While veteran runners and ambitious joggers toil through the winter months as they prepare for the spring marathon season,two recent studies suggest that certain nutrients –vitamin E and protein,namely – can bolster the body's health during times of demanding exercise.
Researchers in Oregon examined the benefits of vitamin E supplements for runners in a 50-kilometer (31 mile) ultramarathon in Corvallis. Their study found that runners taking vitamin E did not experience the usual increase in lipid oxidation – a kind of damage that can weaken cells and cause long-term cardiovascular problems – that results from extreme exercise.
“We looked at a marker of oxidative damage,” said Dr. Maret Traber,principal investigator at the Linus Pauling Institute at Oregon State University. Traber helped conduct the study,published in May in Free Radical Biology & Medicine,a medical journal.
“It's called isoprostane,and isoprostanes are important because they're associated with an increased risk of heart disease. So we were really interested. Could we protect the runners?” she asked.
The answer was yes.
Traber said a daily dose of 400 international units of vitamin E protects endurance athletes from damage that is linked to a number of long-range health problems,including diabetes,stroke,heart disease and Alzheimer's. She stressed,however,that a vitamin E supplement is necessary because the amount found in a regular diet isn't enough.
(A study published Jan. 4 in the Annals of Internal Medicine suggested that high doses of vitamin E may slightly raise overall mortality. The study examined 19 clinical trials involving more than 130,000 participants,but some critics said they were not persuaded because of the difficulty in combining results from several studies.)
Meanwhile,another study shows that protein consumption after exercise can help to maintain the body's short-term health during intense training periods.
Researchers at Iowa State University studied Marines during their 54-day basic training. A third of the recruits received a protein supplement after workout sessions,while the rest received a carbohydrate supplement or a placebo. The protein group experienced fewer infections,fewer treatments for muscle soreness and far less heat exhaustion than the others.
While protein has been known to help rebuild muscles after physical stress,the results of the study extend beyond that,said Paul Flakoll,a professor of nutrition at Iowa State who published the study in the Journal of Applied Physiology in March.
“People training at that level – marathoners are a good example – a lot of times have compromised immune function,” he said. “There's been a lot of work with antioxidants in marathon runners,but it looks like protein may be very important for that as well.”
Flakoll emphasized protein should be consumed immediately after exercise,but he said that an appropriate amount can be found in protein milkshakes or bars or in protein-rich food. A pill isn't necessary.
That approach may please marathoner Deena Kastor,31. The 2004 Olympic bronze-medalist said nutrition is essential to her success,but she doesn't get wrapped up in the multitude of “gimmick” supplements or diets that continually appear on the market.
“I believe that you can get all the nutrition you need through food that you eat,so I don't believe in supplementation at all,” Kastor said. “I definitely try to get a combination of proteins and carbohydrates within a half hour of running,but I'd rather get it though eating some leftover steak from the night before and throwing it into some pasta.”
Food or pills,or both,is an athlete's decision,but any runner preparing for a marathon should monitor nutrition as meticulously as training,Traber said.
“There's a lot of enthusiasm for extreme exercise. Yes,do the extreme exercise,but protect yourself.”