Thought readers would be interested in the latest from the NAS regarding
provitamin A in plant foods.  It seems that we have been misled for 11
years, that provitamin A in produce can yield only HALF as much vitamin A as
previously thought.  Animal sources of true vitamin A are superior.

I take this as an illustration of how important it is to take
"authoritative" information with a grain of salt.

For the full report, including the NAS new guidelines on minerals, go to
www.nas.edu, and click on the Press Release under the front page blurb on
this topic.  Here is an excerpt:

_________________________
Fruits and Vegetables Yield Less Vitamin A Than Previously Thought;
Upper Limit Set for Daily Intake of Vitamin A and Nine Other Nutrients

WASHINGTON -- Darkly colored, carotene-rich fruits and vegetables -- such as
carrots, sweet potatoes, and broccoli -- provide the body with half as much
vitamin A as previously thought, says the latest report on Dietary Reference
Intakes (DRIs) from the National Academies' Institute of Medicine. This
means people need to make sure they eat enough of these fruits and
vegetables to meet their daily requirement for vitamin A, especially if they
do not eat animal-derived foods, which serve as abundant sources of the
nutrient for most people.

"Darkly colored fruits and vegetables are still good sources of vitamin A,"
said Robert Russell, professor of medicine and nutrition, Tufts University
School of Medicine, Boston, and chair of the panel that wrote the report.
"But new evidence shows that it takes twice as much of them to yield the
same amount of vitamin A in the body as we previously understood. People
need to take this into consideration and make sure they select enough
carotene-rich fruits and vegetables to meet their daily vitamin A
requirement. This is especially true for those who don't eat meats, fish,
eggs, or vitamin A-fortified milk or cereal. They may need to significantly
increase their consumption of such fruits and vegetables."

Three carotenoids -- alpha-carotene, beta-carotene, and beta-cryptoxanthin
-- are present in certain orange, red, green, and dark-yellow fruits and
vegetables. They are referred to as provitamin A carotenoids because they
can be converted in the body to retinol, an active form of vitamin A. Based
on a comprehensive review of recent research, the panel found that the
amount of provitamin A carotenoids required to create a unit of retinol is
twofold higher than the amount believed needed in 1989, when the National
Academy of Sciences last issued recommendations for vitamin A.

____________________________________

Don Matesz