Beta-alanine helps seniors stave off fatigue

By Anne Harding

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.