Eating protein -- before or after exercise?
New York, December 1, 2010
Having that protein shake right after exercising may help build muscle in both younger and older men, a recent study said.
Muscle protein increased at nearly the same rate in both young and elderly men, according to the study.
This suggests that, contrary to some research speculation, older age may not impair the way the body digests and absorbs protein from food, wrote study leader Luc JC van Loon of Maastricht University Medical Center in the Netherlands.
'Effective dietary approaches are needed to prevent and/or attenuate the age-related loss of muscle mass,' van Loon and his colleagues said.
The study, carried in the American Journal of Clinical Nutrition, included 24 older men with an average age of 74 and 24 young men with an average age of 21, none of whom regularly exercised.
Researchers randomly assigned the men to two groups. In one, the men rested for 90 minutes, followed by 30 minutes of exercise -- pedaling a stationary bike and performing light strengthening exercises. In the other group, the men spent those additional 30 minutes relaxing.
Afterwards, men in both groups drank a solution containing 20 grams of protein, then had their blood levels of various amino acids repeatedly measured. The researches also took a small sample of tissue from each man's thigh muscle, right before the protein drink and 6 hours afterward, to measure protein changes in the muscle.
Overall, muscle protein increased to a greater extent in the exercise group than the inactive group, for both older and younger men.
But the study has limitations, such as the small size. In addition, it did not look at actual muscle mass changes over time but only short-term changes in participants' muscle-fiber proteins after the protein drink. – Reuters