Even though our goal for high-intensity training is to build muscle, inevitably this training will lead to some breakdown during exercise. The anabolic responses to exercise and protein intake during the recovery period lead to enhanced muscle growth after the training session. Some of the amino acids released from muscle during exercise are consumed by muscle for energy production. Ammonia levels, which represent the released of nitrogen from muscle, rise after high-intensity exercise. Along with lactic acid, elevated ammonia levels are believed to contribute to exercise fatigue and perceived exertion.
Alpha-keto acids are analogs to amino acids that do not contain the “amino” component and thus do not produce ammonia. In fact, these acids are able to recycle ammonia and reform amino acids. For example, alpha-ketoglutarate (AKG) can bind free ammonia and form the amino acid glutamate. [you may recall arginine-AKG. This is minus the arginine.] (If you’re interested in supplements containing AAKG, you may wish to check out Cellucor C4 Extreme.) Similarly, branched-chain keto acid (BCKA) can bind ammonia and form BCAAs. It has thus been suggested that supplementation with alpha-keto acids may decrease ammonia levels during high-intensity exercise and thus improve performance.
Researchers in China and Germany recently submitted a randomized, double blinded, placebo-controlled study examining the effects of alpha-keto acid supplementation on high-intensity exercise tolerance and recovery. The study demonstrated that alpha-keto acid supplementation, including AKG and BCKAs at 0.2 grams per kilogram of bodyweight twice per day, produced significant improvements in exercise performance at three and four weeks of taking the supplements. First, the study noted that at 3 weeks into the run/sprint training protocol, the control group receiving the placebo mix (“sugar pill”) had a lower training volume and seemed to fatigue earlier than the alpha-keto acid supplemented group, throughout the rest of the study. Second, the isometric maximum torque and isokinetic muscle performance was significantly improved by the alpha-keto acid supplementation after recovering from the training protocol. Third, the study found a relative improvement in recovery from exercise that may contribute to improved performance.
In conclusion, the scientific basis behind the recommendation for alpha-keto acid supplementation seems to make sense. Randomized, double-blinded, placebo-controlled studies are of the highest quality to determine if a supplement works. This study was well performed, but does have limitations that are a bit too complex to review here. They include a bizarre exercise protocol with a three-minute “all-out sprint” (three-minute sprint is obviously too long), sodium bicarb in the placebo and lack of dietary controls, etc. That being said, it is difficult to apply the results of this study to well-trained bodybuilders lifting weights – since this study included running and untrained athletes trying to perform an overreaching protocol. Hopefully, this study will bring more attention to the alpha-keto acids and more studies will be done on weight-training athletes.