Jan 29, 2015Wheying in on Protein
A new study indicates that whey protein may have an advantage over casein for muscle development. The research also shows that loading up with a single, larger dose immediately after exercise may be preferable to spacing out several small doses over a period of time post-workout.
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“A whey protein shake would probably be better than a casein protein shake,” Researcher Daniel W.D. West, a PhD student at McMaster University in Hamilton, Ontario, told WebMD.com. ”Casein is digested slowly, whereas whey is digested very rapidly.”
The study, published in the American Journal of Clinical Nutrition, used smaller doses of whey to mimic casein and compared them to a one-time dose of whey. Researchers gave both the one-time dose and the repeated doses to eight men, average age 22, during two different workouts. The men took the protein after doing eight sets of eight to 10 repetitions on a leg extension machine.
“What we did in this study is compare whey–25 grams, like [what is in] a typical protein shake–and compare it to 25 grams of whey, but ingested in little 2.5 gram shots,” said West, who noted that the amino acid concentrations in the men’s blood were higher after one big dose.
So why was it higher?
“Whey is high in leucine and the fact that it is rapidly digested means there is a rapid appearance of essential amino acids, including leucine,” West said. “Those amino acids act as a signal to elevate muscle protein synthesis–crucial for ongoing growth, repair, and maintenance of muscles.”
A separate study, also published in the American Journal of Clinical Nutrition, found protein that includes a higher concentration of the amino acid leucine works better than protein with lower concentrations. Researchers examined seven men and one woman who were all active duty members of the military with an average age was 24.
In the study, subjects twice pedaled on an exercise bike for an hour at moderate intensity, after which they drank a high-protein beverage with 10 grams of protein. According to Stefan M. Pasiakos, PhD, a research physiologist with the U.S. Army Research Institute of Environmental Medicine, the concentration of the amino acid leucine in the drink was different for each session, with one drink containing about 19 percent leucine and the other 35 percent.
Pasiakos told WebMd that muscle protein synthesis was 33 percent greater after consumption of the leucine-enriched protein beverage than after the lower-leucine drink. “It appears more leucine is beneficial in the context of muscle recovery,” he said.
According to Felicia Stoler, RD, a nutritionist and exercise physiologist who reviewed the study findings for WebMD, despite each study’s findings, athletes should not overdo protein consumption after exercise. “Some protein for repair is good but not excess. I always have to caution about protein,” she told WebMD. “People think they need way more than they do.”
So how much do they need? According to a 2009 position paper from the American College of Sports Medicine and the American Dietetic Association, endurance and strength-trained athletes ranges should typically consume 0.5 to 0.8 grams per pound of body weight. So, a 120-pound person would need about 60-96 grams and 150-pound person would need 75-120 grams or more.
For more information, check out the T&C feature, “A Closer Look.” In the article, Janet Walberg Rankin, PhD, a Professor in the Department of Human Nutrition, Foods, and Exercise at Virginia Tech, talks with leading nutrition researchers about with protein sources are best, and protein’s role in recovery.
R.J. Anderson is the Online Editor at Training & Conditioning.
