A - plentiful in foods like yams, carrots, asparagus, and
eggs - has many health benefits as an antioxidant, such as
good vision and healthy skin. However, eating too much vitamin
A has been shown to have negative side effects. Long-term,
regular ingestion of excessive doses of vitamin A may lead
to an increased risk for osteoporosis and hip fracture.
From 1980 to 1998, the authors of a recent study in the Journal
of the American Medical Association examined over 70,000
women between the ages of 34-77. Hip fractures were recorded,
excluding severe trauma cases like car accidents in which
fracture was unavoidable; fractures were compared to the women's
diets regarding vitamin A intake from foods and supplements
over the 18 years.
Women in the group with the highest overall vitamin A intake
from foods and supplements combined were almost 50% more likely
to suffer hip fractures than women with the lowest intake.
Women with the highest intake of retinol (pure vitamin A)
from multivitamins/supplements were approximately 90% more
likely to experience hip fracture. A full 21% of the women
in the study consumed more than the "tolerable upper limit"
of vitamin A, nearly all from supplements.
This study offers further evidence that excessive vitamin
A consumption, particularly from supplements, may cause osteoporosis
in women. The best way to limit your vitamin A intake is to
obtain it only from foods, in its beta-carotene form. Besides
increasing fracture risk, excessive levels of vitamin A can
be toxic and even fatal.
Feskanich D, Singh V, Willett WC, et al. Vitamin A intake
and hip fractures among postmenopausal women. Journal of
the American Medical Association 2002:287(1), pp. 47-54.
To read more about women's health, check out http://www.chiroweb.com/tyh/women.html.