Suffering through that second protein shake may be a waste of time and money for many athletes-in-training. After several studies, there is no conclusive evidence that increased protein intake enhances the training experience or its results. According to a recent report, however, some amino acids present in dietary protein may enhance physical performance for physically active people.

Some of these 20 or so amino acids present in dietary protein have been found to have little impact on physical performance. For example, tryptophan, which has been used to enhance pain tolerance, possesses little, if any, real benefit. Also, the use of Branched chain amino acids (BCAA) for increased endurance is a matter that needs further study, after studies have been inconclusive regarding such benefits.

Taurine, when ingested independently, has been demonstrated to improve desired functioning. In the metabolic process, such as heart contraction and antioxidant activity, taurine is a key ingredient in energy drinks like Red Bull. When consumed as part of an energy drink, taurine has been shown to improve cardiac functioning, during post-exercise recovery. Taurine supplementation has been shown to increase VO2 max and lengthen time to exhaustion, which is likely attributable to its antioxidant and cellular protection qualities.

Glutamine, which is fuel for certain cells comprising the immune system, has been theorized strengthen such cells as they become weakened due to prolonged exercise. In short, glutamine may reduce an athletes susceptibility to illness after prolonged training.

Potassium and magnesium aspartates, which are salts of aspartic acid, have also been utilized for their likely ergogenic capacity. As they are believed to enhance fatty acid metabolism and mitigate the accumulation of ammonia during training, many athletes supplement with aspartates. Aspartates are thought to enhance performance and endurance. Of the aspartate studies, approximately 50% support the prevailing belief.

Of the most benefit to an athletes exercise training is the consumption of small amounts of protein and carbohydrates as part of an energy drink or whole food. Studies have shown this to be prudent behavior for anyone. Consuming quantities well above recommended levels, though not particularly dangerous, is most likely a futile gesture.

The full report entitled “Dietary Supplements and Sports Performance: Amino Acids,” by Melvin Williams, can be found in the Journal of the International Society of Sports Nutrition, Vol. 2(2), 2005.