The Summary
This double-blind RCT investigated the effects of a 12-week resistance training program combined with leucine supplementation or a placebo in 19 pre-frail and frail older women. All participants consumed an optimized protein diet (1.2 g/kg/day). Researchers measured myofibrillar protein synthesis and muscle fiber size. The study found that resistance training significantly increased muscle protein synthesis, enlarged type 1 and 2a muscle fibers, and reduced frailty criteria by 64%. Surprisingly, adding 7.5 grams of leucine daily provided no additional anabolic benefits over resistance training alone.
Why this is interesting
Leucine is heavily marketed as a magic-bullet supplement for age-related muscle loss. However, this study reveals that when older women already consume optimal dietary protein, expensive leucine supplements offer zero extra benefit. Instead, the real cure for frailty is physical training. By reducing frailty criteria by over 60%, this research proves that consistent, progressive physical exercises remain the gold standard. For readers, it means prioritizing protein-rich foods and targeted physical training over trendy amino acid supplements to maintain youthfulness and independence.