Researchers from University of Ulm in Germany and Southeast University, Nanjing in China explained that a decrease in tolerance to exercise may be related to a build-up of ammonia in the body, called hyperammonemia.
They hypothesized that alpha-keto acids may offer benefits because alpha-keto acids are nitrogen-free sources of amino acids. They are converted in the body by a process called transamination into amino acids, thereby reducing the cellular levels of ammonia.
In order to test this hypothesis, the researchers provided daily supplements of alpha-keto acids to untrained men for five weeks and found that this was associated with improvements in exercise tolerance and training effects.
“Physical exercise is of great significance to public health,” they wrote in the Journal of the International Society of Sports Nutrition.
“This study has shown that nutritional supplementation with alpha-keto acids in healthy, untrained subjects significantly improved exercise tolerance, training effects, and stress-recovery state.
“Therefore, observations to further verify the potential benefits of alpha-keto acid supplements in subjects during active training will be of scientific and clinical value.”
Led by Ulm’s Yuefei Liu, the researchers recruited 33 untrained young male adults and subjected them all to four weeks of training. The participants were also randomly assigned to one of three groups: The first group received alpha-ketoglutarate (0.2 grams per kilogram of body weight per day, Evonik Rexim SAS, France), branched-chain keto acids (0.2 grams per kilogram of body weight per day, Evonik Rexim SAS, France), or an isocaloric placebo. The intervention continued for one week after the end of the training regime.
Results showed that supplementation with alpha-ketoglutarate or the branched-chain keto acids was associated with significant improvements in training volume, maximum power output and muscle torque, compared to the placebo group.
In addition, the placebo group reported higher levels of general stress and emotional exhaustion, compared to the alpha-keto acids groups.
The researchers claimed that this is the first study to investigate the effects of alpha-keto acids supplementation on physical training.
“Although the underlying mechanism of the effects of the supplementation of α-keto acids on physical exercise remains unclear, we have shown the beneficial impact of the supplementation with alpha-keto acids on physical training in untrained individuals.
“Further studies are needed to clarify whether alpha-keto acids supplementation affects amino acid homeostasis and ammonia metabolism during and after physical exercise,” they concluded.
Source: Journal of the International Society of Sports Nutrition
2012, 9:37, doi: 10.1186/1550-2783-9-37
“Improved training tolerance by supplementation with alpha-Keto acids in untrained young adults: a randomized, double blind, placebo-controlled trial”
Authors: Liu Y, Lange R, Langanky J, Hamma T, Yang B and Steinacker JM