Study Shows Vitamins C And E Can Prevent Metabolic Damaage In Extreme Exercise

The type of metabolic damage observed in these runners is also often found after heart attacks, strokes, surgery and other traumas, the report noted, and the researchers say this study provides more evidence for the value of vitamin E supplementation as an antioxidant that, at the least, can help prevent damaging lipid oxidation and some of the health concerns associated with it.

The study was just published in a professional journal, Free Radical Biology and Medicine.

In the controlled research, the OSU scientists examined 22 runners who performed in a 50-kilometer "ultramarathon," running more than 30 miles up and down hills near Corvallis, Ore. Half of the runners were given daily supplements of 1,000 milligrams vitamin C and 400 international units of vitamin E for six weeks prior to the race, while the other half ate only their normal, healthy diet.

An analysis of "biomarkers" in the control group that received no supplements showed significant increases in lipid peroxidation following the race - these biomarkers were at levels that are often seen after someone has had a heart attack. The runners taking vitamins C and E were comparatively normal. Interestingly, the male runners who did not receive supplements continued their unusually high levels of oxidized lipids for almost a week, while the metabolism of females returned to normal in a day.

"This study clearly showed that supplementation with these antioxidant vitamins could help prevent the significant levels of lipid oxidation that are associated with intense exercise," said Angela Mastaloudis, an LPI researcher and co-author on the study. "And it's worth noting that the people who did not take supplements, but did have a vitamin E intake that would be about the amount suggested by the federal RDA, did not gain those protective benefits."

According to Mastaloudis and Maret Traber, a co-author and professor with the Linus Pauling Institute, the findings of this study may have ramifications far beyond just people who undergo unusual exercise regimens. Oxidative stress and higher levels of lipid oxidation are seen in a wide range of health problems, ranging from diabetes to heart disease, stroke, Alzheimer's disease, smoking and even obesity, the researchers said.

"Studies such as this are done with healthy people on good diets facing an unusual stress due to athletic exertion, but many other people may face similar metabolic stress due to chronic disease," Traber said. "We often can't do dietary studies with people who are very ill, due to ethical concerns, so we used marathon runners to learn more about the effects of stress and ways to prevent damage from it. These athletes in a race can have a 10- to 20-times increase in whole body oxygen consumption."

Traber and Mastaloudis said they wanted to stress that antioxidant vitamins are no substitute for a healthy lifestyle, balanced diet, proper weight and regular exercise.

"However, this study does suggest that people who have high levels of oxidative stress and lipid oxidation due to other chronic health problems might benefit from supplements of vitamin E that are higher than the current RDA for this vitamin," Traber said.

Lipids are fats, the researchers said, which in the body are found in cell membranes. When they are oxidized, however, they can ultimately cause a whole range of health concerns, such as damage to cells, increased blood pressure and blood clotting, plaque formation in artery walls, and blood vessel constriction.

"One of the things we're finding more and more is that different antioxidants have fairly specific jobs that often don't overlap all that much," Traber said. "For instance, some claims have been made that vitamin E can play a role in preventing DNA damage, muscle fatigue, muscle damage or improved performance, and we simply don't find much evidence to support that."

But when it comes to preventing lipid oxidation and the health concerns associated with that, vitamin E may be of profound benefit, the OSU researchers said.

"I think it's pretty safe to say, at this point, that marathon runners should absolutely be taking supplements of vitamin E," Traber said. "A larger question is to determine who else could benefit."

It might be quite a few people, the OSU scientists said. For one thing, various studies have shown that less than 20 percent of the American public gets even the RDA of vitamin E, let alone takes a supplement. And this vitamin is most commonly obtained from fat and oils, which are increasingly being reduced as more people move towards a low-fat diet.

Traber is one of the nation's leading experts on vitamin E, and has served on federal panels studying the recommended levels of this vitamin.

The most recent RDA recommendation, Traber said, is based largely on data that is decades old, and does not really explore the optimal intake for people who have depressed levels of micronutrients for various reasons, such as athletic exertion, heart disease, other degenerative diseases, or simple lack of physical activity.