By Robbie Durand Generation Iron
Kick your muscle production up a notch.
Leucine is a key amino acid involved in the regulation of skeletal muscle protein synthesis. Leucine triggers the anabolic mTOR pathway, which is essential for muscle growth; additionally, leucine has proven to build muscle, maintain lean mass when in a caloric deficit, improve endurance, and boost recovery. Researchers wanted to examine how adding leucine to a protein drink would affect muscle protein synthesis. Researchers assessed the effect on muscle protein synthesis at rest and after resistance exercise. The men completed unilateral knee extensor resistance exercise before the ingestion of various intakes of whey protein, BCAAs, and leucine:
The subjects received either:
-25 g whey protein (W25) (3.0 g leucine)
-6.25 g whey protein (W6) (0.75g leucine)
-6.25 g whey protein supplemented with leucine to 3.0 g total leucine
-6.25 g whey protein supplemented with leucine to 5.0 g total leucine
-6.25 g whey protein supplemented with leucine, isoleucine, and valine to 5.0 g total leucine.
The researchers found that muscle protein synthesis remained above baseline after all treatments but was greatest after 25 grams of whey and 6.25 grams whey protein supplemented with leucine to five grams total leucine (low-protein/high leucine group). The really interesting finding was the low protein (6.25 grams) mixed beverage was as effective as a high-protein whey (25 grams) shake at stimulating increased muscle protein synthesis rates when supplemented with a high amount of leucine (five grams). These results, indicating that high leucine can have enhanced muscle anabolism effects, are important for athletes who are on a strict diet and cutting back on total calories.
Churchward-Venne TA, Breen L, Di Donato DM, Hector AJ, Mitchell CJ, Moore DR, Stellingwerff T, Breuille D, Offord EA, Baker SK, Phillips SM. Leucine supplementation of a low-protein mixed macronutrient beverage enhances myofibrillar protein synthesis in young men: a double-blind, randomized trial. Am J Clin Nutr. 2014 Feb;99(2):276-86.