>Iceberg salad is astonishingly high in vitamin A.
OKAY, ONCE AND FOR ALL! Let's clear up the *Carotene and Vitamin A
Confusion*
Many people mistakenly believe that beta-carotene is the same as vitamin A.
They have also been led to believe that sunlight can provide all the
necessary vitamin D. However, the beta carotene found in vegetables is not
the same as vitamin A. The popular press has added to the confusion: few
writers and health *experts* nowadays know that beta carotene is not the
same as vitamin A and few editors know enough to catch the error, so it goes
unnoticed and uncorrected.
Under the best conditions, humans can absorb only a fraction of the beta
carotene (pro-vitamin A) from vegetables. Average beta carotene absorption
for vegetables ranges from 16 to 35%. Only about 1% of the carotene from
raw carrots has been found to be absorbed into the blood and 5% to 19% of
the carotenes from cooked carrots. Only when a vegetable is sliced thinly,
grated, chopped, cooked, pureed or chewed very well are the cell walls of
the plant broken down sufficiently to allow the carotenes to pass into the
blood.
The reason? The carotenes in vegetables are locked inside the plantıs cell
walls, made of cellulose, which is indigestible by humans. Furthermore,
very low fat meals and a low-fat diet can hinder absorption of beta-carotene
and its conversion to vitamin A. Fat stimulates the flow of bile, with
which beta carotene must combine to enter the blood. So, you need to eat
vegetables with some friendly fats to improve the conversion of
beta-carotene into vitamin A (a fat-soluble nutrient). Similarly, a low
vitamin E intake (common in America) can hinder the conversion of beta-
carotene into vitamin A.
Eating foods already rich in (true) vitamin A is essential for optimal
health and reproduction. Children have an even more limited ability to turn
beta-carotene into vitamin A, particularly in the absence of animal fats.
Diabetics, individuals with low thyroid function, impaired liver function,
poor digestion, or those who adhere to very low-fat or vegan diets, or diets
high in polyunsaturated oils or nitrites (preservatives) and nitrates (from
non-purified drinking water contaminated by certain agricultural chemicals)
are even more prone to deficiencies due to difficulty making this
conversion.
Eat lettuce till the cows come home but you cannot get any Vitamin A. Try
cod liver oil, liver, other organ meats, etc. We need to eat animal source
food to get our essential As!
Sorry, big pet peeve. (Been vitamin A deficient in the past!)
Rachel
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