Sports drink producers are always trying to find new ways to give their products an edge over their competitors by adding various supplements that will enhance athletic performance. Rapidly digested protein supplements in the form of amino acids have been among the most recent trends in sports drinks, but the evidence that they truly boost performance is sketchy. However, a study by scientists from the University of São Paulo found that peptide glutamine supplementation may improve performance.
In the study, researchers were investigating whether supplementation of carbohydrate together with peptide glutamine would increase exercise tolerance in soccer players. They evaluated nine male soccer players, who by means of a draw, were assigned to one of two groups. The first group received a drink consisting of carbohydrate with peptide glutamine (50g of maltodextrin and 3.5g of peptide glutamine in 250 ml of water), or a drink consisting of carbohydrate alone (50g of maltodextrin in 250 ml of water).
Peptide glutamine contains about 30g of glutamine per 100g, created by the partial chemical breakdown of wheat protein. It is considered better than L-glutamine due to its amino acid structure, enhancing stability, and its ability to be more easily assimilated by the body.
Thirty minutes before starting each of two tests, taken one week apart, the athletes consumed their assigned sports drink. The tests consisted of a cardiopulmonary exercise test followed by an exercise protocol that simulated the movements of a soccer game in order to evaluate the athletes' tolerance to intermittent exercise.
When comparing the results from the two groups, researchers found that the group who had taken the carbohydrate/peptide glutamine drink had significantly greater exercise tolerance than the carbohydrate-only group. They covered an average of 15,571 metres as opposed to the carbohydrate-only group's 12,750 metres. In addition, total exercise duration was longer for the carbohydrate/peptide glutamine group at 88 minutes compared to 73 minutes for the other group. The group with the peptide glutamine supplementation also reported significantly lower levels of fatigue than the carbohydrate-only group.
The study consisted of a small sample of subjects, and the carbohydrate/peptide glutamine drink contained approximately 7% more calories than the pure carbohydrate drink, so further research is necessary to reach any definitive conclusions. However, the results of this study indicate that supplementation with peptide glutamine may be advantageous to athletes looking to boost their performance.