vitamin A toxicity

[Guest guest]

In a message dated 9/25/02 3:24:59 AM,

writes:

>it occurred to me only after she left that the research on vit. A toxicity

>

>may have been done with *synthetic* vit. A. clearly, WAP's groups were

>not

>

>dropping from vit. A toxicity, so there was something about their

>

>nutrition/lifestyles that prevented any problems with vit. A toxicity.

>also,

>

>i mentioned to her that current research on vit. A toxicity is conflicting.

>

>one large-scale study gave 300,000 IU daily to a large group of people

>for 2

>

>years and no toxicity symptoms were noted! i do think it's an interesting

>

>question that she raised though - is it possible to get vit. A toxicity

>from

>

>eating large amounts of saturated fat?

Modern Nutrition in Health and Disease (2002) says that although vitamin A

toxicity from too much liver has been reported ( chronic (years)

over-consumption of liver or eating of something exotic like polar bear

liver) , most vitamin A toxicity is associated with prolonged consumption of

very high potency single nutrient supplements of pre-formed vitamin A

(retinol -- not beta-carotene). Symtoms include headache, bone/joint pain,

elevated liver enzymes, liver disease. Krause's Food, Nutrition and Diet

Therapy (2000) says that " persistent large does of vitamin A (over 1000 times

the required amount " ... -- required for adult woman is 800 retinol

equivalents (RE), for men, 1000 RE -- ... " which overcome the capacity of

theliver to store the vitamin, can produce intoxication. This is marked by

high plasma levels of retinyl ester associated with lipoproteins.

Hypervitaminosis in humans in characterized by changes in the skin and

mucous membranes. Dry lips (cheilitis) is a common early sign, followed by

dryness of the nasal mucosa and eyes; later signs include dryness, erythema,

scaling and peeling of the skin, hair loss, and nail fragility. Headache,

nausea and vomiting have also been reported. (Weight loss is not uncommon)

Very high intakes {exceeding 66,000 IU/day--(1000 IU = 300 RE)} can cause

liver disease. " Too much vitamin A can be measured -- serum vitamin A of 250

-6600 IU/ml. Most vulnerable to over dose of pre-formed vitamin A is unborn

fetus -- would need daily exposure of more than 20,000 - 25, 000 IUs. .

Accutane -- an acne medication is basically retinol -- huge does of

pre-formed vitamin A -- a girl on this stuff has to have monthly pregancy

test to make sure she's not pregnant because the it could harm the fetus. It

works by making the facial skin peel.

Remember that beta-carotene, the pro-vitamin found in plants food is

completely non-toxic -- most you can get from too much is yellowing of the

skin.

In light of the above, I can't imagine someone eating a la Nourishing

Traditions or even high protein/high fat diets incurring a problem with toxic

levels of vitamin A unless they eat something like beef liver daily for a

long time or take large quantities of retinol supplements for a long time.

Sometimes Inuits and other artic people who eat polar bear liver have some t

oxicity symptoms such as peeling skin; there have been one or two reported

deaths (young girl who ate a whole polar bear liver was supposed to have

died). I think some of the mainstream writers (who freak at the idea of

people eating meat and fat) use issues like vitamin A toxicity to scare

people.

Oddly enough in an exchange with Sally once wherein I complained of some

menopause symptoms, she advised that I take in much more vitamin A!!

Namaste, Liz

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