Influence of 8 Weeks of Whey-Protein and Leucine Supplementation on Physical and Cognitive Performance

• Published in: International journal of sport nutrition and exercise metabolism 2010-10, Vol.20 (5), p.409-417
• Main Authors: Walker, Thomas B, Smith, Jessica, Herrera, Monica, Lebegue, Breck, Pinchak, Andrea, Fischer, Joseph
• Format: Article
• Language: English
• Subjects: Absorptiometry, Photon; Adaptation, Physiological - drug effects; Adaptation, Physiological - physiology; Adult; Analysis of Variance; body composition; Body Composition - drug effects; Body Composition - physiology; cognition; Cognition - drug effects; Cognition - physiology; Dietary Proteins - metabolism; Dietary Proteins - pharmacology; Dietary Supplements; Double-Blind Method; exercise; Exercise - physiology; exercise test; health status; Humans; leucine; Leucine - metabolism; Leucine - pharmacology; Male; men; Military Personnel; Milk Proteins - metabolism; Milk Proteins - pharmacology; muscle strength; Muscle Strength - drug effects; Muscle Strength - physiology; Muscle, Skeletal - drug effects; Muscle, Skeletal - growth & development; physical performance; sports nutrition; whey protein; Whey Proteins; women
• ISSN: 1526-484X; 1543-2742
• DOI: 10.1123/ijsnem.20.5.409

The purpose of this study was to investigate the ability of whey-protein and leucine supplementation to enhance physical and cognitive performance and body composition. Thirty moderately fit participants completed a modi­fied Air Force fitness test, a computer-based cognition test, and a dual-energy X-ray-absorptiometry scan for body composition before and after supplementing their daily diet for 8 wk with either 19.7 g of whey protein and 6.2 g leucine (WPL) or a calorie-equivalent placebo (P). Bench-press performance increased significantly from Week 1 to Week 8 in the WPL group, whereas the increase in the P group was not significant. Push-up performance increased significantly for WPL, and P showed a nonsignificant increase. Total mass, fat-free mass, and lean body mass all increased significantly in the WPL group but showed no change in the P group. No differences were observed within or between groups for crunches, chin-ups, 3-mile-run time, or cognition. The authors conclude that supplementing with whey protein and leucine may provide an advantage to people whose performance benefits from increased upper body strength and/or lean body mass.