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NEW YORK (Reuters Health) - Older people taking a sports nutrition supplement favored by Olympic athletes show substantial increases in their ability to withstand fatigue, new research shows.
"We were surprised that it had this kind of impact," Dr. Jeffrey R. Stout of the University of Oklahoma in Norman, who led the study, told Reuters Health. "We weren't sure that this would impact their physical capacity like it did."
Stout and his colleagues found that men and women given a low dose of beta-alanine for 90 days were able to exercise nearly 30 percent more intensely before becoming fatigued.
Beta-alanine increases the amount of carnosine in the muscles, which is key to helping sustain a neutral pH in muscle tissue. When people exercise to fatigue, the muscles become more and more acidic (lactic acid buildup is a byproduct of this process, but not entirely responsible for it), and carnosine is believed to help buffer against this acidity, allowing people to do more without "feeling the burn."
Older people tend to have less carnosine in their muscles, Stout explained, largely because they don't eat as much meat as younger people.
Taking carnosine supplements is useless, Stout said, because the body breaks the protein down immediately. But taking beta alanine, an amino acid that is a component of carnosine, triggers the production of carnosine in muscle tissue, he added.
Stout and his team had previously demonstrated that beta alanine helped young people increase their exercise capacity by 12 percent to 15 percent. In the current study, they recruited 26 men and women, average age about 73, to take 800 mg of beta alanine three times a day or a placebo.
The maker of the supplement, Natural Alternatives International in San Marcos, California, supplied the supplements and placebo but didn't help pay for the study, according to Stout.
Study participants had their exercise capacity tested on a special exercise bike called an ergometer, and the researchers used electrodes to measure electrical activity in their thigh muscle, which signals acid build-up.
The individuals on placebo showed no increase in their ability to withstand fatigue, but those on beta alanine were able to exercise 28.6 percent more intensely, Stout and his colleagues found. The improvement in exercise capacity was similar to that seen in a previous study in which older people underwent 12 weeks of endurance training.
Study participants didn't experience any ill effects while taking the supplement, and the dose was lower than the 6.4 grams daily that Stout and his team gave younger adults, the researcher noted.
Stout says he recommends the supplement to everyone he knows who's over 60. "I know I have my own parents on it," he said.
"It can't hurt and it can only help, but elderly folks must be patient," the researcher added. "It takes a while for the carnosine to increase in the muscle. They probably won't see any benefit for about 4 weeks."
Nevertheless, he added, the patients in his study who were taking the supplement did notice a difference in their ability to go about their daily activities, before they or the researchers were aware that they were in the placebo or supplement group.
"Some of the subjects said I don't care what it is, I want more of it."
SOURCE: Journal of the International Society of Sports Nutrition, November 7, 2008.