned
case of an infant
to have toxicity problems after 3 months.
The statement with the 100000IU was for known cases of toxicity.
For pregnant woman and children much lower toxic doses were reported
to be dangerous.

However, as you computed it, for an adult male it should be possible
to eat a pound of normal liver for some months
each day (only thinking of the vitamin-a).

But for how many days? The key statement is IMO
"Since excess Vitamin A is stored, not excreted..."
That means the Vitmain-A will accumulate, even over the
years, so that you might reach the level of toxicity
after a long term intake which is only moderately over the
daily body's usage.

>On a related topic - I remember that Atkins put some of his patients on
rather large doses of
>vitam
in A for
>prolonged periods of time without any ill effects. Can't find the book (not
the diet one, but the
>nutrients
>book by him). If anyone has it, what were the amounts and for how long?
I have read much about *very* positive effects an adequate high supply
of vitamin A has. For cancer and many other health problems.
At 2 or 3-fold above the dayly rda, there is
probably no fear of toxicity.
I'd really advocate a vitamin-a supply in this dimensions.
If you don't eat very much of the famous "dark green vegetables",
then liver seems to be a very good source.

For inuit, additionally liver is the only good source of
some other vitamins the prey had accumulated in it's body.
Folic acid! I'd suppose the inuit to live at the upper limit of
bearable vitamin-a input, because they need liver for the supply
of some other vitamins. Maybe inuit even have a genetic program
which lessens the vit
amin-a toxicity (like with the w-3 fats).

For ice-age hunters a frequent intake over the years
nevertheless might have been dangerous if no adequate
usage rule or rite or taboo or whatever was established.
This is, why i assumed in my computation that they
*did* successfully obey some rules, and included liver.

Amadeus