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Last week there were two absolutely contradicting reports on vitamin
E. I will report on each separately and summarize my thoughts in
the comment section at the end.
A JAMA study showed that supplementing the diets of healthy people
with vitamin E had no effect on the rate of "oxidative damage"
in their bodies.
Oxidative damage is caused by the activity of "free
radicals'' -- compounds released during normal cell processes.
Experts have linked oxidative stress to a number of major illnesses,
including cancer and heart disease.
Antioxidants such as vitamins C and E
are thought to reduce levels of free radical activity.
The investigators saw an increase in circulating vitamin E levels
after 8 weeks in people taking the supplements compared with those
taking the placebo. However, the level of oxidative damage, measured
via chemicals released in the urine, remained
nearly unchanged regardless of the varying doses of vitamin E taken.
The study is one of the first to look at the effect of vitamin
E on oxidation in the body. Previous studies relied more on test
tube-like measurements. This study is good because it measures oxidative
damage actually occurring within the living body.
The information provided in this study along with the results of
other lager studies add up and say to me that vitamin
E does not result in favorable outcomes for reducing
death rates, or rates of heart disease or stroke. Vitamin E is not
really protecting against oxidative harm to fats as many researchers
had thought it would.
Journal of the American Medical
Association March 7, 2001;285:1178
High-Dose
Vitamin E May Protect Arteries
Another report showed that taking high
doses of vitamin E may help prevent heart attacks and
strokes by preventing the progression of hardening of the arteries.
Researchers said the effect is limited to doses of more than 300
milligrams a day. These high doses -- sometimes as high as 1,000
milligrams a day -- were associated with a slower progression of
atherosclerosis, the disease commonly called hardening of the arteries.
Researchers measured the effect of vitamin E by measuring the build-up
of plaque in the carotid arteries of 573 men and women who work
for a California utility company. At annual check-ups ultrasound
was used to measure the thickness of the arterial walls in the volunteers
who were healthy and free of diagnosed cardiovascular disease when
the study began in 1994.
The study volunteers were divided into four groups based on the
use of vitamin E. The benefit was only seen in the group taking
the highest level of the vitamin.
The benefit was limited to vitamin E from
supplements, no effect for dietary vitamin E was found.
While vitamin E was beneficial, vitamin
C -- another antioxidant -- had no benefit and appeared
to promote the progression of disease.
American Heart Association's
41st Annual Conference on Cardiovascular Disease Epidemiology and
Prevention San Antonio, TX March 8, 2001
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