Nutritional Intervention Improves Muscle Mass and Physical Performance in the Elderly in the Community: A Systematic Review and Meta-Analysis.

Nutritional supplements have been extensively used as health interventions for the elderly. However, with the spread of COVID-19, no consensus exists on whether nutritional interventions could improve muscle mass and physical activity in community-dwelling older adults. To conduct a systematic review and meta-analysis to explore the effects of different nutritional interventions on muscle mass and physical performance in the elderly, we searched , , , and databases from their founding dates to December 2023. The meta-analysis was performed using RevMan5.3 software. Only randomized controlled trials (RCTs) were considered, and the overall mean difference (MD) or standardized mean difference (SMD) with 95% confidence interval (CI) was calculated. There were 33 studies comprising 3579 elderly persons meeting the inclusion criteria. Comprehensive analysis suggested that the intervention effect of fat-free mass (FFM), appendix skeletal muscle mass (ASMM), handgrip strength (HGS), gait speed, and short physical performance battery (SPPB) score was higher in the nutritional supplement group than in the control group. The results of subgroup analysis demonstrated that protein supplementation (SMD = 0.82, < 0.0001) had an optimal effect on ASMM (SMD = 0.89, < 0.0001) and FFM (MD = 2.09, < 0.0001) in the elderly. Vitamin D supplementation (SMD = 0.52, < 0.0001) had a marginal effect on ASMM, and energy supplementation (SMD = 0.39, = 0.0005) had the lowest effect. Moreover, nutritional interventions had the most significant impact on HGS (MD = 1.06, < 0.0001) and TUG (MD = 0.14, < 0.0001) in individuals aged 65-75 years old, with positive effects on FFM (MD = 1.62, < 0.0001) and HGS (MD = 0.82, < 0.0001) when compared to healthy elderly individuals, and had greater effect on ASMM (SMD = 0.69, < 0.0001) than on the elderly with sarcopenia. Nutritional supplements can enhance muscle mass and physical performance in the elderly, while protein is recommended for muscle function. The golden period for implementing nutritional interventions to improve muscle function is before the age of 75 years. However, the impact of nutritional interventions varies with age and population. Given the limited evidence on nutritional interventions, more detailed and high-quality studies are highly warranted in the future.