Precision Nutrition for Prevention of Skeletal Muscle Atrophy and Bone Loss during Long-Duration Human Spaceflight: A Review

Long-duration human spaceflight produces profound physiological adaptations because of microgravity, radiation exposure, confinement, altered circadian rhythms, restricted food systems and psychological stress. Among the major health concerns are skeletal muscle atrophy and accelerated bone loss, which may compromise physical performance, mobility and long-term health during extended missions to the Moon and Mars. Nutrition is an important component of countermeasure strategies because inadequate energy intake, insufficient protein and altered calcium and vitamin D metabolism can intensify musculoskeletal deterioration. Conventional nutritional recommendations, however, may not fully account for the considerable inter-individual variation in metabolic responses to spaceflight. Precision nutrition offers an emerging approach in which dietary strategies may be adapted according to individual characteristics including body composition, energy expenditure, nutrient status, metabolic responses, genetic variation, microbiome composition and exercise response. This review examines the physiological basis of muscle and bone deterioration during spaceflight and evaluates the roles of energy, protein, amino acids, calcium, vitamin D, vitamin K, omega-3 fatty acids, antioxidants, fibre, probiotics and functional foods. Evidence relating to nutrient stability, food acceptability and food-system limitations is also considered. The review further discusses the potential application of genomics, transcriptomics, proteomics and metabolomics to individualise nutritional interventions. Current evidence supports an integrated approach combining adequate energy and protein intake, resistance exercise, micronutrient adequacy, food acceptability and continuous physiological monitoring. Nevertheless, direct evidence for precision nutrition interventions in astronauts remains limited and several proposed strategies are based on terrestrial, analogue or experimental models. Future research should therefore focus on validated biomarkers, longitudinal astronaut datasets and practical personalised nutritional protocols suitable for long-duration exploration missions.