Adding Leucine to Whey
Research & Development
By Jeff Volek - Chat with Doug on the ProSource Fitness Forum
Jun 1, 2012
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Dose response studies indicate that about 25 grams of high quality intact protein delivers maximizes the increase in muscle protein synthesis. Twenty five grams of whey protein contains about 3 grams of leucine.
Since leucine is the primary driver of muscle protein synthesis, it might be possible to elicit a maximal increase in muscle protein synthesis by taking less whey and adding free leucine. At least that's the question Canadian researchers hoped to answer. They measured muscle protein synthesis rates after subjects ingested either 25 grams of whey protein isolate (containing 3 grams of leucine) or 6.25 grams whey protein with extra leucine added to bring it up to the same amount in the 25 gram dose. Compared to fasting, rates of muscle protein synthesis up to 5 hours after feeding were significantly increased but similar between 25 grams of whey and the 6.25 grams of whey + leucine conditions. However when comparing these two conditions 3-5 hours after resistance exercise, consuming 25 grams of whey resulted in nearly a two-fold greater increase in muscle protein synthesis. The implications of these findings are that adding extra leucine to smaller amounts of whey can provide benefits similar to larger amounts of whey during rest (non-exercising conditions), but that 25 grams of whey provides a more sustained increase in muscle protein synthesis after resistance exercise.
Churchward-Venne TA, Burd NA, Mitchell CJ, West DW, Philp A, Marcotte GR, Baker SK, Baar K, Phillips SM. Supplementation of a suboptimal protein dose with leucine or essential amino acids: effects on myofibrillar protein synthesis at rest and following resistance exercise in men. J Physiol. 2012 Mar 25.
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