Post-exercise protein drinks help muscles

HAMILTON, Ontario, Aug. 19 (UPI) -- Two independent studies help explain how amino acids in protein drinks help muscles in recreational athletes, U.S. and Canadian researchers say.

In the first study, study leader Stuart Phillips of McMaster University in Hamilton, Ontario, investigated whether post-exercise muscle protein synthesis is different when a large, single dose of whey protein of about 1 ounce is consumed immediately after activity, compared with when smaller doses -- 0.09 ounce -- are consumed 10 times over an extended period.

"The idea with the small 'protein shots' was to mimic how another milk protein, casein, is digested. Participants -- eight men; mean age of 22 -- performed eight sets of eight repetitions on a leg-extension machine; each subject participated in both dietary treatment regimens," Phillips says.

In the second study, study leader Stefan Pasiakos of the U.S. Army Research Institute of Environmental Medicine, had active-duty military personnel -- seven men and one woman with a mean age of 24 -- consumed a high-protein beverage with 10 grams of protein as essential amino acids containing 1.87 or 3.5 grams of leucine, an amino acid, while exercising on a stationary bicycle.

Consumption of the large dose of whey protein immediately after exercise increased muscle protein synthesis more than the smaller periodic doses of protein. In the second study, muscle protein synthesis was 33 percent greater after consumption of the leucine-enriched protein beverage than after the lower-leucine drink.

The studies, published in The American Journal of Clinical Nutrition, conclude that muscle metabolism after exercise can be manipulated via dietary means.