Plant-Based Dietary Patterns, Body Composition, Muscle Strength and Function in Middle and Older Age: A Systematic Review

Background Sarcopenia is prevalent in middle-aged and older adults. A plant-based diet may be linked to changes in body composition and musculoskeletal health. Objective This systematic review aimed to investigate the effects of plant-based dietary patterns on the body composition, muscle strength and function in middle-aged and older adults. PRISMA guidelines were followed. Method A systematic search was completed on databases including MEDLINE, Embase, Global Health, PREMEDLINE, Cochrane library, CINAHL and Scopus on articles published until 1st March 2019. Search terms included ‘middle-aged’, ‘older adult’, ‘plant-based diet’ and ‘muscle strength’. Title and abstract screening were conducted on 1,868 publications after deduplication. Sample size, subject characteristics, recruitment, inclusion and exclusion criteria, dietary measures, health outcome measures, statistical results and confounders were sorted by author, study type, year and country. The quality of evidence of extracted data was assessed using the Scottish Intercollegiate Guidelines Network (SIGN) and the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) tools. Results/Conclusions 17 papers were included from 31 articles selected for full review. The majority of the studies were cross-sectional studies (n = 9) and RCTs (n = 6). The remaining studies were cohort studies. Positive associations were found between plant-based dietary patterns; negative association with body composition; and inconclusive association with muscle function. However, further studies are needed to improve the understanding.