Want to get more muscle-building benefits from your protein shake? Then blend your protein powders, suggests a new study published in the Journal of Applied Physiology.
First, a primer on protein digestion: soy, whey and casein deliver protein differently. Soy is a “complete” protein, which means it has all the vital amino acids you need. Whey accounts for 20% of the protein found in milk; it digests quickly, making it valuable at those times when you need to get protein to your muscles quickly, such as after a workout. And, finally, casein makes up 80% of the protein found in milk; it has the ability to slow protein catabolism in the body and the resulting muscle breakdown. The idea is: if you digest a blend of proteins that have different digestion rates, it would prolong amino acid (the build blocks of muscle) availability, increase muscle protein synthesis and thus, build more muscle.
To assess whether this is the case, researchers at the University of Texas Medical Branch (UTMB) had 16 healthy subjects consume either a protein shake made with a soy-dairy blend (25% isolated DuPont Danisco SUPRO soy protein, 50% caseinate, 25% whey protein isolate) or a single protein source (whey protein isolate) one hour after strength training. Muscle biopsies were taken before the study and up to five hours after exercise.
The result: The soy-dairy blend shake delivered an increase of amino acids for about an hour longer than the whey-only shake. In addition, those who drank the protein blend had greater amino acid balance than those who consumed the whey—suggesting that less muscle protein breakdown was occurring.
More research is still needed to figure what the long-term effects on muscle mass and strength protein blending can have. In the meantime, there’s no reason not to shake up your post-workout shake with a custom blend of your own. Our tip: pair flavored with non-flavored powders.