Antioxidants Offer Benefits for Those Participating in Strenuous, Moderate-Altitude Training
Dec. 16, 1999 (New York) -- Antioxidants have been shown to help the body
cope with excess oxidative stress, a condition where the body essentially has
too many free radicals, the waste products that result from all the chemical
reactions occurring in the body. Such stress is often driven by environmental
insults, such as smog, high altitude, radiation, and sunlight, and is related
to heart disease, stroke, and some cancers. A new study suggests that
antioxidants may be of value, particularly for healthy individuals
participating in strenuous, cold-weather activities at moderate elevations. The
study, however, is drawing criticism from antioxidant researchers.
The study, reported in the November issue of Journal of Nutrition,
suggests that the benefits of antioxidants in protecting the body in such
situations are not necessarily that strong. In fact, the research team only
found an association between a mixed supplement containing vitamins E and C,
selenium, and zinc and blood pressure lowering. High blood pressure is an
indicator of oxidative stress. No other markers of oxidative stress responded
to antioxidant supplementation, according to the researchers.
In the study, investigators from the University of Utah in Salt Lake City,
the U.S. Naval Health Research Center in San Diego, and Abbott Laboratories in
Columbus, Ohio, evaluated several markers of increased oxidative stress from
strenuous training at moderate altitudes. Patients in the study consisted of
healthy Marines undergoing strenuous training routines and fed a military diet.
They sorted the Marines into four groups: a placebo group, a vitamin E
supplement group, a vitamin C supplement group, and a mixed supplement group.
The mixed supplement contained vitamins E and C as well as selenium and
Experts tell WebMD, however, that even though they believe research on
supplements should be subjected to the very same standards that drugs are
(supplements are not regulated by the FDA), they do not have confidence in the
"Too much [oxidative stress] can clearly be damaging," Chris
Pritsos, PhD, tells WebMD. Numerous studies have pointed out that "people
training at moderate elevations have higher levels of oxidative stress."
And he says the best research on antioxidants shows they can help neutralize
excess free radicals that are produced when the body sustains environmental
insults. Pritsos is a professor and biochemist in the department of nutrition
at the University of Nevada in Reno.
Overall, Pritsos was critical of the study and its design. "I was
disappointed by ... how they [failed to] control for their subjects'
differences" on measures relevant to oxidative stress. Of particular
concern to him was that the researchers did not take possible confounders, such
as prior diets, prior training, and most importantly, smoking into account.
"Smoking has a major impact on oxidative stress, and all of these are