Comparative Effectiveness of Nutritional Strategies for Sarcopenia-Related Outcomes in Older Adults: A Systematic Review and Network Meta-Analysis

Objective: This study compared the relative effects of distinct nutritional strategies on muscle mass, muscle strength, and physical performance in older adults with sarcopenia or at high risk of sarcopenia. Methods: PubMed, Embase, the Cochrane Library, Web of Science, and CNKI were systematically searched for randomized controlled trials (RCTs). Random-effects pairwise meta-analysis and network meta-analysis (NMA) were performed. The surface under the cumulative ranking curve (SUCRA) was used to summarize relative rankings, and CINeMA was applied to assess the certainty of evidence. Results: Twenty RCTs involving 2160 participants were included, forming 17 network nodes. Nutritional interventions collectively improved appendicular skeletal muscle mass index (ASMI), grip strength, and gait speed, whereas the pooled effect on the five-times sit-to-stand test (5STS) was not statistically significant. In the NMA, whey protein + vitamin D + leucine improved ASMI (SMD = 0.29, 95% CI: 0.06 to 0.52) and grip strength (SMD = 0.82, 95% CI: 0.13 to 1.50), and it reduced 5STS completion time (SMD = −1.41, 95% CI: −2.63 to −0.18). Omega-3 fatty acids + leucine + Lactobacillus paracasei PS23 improved ASMI (SMD = 0.67, 95% CI: 0.10 to 1.25) and grip strength (SMD = 1.84, 95% CI: 0.39 to 3.28), although this node was supported by a single RCT. Leucine + vitamin D + medium-chain triglycerides improved gait speed (SMD = 1.28, 95% CI: 0.13 to 2.43), although this node was also supported by a single RCT. Sensitivity analyses indicated that the magnitude and precision of some formulation-specific estimates varied with the exclusion of individual trials or restriction to participants with confirmed sarcopenia. The certainty of evidence for the principal comparisons ranged from low to very low. Conclusions: Nutritional supplementation showed overall benefits for ASMI, grip strength, and gait speed, while formulation-specific effects varied across outcomes. Whey protein + vitamin D + leucine showed favorable effects across several outcomes, whereas omega-3 fatty acids + leucine + Lactobacillus paracasei PS23 and leucine + vitamin D + medium-chain triglycerides showed additional formulation-specific signals based on single-study nodes. Given the sparse network and very low certainty of evidence for the principal comparisons, these findings should be regarded as candidate signals rather than evidence of a definitive treatment hierarchy.