SAN DIEGO — Female athletes older than 35 years get a performance boost from beta-alanine supplements, a new study shows.
"We did see an improvement in time-trial performance," said Jordan Glenn, MS, PhD candidate, from the University of Arkansas in Fayetteville.
Beta-alanine, a nonessential amino acid, appears to function as a precursor to carnosine in muscle tissue. Carnosine buffers hydrogen ions, making muscle tissue less acidic and delaying fatigue.
Beta-alanine has been shown to have a beneficial effect on exercise in some studies, but not in others. Glenn and his colleagues decided to assess the effect of supplementation on highly trained women.
They chose this population because women have less than one-third the baseline carnosine in their muscles as men, but require less beta-alanine supplementation to increase intramuscular carnosine, Glenn explained.
In addition, carnosine loading with beta-alanine supplementation is more pronounced in trained than in untrained muscles, he added, and carnosine levels decrease with age.
"It creates a perfect storm, in which female masters athletes may be able to see more of an effect," he said.
Glenn presented the finding here at the American College of Sports Medicine 62nd Annual Meeting.
In their study, Glenn and his colleagues randomly assigned 11 female masters cyclists to beta-alanine 800 mg and 11 to placebo four times a day for 28 days.
The two groups were statistically matched for weight, height, body fat, and aerobic capacity.
There was no significant difference between the beta-alanine and placebo groups in average age (54 vs 53 years), length of cycling history (5.38 vs 4.27 years), or weekly cycling distance (131 vs 92 km).
The researchers assessed peak oxygen consumption as each cyclist rode a cycle ergometer.
Twenty-four hours later, they measured time to exhaustion when each athlete was cycling at 120% of the previous day's peak oxygen consumption. They then calculated total work completed by multiplying time to exhaustion by power output.
To assess serum lactate — a measure of pH balance — fingertip blood samples were collected immediately after the cycling and after about 20 minutes of recovery.
The grip strength of the athletes was also measured.
At baseline and during the first three weeks of the study, these measurements were not significantly different between the two groups.
However, by the end of the fourth week, changes in endurance became significantly greater in the beta-alanine than in the placebo group, although hand-grip strength did not change significantly in either group.
Table: Changes in Endurance During the 28-Day Study Period
|Variable||Beta-Alanine Group, %||Placebo Group, %||P Value|
|Time to exhaustion||23||1||<.05|
|Total work completed||21||2||<.05|
This is the first study to measure changes at intermittent weeks, Glenn reported.
The fact that it took 4 weeks for beta-alanine supplementation to have a significant effect gives us an idea of the minimal time required, he added.
After the presentation, one member of the audience asked if the researchers had measured carnosine levels.
Glenn explained that his laboratory did not have that capacity to do that. However, he said, "there are a lot of really good data that indicate that 3.2 g of beta-alanine is enough to significantly increase carnosine to levels that increase muscle performance in other populations. So we do believe that's what is causing these improvements."
He noted that it would be interesting to compare carnosine levels in this population and in age-matched trained males or trained younger populations.
"Would you advocate the use of beta-alanine in this population of people?" asked session moderator Andrew Jones, PhD, from the University of Exeter in the United Kingdom.
"Absolutely," Glenn responded. "Not for the general population, but for an athletic population."
But it might be too soon to make that recommendation, Catherine Jackson, PhD, from Fresno State University in California, said in an email to Medscape Medical News.
"This research fits in with previous studies done with beta-alanine," she said, but it is not clear what dosage should be used.
"One of the side effects of higher doses is paresthesia, for which there is no good explanation," she explained.
The researchers deliberately spread the beta-alanine into small doses taken four times per day to avoid causing paresthesia, Glenn reported.
Mr Glenn and Dr Jackson have disclosed no relevant financial relationships.
American College of Sports Medicine (ACSM) 62nd Annual Meeting: Abstract 2200. Presented May 29, 2015.
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Cite this: Beta-Alanine Boosts Performance in Female Masters Athletes - Medscape - Jun 16, 2015.