Asking about alpha-keto acids

Alpha-keto acids are related to amino acids, which are the building blocks of protein. To study how alpha-keto acids affect tolerance to hard physical activity, researchers invited 33, untrained young adult males to begin a four-week exercise program. The program consisted of five sessions per week of 30 minutes of running at a moderately hard pace, followed by three, three-minute sprints at the end of each session. The men were randomly selected to take one of the following:

• 0.2 grams of alpha-keto glutarate per kilogram of body weight per day
• 0.2 grams of branched-chain keto acids per kilogram of body weight per day (branched-chain keto acids can be converted to branched chain amino acids)
• A daily placebo that provided the same calories as the keto acid supplements, but with no keto acids in it

During the four-week exercise program, the men completed questionnaires to assess stress and emotional exhaustion, and the researchers measured maximum power output during exercise each week.

After four weeks, compared to men in the placebo group:

• men in the alpha-keto glutarate group had significantly greater power output,
• men in the branched-chain keto acid group had significantly greater power output; their output was somewhat lower than in the alpha-keto glutarate group, though this difference was not significant, and
• men in both the alpha-keto and branched chain keto acid groups had significantly lower stress and emotional exhaustion.

Easing into exercise

This small study suggests keto acid supplements may help young men who have not been exercising regularly to tolerate hard physical activity better, with less stress and exhaustion. Consider the following before deciding whether you can benefit from keto acids:

• Be safety savvy. The study lasted four weeks. It does not tell us if taking keto acid supplements long-term is safe or effective. One other small study in men suggests these supplements are safe and well-tolerated when taken for a few days to a few weeks. Beyond this, we don’t know.
• Consider gender and age. The study included young men. It does not tell us whether keto acids will improve exercise tolerance in older men, or young or old women.
• Assess goals. The study looked at untrained men who were then put through an intense exercise program. If you already exercise regularly, you may gain no additional benefit by taking these supplements. If your physical activity plan includes mostly moderate exercise, such as brisk walking, you are unlikely to benefit from these supplements.
• Start slow. To establish good physical fitness, begin slowly, and work your way up to longer and/or more intense exercise sessions. Don’t forget that all activity counts. Taking the stairs, walking to the store, riding bikes with your kids, or shooting some hoops are all good options for helping you reach 30 minutes of activity per day.

(J Int Soc Sports Nutr 2012;9:37)