>> >Since rice is a staple eaten in large quantities in Asian societies,
>> >vitamin A rice could lead to excessive intake of vitamin A especially
among
>> >those who do not suffer from vitamin A deficiency. Excess vitamin A can
>> >lead to hypervitaminosis A or vitamin A toxicity.
>>
>> This statement is as wrong as it can get. Beta-carotene is *not*
>> vitamin A, and can not cause hypervitaminosis A.
>
>I do not know anything about this - perhaps others can comment further on the
>connection, if any, between beta carotene and Vit A. Ann.
Below is from another list which addresses this question. Mike Miller
"Hi All,
This is actually an interesting biochemical phenomenon--that
Vitamin A, or
retinol, is a series of chemical bonds between carbon atoms attached to a
carbon ring, all of which can absorb a lot of energy from overly reactive
chemicals, like free radicals. It also fits a number of huge enzyme
molecules that allow its use in metabolism. Beta-carotene is essentially
two molecules of retinol attached to each other at the ends farthest away
from the rings. The body can store beta-carotene in the skin, as well as
the liver and other places, sometimes making vegans, vegetarians and others
consuming lots and lots of beta-carotene have carrot-colored skin, usually
especially the palms and soles. That is not dangerous, and gives them a way
to recognize each other in a crowd...;-) ( I just threw that in there...)
Retinol can be toxic, especially to nerves, if too much is
consumed, so we
should not get more than about 25,000 to 50,000 units a day, if a normal
sized adult. The body will split beta-carotene into retinol as it needs it,
and won't split too much and become toxic, explaining how retinol can be
toxic, and beta-carotene isn't.
Enjoy those colorful fruits and veggies, and wear your carrot
colored skin
proudly, just be careful with retinol. If the label says "Vitamin A," it's
usually referring to retinol, since it's available, cheap, from animal
sources.
Best of fortune.
Roger
-----------------------------------------------------------------------
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Roger Littge email: rolittge@ucdavis.edu"
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