Nutritional interventions to improve muscle mass, muscle strength, and physical performance in older people: an umbrella review of systematic reviews and meta-analyses

peer reviewedContext: Sarcopenia is a progressive and generalized skeletal muscle disorder associated with an increased risk of adverse outcomes such as falls, disability, and death. The Belgian Society of Gerontology and Geriatrics has developed evidencebased guidelines for the prevention and treatment of sarcopenia. This umbrella review presents the results of the Working Group on Nutritional Interventions. Objective: The aim of this umbrella review was to provide an evidence-based overview of nutritional interventions targeting sarcopenia or at least 1 of the 3 sarcopenia criteria (ie, muscle mass, muscle strength, or physical performance) in persons aged 65 years. Data sources: Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, the PubMed and Web of Science databases were searched for systematic reviews and meta-analyses reporting the effect of nutritional supplementation on sarcopenia or muscle mass, strength, or physical performance. Data extraction: Two authors extracted data on the key characteristics of the reviews, including participants, treatment, and outcomes. Methodological quality of the reviews was assessed using the product A Measurement Tool to Assess Systematic Reviews. Three authors synthesized the extracted data and generated recommendations on the basis of an overall synthesis of the effects of each intervention. Quality of evidence was rated with the Grading of Recommendations Assessment, Development and Evaluation approach. Data analysis: A total of 15 systematic reviews were included. The following supplements were examined: proteins, essential amino acids, leucine, b-hydroxy-b-methylbutyrate, creatine, and multinutrient supplementation (with or without physical exercise). Because of both the low amount and the low to moderate quality of the reviews, the level of evidence supporting most recommendations was low to moderate. Conclusions: Best evidence is available to recommend leucine, because it has a significant effect on muscle mass in elderly people with sarcopenia. Protein supplementation on top of resistance training is recommended to increase muscle mass and strength, in particular for obese persons and for >=24weeks. Effects on sarcopenia as a construct were not reported in the included reviews