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Jennifer Grebow is editor-in-chief of Nutritional Outlook.
For the first time, Sustamine’s effects were tested when consumed in an electrolyte-containing rehydration sports drink.
Studies indicate that the amino acid L-glutamine enhances water and electrolyte absorption-a key boon for sports performance. Research also shows that Sustamine, a branded L-alanyl-L-glutamine dipeptide ingredient, is absorbed up to 200% better than standard L-glutamine itself. For purposes of sports nutrition, however, Sustamine’s effects have never been tested when consumed in an electrolyte-containing rehydration sports drink. In a recent study, University of Central Florida researchers explored whether adding low and high doses of Sustamine to a Gatorade G2 beverage helped trained endurance athletes run longer before becoming exhausted.
The study was performed on 12 endurance-trained men. Subjects were tested on four separate occasions separated by a one week–minimum washout period. During each trial, subjects were first made to run for one hour at 75% of their VO2 peak (milliliters of oxygen per body weight utilized per minute) and were then asked to run to exhaustion at 90% of their VO2 peak.
During one trial, subjects did not hydrate with any beverage. During another trial, during the one-hour run, they consumed 1 L of Gatorade alone (250 ml every 15 minutes). In the two other trials, subjects drank the Gatorade beverage, but this time supplemented with either a low (600 mg/L) or high (2 g/L) dose of Sustamine.
Compared to no hydration, there was a significant difference in time to exhaustion when subjects consumed the drinks containing either the low or high dose of Sustamine.
But researchers found only a 12.7% improvement in time to exhaustion with the high-dose Sustamine drink compared to the no-Sustamine drink, which they said was not a statistically significant difference, suggesting “that rehydration alone may have accounted for a majority of the improvement in run performance.”
Still, they noted, “this 12.7% improvement in performance could make a difference in a competitive endurance event.”
The researchers did find that plasma glutamine concentrations were significantly higher at 45 minutes into the Sustamine trials; during the high-dose test, these levels remained higher throughout the one-hour run, indicating that a higher dose of glutamine may be necessary to sustain higher glutamine levels beyond 45 minutes of exercise.
“For endurance athletes such as long-distance runners, the addition of Sustamine in hydration protocols may allow for longer times before exhaustion sets in,” concluded one of the study researchers, Jay Hoffman, PhD, and a professor of sports and exercise at the University of Central Florida, in a press release.
Sustamine is supplied by Kyowa Hakko USDA (New York City), which sponsored the study.
Nutritional Outlook magazine
McCormack WP et al., “Effects of l-Alanyl-l-Glutamine ingestion on one-hour run performance,” Journal of the American College of Nutrition. Published online June 22, 2015.