L-Alanyl-L-Glutamine helps dehydrated athletes to better times
A dipeptide protects endurance athletes from performance loss through dehydration. A team of sports scientists from the College of New Jersey has demonstrated the ergogenic effect of L-alanyl-L-glutamine [structural formula below] in a study published in the Journal of the International Society of Sports Nutrition.
L-Alanyl-L-Glutamine is a compound that has been much studied by Japanese companies. One of the big manufacturers is Kyowa Hakko, which together with the Japanese Ajinomoto is the market leader in amino acids. Hyowa Hakko markets L-alanyl-L-glutamine as Sustamine. Interest in Sustamine rose in 2009, when the American Halo Labs launched Code Blue Recovery Drink on to the market. This contains L-alanyl-L-glutamine.
In animal studies L-alanyl-L-glutamine enhances the uptake of water. [Nutrition. 2002 Jun; 18(6): 458-62.] That's why the researchers wanted to know whether the dipeptide had the same effect in humans, or more to the point, in athletes. In hot weather athletes lose large quantities of fluid. And that loss frequently causes a noticeable decline in performance.
The researchers devised an experiment with 10 male students. The subjects had to cycle as long as they could a number of times, at 75 percent of their VO2max. On one occasion the subjects’ fluid level was healthy [T1], on another occasion they had first lost 2.5 percent of their bodyweight through dehydration [T2]. In test T3 the subjects had replenished their fluid loss by 1 percent of their bodyweight using ordinary water; and on two other occasions they replenished their fluid loss with water in which L-alanyl-L-glutamine had been dissolved.
In test T4 the subjects received 0.05 g L-alanyl-L-glutamine per kg bodyweight, and in test T5 the amount was 0,2 g/kg. For an imaginary athlete weighing 70 kg, that would amount to 3.5 or 14 g L-alanyl-L-glutamine.
The figure below shows the amount of time the subjects managed to cycle for. The lower figure shows the difference in the times for the control trial T1 on the one side and on the other the partial dehydration trials T2, T3, T4 and T5.
Dehydration reduced the amount of time the subjects were able to cycle by more than 7 minutes. When the subjects drank ordinary water the time was reduced by just less than 5 minutes. Water containing the dipeptide worked better. The most effective dose of L-alanyl-L-glutamine was 0.05 g/kg. This reduced the time loss to just 2 minutes.
The researchers measured their subjects' hormone and interleukins levels, but found nothing that could explain the improvement in performance. They confine themselves to saying that the dipeptide improves water uptake. From their literature reading they suggest that L-alanyl-L-glutamine helps the gut cells to absorb more water from the food passing through, and the muscle cells to absorb more water from the blood.
J Int Soc Sports Nutr. 2010 Feb 3; 7:8.
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