ABSTRACT

Coffee, a widely consumed beverage, is a complex source of bioactive compounds, including caffeine, (poly)phenols, trigonelline, and diterpenes. Although habitual coffee consumption has been associated with metabolic benefits, its relationship with skeletal muscle (SM) health remains incompletely understood. The objective of the present scoping review was to map and characterise the available evidence on coffee and its main bioactive compounds in relation to SM health, including muscle mass, function, metabolic outcomes, and underlying molecular signalling pathways. In vitro, animal, and human studies examining coffee and coffee-derived bioactive compounds in relation to SM outcomes were included. A comprehensive search was conducted across eight electronic databases following PRISMA-ScR guidelines. Of the 21 108 records initially identified, 82 reports were assessed in full text after duplicate removal and title and abstract screening, and 54 studies were included in the scoping review. Data were charted and descriptively synthesised by study type, compound, and thematic domains. Evidence was predominantly derived from preclinical studies reporting effects on insulin signalling, oxidative stress, inflammation, mitochondrial function, and metabolic pathways in SM tissue. Direct assessments of muscle mass or quality were scarce. Evidence from human studies was mainly observational and based on heterogeneous outcome definitions. Preclinical findings support the biological plausibility that coffee and coffee-derived bioactive compounds may influence molecular pathways relevant to SM metabolism, particularly those related to mitochondrial function, oxidative stress, and glucose or lipid homeostasis. Evidence supporting clinically meaningful muscle-related outcomes in humans remains limited. Observational studies suggest that coffee consumption may be associated with lower prevalence of sarcopenia, frailty or related outcomes, although causality cannot be established. Important gaps persist regarding the lack of well-controlled human intervention studies using standardized muscle measurements and coffee composition.

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