Nutritional interventions and dietary supplements in muscle diseases: a systematic review.

Abstract

Medical nutrition therapy significantly impacts cardiovascular risk and overall health, but effects on muscle diseases remain unclear. This systematic review evaluates the safety and efficacy of dietary interventions and supplements on muscle disease outcomes. A multidisciplinary team conducted a PRISMA-guided systematic review registered on PROSPERO. Searches were conducted across multiple databases and screened against pre-specified inclusion criteria. Of 107 full-text articles screened, 51 met inclusion criteria. Most identified interventions used dietary supplements rather than whole dietary approaches. In inflammatory myopathies, creatine (loading dose 20 g/day, maintenance 3 g/day) combined with exercise improved high-intensity functional performance in polymyositis and dermatomyositis over 6 months. In Duchenne muscular dystrophy, creatine (2-10 g/day for 8-16 weeks) improved maximal voluntary contraction and fatigue resistance. Carbohydrate-rich diets (65% CHO) reduced exercise-related symptoms in McArdle disease, while high-dose creatine (150 mg/kg/day) paradoxically worsened symptoms. Four trials of aceneuramic acid (6 g/day for 48 weeks) in GNE myopathy demonstrated dose-dependent strength improvements, leading to regulatory approval in Japan. High-protein supplementation showed positive trends for muscle preservation in critical illness myopathy. Quality assessment revealed 31% at low risk of bias, 49% with some concerns, and 20% at high risk. Evidence for nutritional interventions in muscle diseases remains limited, especially for inflammatory myopathies. The strongest support emerged for mechanistically targeted approaches: creatine with exercise, carbohydrate-rich and ketogenic diets in McArdle disease, and sialic acid in GNE myopathy. Future research requires adequately powered multicentre trials with standardised outcomes, with focus on inflammatory myopathies.