Leucine supplementation enhances integrative myofibrillar protein synthesis in free-living older men consuming lower- and higher-protein diets: a parallel-group crossover study.

Study answer

What this study found

Leucine co-ingestion increased integrated myofibrillar protein synthesis versus placebo in both rested and resistance-exercise conditions, with no meaningful difference between the lower-protein and higher-protein groups. In the rested condition, MyoPS was 1.57% ± 0.11%/d with leucine versus 1.48% ± 0.08%/d with placebo (P < 0.001); after resistance exercise, it was 1.87% ± 0.09%/d versus 1.71% ± 0.10%/d (P < 0.001). The authors concluded that leucine also amplified the anabolic response to resistance exercise and may be a practical strategy to help maintain muscle mass in older adults. No…

Study & population

Parallel-group crossover study in 20 generally healthy, community-dwelling older men aged 65-85 years in Hamilton, Ontario, Canada.

Intervention

Leucine was provided orally as a taste-matched beverage, 5 g per meal, taken midway through each of 3 daily main meals (breakfast, lunch, and dinner) for 3 days (days 3-5 of the treatment period).

Key limitation

Small sample size with 10 participants per active arm, short 3-day supplementation window, and a narrow population of healthy older men limit generalizability.

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Original abstract