Today at Experimental Biology 2012, Dr. Blake Rasmussen and colleagues presented a new and first-of-its-kind clinical study: "Effect of Protein Blend vs. Whey Protein Ingestion on Muscle Protein Synthesis Following Resistance Exercise." The results of this study suggest that a protein blend (combination of soy, whey and casein) may be best to consume post-workout for building muscle. Specifically, the blend of proteins in this study showed an increase in a person's "anabolic window" (the amount of time it takes for building muscle to occur post exercise).
"This study confirms that consuming a blend of proteins (soy, whey and casein) versus whey protein alone provides a prolonged delivery of amino acids to the muscles, making it optimal for consumption following resistance exercise," said Dr. Rasmussen, professor and interim chair of the Department of Nutrition & Metabolism at the University of Texas Medical Branch and the senior author of this study. "The results of this study are critical for sports nutrition consumers and regularly active individuals."
The protein in the blend used in this study consisted of 25 percent isolated soy protein, 25 percent isolated whey protein and 50 percent casein. This combination of protein blends was determined in a preclinical study, of which was presented at Experimental Biology 2011.
Soy, whey and casein proteins are all absorbed at different rates during digestion. Whey protein is referred to as a "fast" protein because it is rapidly absorbed whereas casein, a "slow" protein, requires several hours to be digested. The ability of soy protein to deliver amino acids is "intermediate," meaning concentrations in blood peak somewhat later compared to whey, but its digestion rate is much quicker than casein. Hence, the effect of all three of these proteins combined appears to provide the extended release of amino acid delivery to the muscles.
"Your muscles don't recover in 30 minutes. It takes at least 24-48 hours for your muscles to recover after a resistance exercise," said Greg Paul, global marketing director for sports nutrition and weight management, Solae. "This study showed that protein blends can provide amino acid delivery for up to five hours, meaning if you consume a product or protein shake with these blends, the prolonged effect will deliver essential amino acids to feed your muscles until your next meal."
This was a double-blind, randomized clinical trial in nineteen young adults before and after ingestion of ~19 grams of protein from the blend or ~17.5 grams of whey protein (10 and 9, respectively, per group).
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