Protein Targets for Sarcopenia Prevention in Older Adults: Systematic Review and Meta-Analysis

Abstract

Introduction: Sarcopenia (age-related muscle loss) affects 15–20% of older adults. Optimal daily protein intake for prevention remains debated, with guidelines ranging 1.0–1.5 g/kg/day.
Methods: Systematic review and dose-response meta-analysis of 24 RCTs (n=3,102, age ≥65 years) comparing different protein intakes (0.8–1.6 g/kg/day) with or without resistance exercise. Outcomes: lean body mass (LBM) by DEXA or MRI, grip strength, gait speed, chair stand time.
Results: Protein >1.2 g/kg/day increased LBM by 0.8 kg (95% CI 0.4–1.2) compared to 0.8–1.0 g/kg/day, with no additional benefit above 1.5 g/kg/day. Grip strength improved by 2.1 kg (p=0.01) only when protein was combined with resistance exercise (≥2x/week). Whey protein was superior to plant protein for LBM gain (0.6 kg difference, p=0.02). Renal function was unchanged in patients without chronic kidney disease.
Discussion: Protein alone without exercise has minimal effect. Timing (post-exercise within 2 hours) enhances anabolic response.
Conclusion: Older adults should consume ≥1.2 g/kg/day protein, preferably whey, combined with resistance exercise for sarcopenia prevention.