Panel urges review of mega-dosing
There is no scientific evidence to support the notion that taking
mega-doses of antioxidants such as selenium and vitamins C and E
will protect you against such chronic ailments as cancer and heart
disease, according to a recent federal report. In fact, extremely
high doses of antioxidants may actually cause health problems, says
the report, released April 10 by a 40-member study panel of the
Institute of Medicine (IOM).
Dietary antioxidants protect the body's cells from the naturally
occurring oxygen and nitrogen damage that has been linked to aging
and some chronic diseases. "A direct connection between the
prevention of chronic disease has yet to be adequately established,"
said Norman I. Krinsky, professor of biochemistry at Tufts Medical
School and chairman of the IOM study panel.
However, the report does call for increasing the recommended daily
allowances for vitamins C and E. Women should consume 75 milligrams
and men 90 milligrams of vitamin C--up from the old recommendation
of 60 milligrams for both. For vitamin E, the panel recommended
that men and women get 15 milligrams a day--up from 10 milligrams
for men and 8 for women. Natural sources of the vitamin include
nuts, seeds, liver, leafy green vegetables and some vegetable oils.
The upper limit for E was set at 1,000 milligrams per day. At
high levels, the vitamin acts as an anticoagulant, increasing the
risk of stroke or hemorrhages. The recommended daily intake of selenium
is 55 micrograms. The panel's report set the upper intake level
for selenium at 400 micrograms daily. More than that can cause selenosis,
a toxic reaction marked by hair loss and nail sloughing.