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 zinc.
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 study's conclusions.
"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.