Dietary phytochemicals as a promising nutritional strategy for sarcopenia: a systematic review and meta-analysis of randomized controlled trials

The decline in skeletal muscle mass and strength, also called sarcopenia, accelerates with age, leading to negative health outcomes and poor quality of life. Diet is important to promote health and plays a key role in muscle aging. Plant-based foods have recently received attention as sources of phytochemical components to attenuate loss of muscle mass and strength in older adults. This systematic review and meta-analysis evaluated the benefits of botanical extracts and their phytochemical compounds for muscle health in older adults. Randomized controlled trials were identified via systematic searches of four electronic databases (PubMed, Cochrane Library, Web of Science, and KoreaMed) up to June 2021 and were quality assessed. The results of muscle strength, mass, and physical performance were pooled using a random-effects model. Fourteen studies involving 528 subjects aged between 50 and 80 years met the inclusion criteria. Dietary phytochemicals significantly increased handgrip strength [0.90 kg; 95% confidence interval (CI) 0.26–1.53, p  =  0.01] and physical performance (timed up-and-go test: − 0.5 s, 2.73 times; 95% CI − 0.84 to − 0.15, p  <  0.01; 30-s chair stand test: 95% CI 0.88–4.59, p  <  0.01; 6-min walk test: 29.36 m; 95% CI 14.58–44.13, p  <  0.0001) but had no effect on improvement in muscle mass. Publication bias evaluated by funnel plots and Egger’s regression test demonstrated no evidence of substantial publication bias (p  >  0.05). The findings of this systematic review and meta-analysis suggest that phytochemicals are a potential nutritional strategy to improve muscle health in older adults.