Improved Muscle Mass and Function With Protein Supplementation in Older Adults With Sarcopenia: A Meta-Analysis

OBJECTIVE: To systematically review the effects of protein supplementation in older adults with sarcopenia. METHODS: A systematic literature search was conducted in PubMed, Cochrane Library, and Embase databases until May 2023. The inclusion criteria were as follows: (1) randomized controlled trials with a quantitative study design; (2) studies with a study group of older adults with sarcopenia; (3) studies comparing muscle mass, muscle strength, and performance of older adults with sarcopenia after protein supplementation; and (4) studies published up to May 2023. RESULTS: Six retrospective comparative studies, including 715 patients, met the inclusion criteria. The nutritional supplementation group exhibited significant improvement in appendicular skeletal muscle mass (standardized mean difference [SMD]=0.41; 95% confidence interval [CI], 0.24–0.58; p<0.001; I(2)=1%), while handgrip strength (SMD=0.37; 95% CI, -0.32–1.07; p=0.29; I(2)=94%) and Short Physical Performance Battery (SPPB) (SMD=0.35; 95% CI, -0.47–1.18; p=0.40; I(2)=94%) showed a tendency for improvement. CONCLUSION: Nutritional supplementation with protein increased appendicular muscle mass in older adults with sarcopenia and improved handgrip strength and SPPB scores.