April 30, 2004

Antioxidant vitamins may protect runners

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Jason Morrow, M.D., is the author of a study indicating that marathon runners might experience less muscle damage if they take antioxidant vitamins. Photo by Dana Johnson

Antioxidant vitamins may protect runners

A new study suggests that marathon runners might experience less muscle damage if they start a regimen of antioxidant vitamins prior to entering their next race.

Jason Morrow, M.D., professor of Medicine and Pharmacology, and collaborators at Oregon State University investigated the effects of running an ultramarathon (a 32-mile marathon) on oxidant injury and inflammation and whether antioxidant vitamins could prevent this damage.

Oxidant injury happens when highly reactive molecules called free radicals attack cellular proteins, DNA or lipids. Free radicals, which are by-products of normal metabolism, are produced in excess in certain disease states, after exposure to toxic substances and after strenuous exercise.

“I think overall there is a great interest in the medical community and the lay community as to the role of oxidant stress in human disease and human activity,” Morrow said. “It’s linked to virtually every disease and everything that people do.”

And, yes, that includes healthy activities like exercise, particularly strenuous exercise.

“We have the ability to quantify oxidant stress in humans. We have characterized a group of molecules made in the body called isoprostanes, which are derived from a fatty acid called arachidonic acid,” Morrow said.

“These molecules provide a highly accurate index of this oxidant stress in humans and currently are the gold standard to assess oxidant stress.”

The lab test that Morrow has developed, in addition to being accurate, is less invasive than other oxidant stress measures, making it readily usable in a human population.

Morrow’s lab has shown in previous studies that isoprostanes are increased by strenuous exercise, like marathons.

“If you can show that oxidant stress is increased, it is presumed to be bad. Then the next logical question is — can you prevent it?” Morrow said.

To answer this question, the researchers recruited physically fit, noncompetitive athletes (11 men and 11 women) to participate in the study. The athletes were given a combination of vitamins E and C at doses similar to those in commercially available supplements.

Their diets were also under strict control, and their amount of exercise during the study was closely monitored to ensure that any effects the researchers found could only be attributed to the vitamin regimen. After six weeks of this treatment, the runners completed an ultramarathon.

Morrow measured levels of isoprostanes and markers of inflammation in the runners’ blood after they completed the marathon.

The results, reported in March 30 online edition of the journal Free Radical Biology and Medicine, showed that the runners treated with the vitamin combo had lower levels of isoprostanes after the race than runners taking a placebo. This indicated that the vitamin treatment prevented the oxidant injury caused by the marathon.

However, the vitamins had no effect on measures of inflammation, suggesting that the two processes — oxidant stress and inflammation — are operating independently.

So what does this mean for marathoners?

“Should (a marathoner) take antioxidant supplements? I think the jury would still be out on supplementation over and above a healthy lifestyle. Would it hurt (them) to do it? I have no evidence to say it would hurt, and it could be beneficial,” Morrow said.

“From a marathon point of view, the administration of these agents takes at least a few weeks to reach steady state, so starting supplementation (the night before) is unlikely to have this effect. If you’re going to do it, it should be done some time prior to the race rather than at race time,” Morrow said.

However, Morrow cautions runners against seeing these results as a magic bullet.

“This does not negate the things that are likely even more important to marathon runners, like proper training, proper hydration, and healthy diet and lifestyle.”

Morrow, a marathoner and daily runner himself, has a number of ongoing studies looking at the role of oxidant stress in strenuous exercise events like the Hawaiian Ironman Triathlon and the Western States Endurance Run, and in the training of Olympic Athletes.

Another area of interest for Morrow is in the development of more potent antioxidants that might have more beneficial effects than vitamins E and C.

“While vitamins E and C have antioxidant properties, they are not profoundly potent. So there is a need for more potent antioxidants,” Morrow said.

To that end, he collaborates with Ned Porter, Ph.D., chair of the department of Chemistry to explore the utility of a novel group of antioxidants, developed by Porter, in decreasing oxidant stress in animals and humans. These compounds, called 3-pyridinols and 5-pyrimidinols, are vitamin E-like substances about a hundred times more potent than vitamin E.

Morrow credits the division of Clinical Pharmacology with providing him the opportunity to be involved in important translational research such as this.

“There is no other division like it at Vanderbilt, or really even in the rest of the country. To be able to apply rigorous basic science to answering questions about human pathophysiology has been invaluable,” Morrow said.

The research was supported by grants from the National Institutes of Health, the Burroughs Wellcome Fund, and the Natural Source Vitamin E Association.