The optimal regimen combining protein supplementation and exercise for sarcopenia among older adults: a network meta-analysis of randomized controlled trials

This study aimed to (1) compare the effects among different regimens combining variety of protein supplements and exercise therapies; (2) identify the optimal treatment option for sarcopenic indices.

The electronic databases were systematically searched from inception until July 2024. Randomized controlled trials (RCTs) that reported the effects of PS plus exercise for older people were identified. The included RCTs were analyzed through a frequentist network meta-analysis (NMA). Standard mean difference (SMD) with 95%CI was estimated for muscle mass, handgrip strength, and short physical performance battery (SPPB). The ranking probabilities for effect estimation among the treatments per outcome were expressed using surface-under-the cumulative-ranking (SUCRA) scores. Grading of Recommendations, Assessment, Development and Evaluations was used to evaluated certainty of evidence (CoE). Meta-regression analyses were performed to explore any potential moderators of the treatment efficacy and results were expressed as β with 95% credible interval (CrI).

We included 213 RCTs (9421 patients) for analyses. Among the 32 identified treatment options, whey plus resistance exercise yielded the highest probability in increasing muscle mass (SMD = 0.80; SUCRA = 0.91; CoE = moderate), handgrip strength (SMD = 0.88; SUCRA = 0.88; CoE = moderate), and SPPB function score (SMD = 0.83; SUCRA = 0.82; CoE = moderate). In addition, Participant’s age and PS dose were significant factors moderating the treatment efficacy on muscle mass (ꞵ = –1.46; 95% CrI: –2.28, –0.81) and handgrip strength (ꞵ = 0.78; 95% CrI: 0.34, 1.45), respectively.

Our findings suggest whey protein yields the optimal supplements to counter sarcopenia in older individuals undergoing resistance training. However, the treatment efficacy appears to be moderated by patient’s age and PS dosage.

Whey protein supplementation plus resistance-based exercise deems the optimal treatment regimen for older people, especially those with high sarcopenia and frailty risks. The results of this study may help the physical therapists to recommend the optimal nutrient supplements during exercise intervention for ensuring optimal treatment outcomes.