Newswise — Vitamin E won't help; neither will vitamin C.
But one supplement that has proved to help extreme athletes recover from high-intensity exercise surprises even the researchers.
"Sugar water," says David Nieman, of carbohydrate sports drinks that are about 6 to 8 percent sugar.
Nieman is a professor in Appalachian State University's Department of Health, Leisure and Exercise Science. He has studied the effects of sports drinks on athletes' immune systems for the past 10 years.
"We have looked at it from every angle and indeed if there is a magic bullet, it's simply to drink about a liter of a sports drink for every hour of heavy exertion," he says.
Sports drinks, such as Gatorade, 10-K and Quick Kick, only provide a beneficial effect when athletes undergo extreme exercise for 90 minutes or longer.
A marathon runner himself, Nieman knows that extreme exertion weakens the body's immune system, making athletes more susceptible to illness in the days following the exercise.
"When you exercise beyond 90 minutes, carbohydrate stores in your body are low," Nieman said. "The brain senses those low levels and releases stress hormones in huge quantities."
Keeping the body fueled with carbohydrates during long bouts of exercise really is the key to protecting athletes' immune system, he says.
Nieman and other Appalachian faculty crossed vitamin C off the list after looking at the effects of giving large doses of vitamin C to marathon runners. In three separate studies, runners took 1,000 to 1,500 mg of the vitamin a day for a week before competing in a race. "All three studies showed vitamin C compared to a placebo had no effect on reducing the negative immune system changes and oxidative stress occurring in the athletes," Nieman said. "Whether a marathon runner or ultra marathon runner had vitamin C or not, their immune system showed the same stereotypical downturn afterwards."
Next came vitamin E. Researchers at Appalachian thought that because it's fat-soluble, vitamin E might offer more protection to vital cell membranes.
Athletes preparing to compete in a triathlon in Hawaii were given 800 international units (IU) of vitamin E a day for two months before the competition.
"We thought it would reduce oxidative stress and counter the negative immune changes," Nieman said. "It actually did the opposite. It created more oxidative stress."
In fact, the negative changes to the athletes' immune system were off the chart, Nieman said. "The cytokine levels that operate as messenger molecules to the immune system were sky high, showing that the athletes who took the vitamin E had much more immune dysfunction and inflammatory stress compared to athletes who took a placebo," Nieman said.
Nieman says huge supplemental doses of vitamin E should be avoided. "There is growing evidence that too much vitamin E is harmful in many ways and people should avoid huge doses " athletes and non athletes alike," he said. "There is research that suggests that if anything it increases health problems in the general population and for an athlete, instead of countering the physiologic immune stress they go through, it actually makes it worse."
Nieman says the average person only needs about 30-35 IU of vitamin E a day to be healthy. "It's what we have been telling people for a long time: too much of a good thing can hurt you," he said.
While products such as Echinacea and amino acid and fatty acid supplements are being promoted as ways to boost the immune system, Nieman says there is no evidence the substances work within the athletic population.
"I don't think anything, at least right now, can compare to carbohydrate sports drinks, and I don't think that there will be any supplement that will have any meaningful impact," Nieman said.
"We have shown in years of research that mega doses of vitamin C, and now vitamin E, do not help the athlete," Nieman said. "I would encourage them to eat a variety of fruits and vegetables according to the food guide pyramid and concentrate on their training and not think that there is magic in these supplements, because there isn't."