Vitamin D and resveratrol in sarcopenic obesity: a systematic review highlighting the gap in phenotype-defined randomized controlled trials

Background: Sarcopenic obesity (SO) is an inflammatory-metabolic condition characterized by the coexistence of excess adiposity and impaired skeletal muscle mass and function. Vitamin D and resveratrol modulate regulatory pathways implicated in SO pathophysiology, including NF-κB signaling, PGC-1α, mitochondrial regulation, and redox balance. Whether this mechanistic rationale has translated into phenotype-defined randomized clinical trials remains unclear. Methods: We conducted a systematic dual-track search across PubMed, Scopus, and Web of Science to identify randomized controlled trials (RCTs) evaluating isolated vitamin D or resveratrol supplementation in adults with explicitly defined sarcopenic obesity or meeting implicit SO phenotype criteria, defined as the concurrent presence of adiposity and objective muscle impairment at baseline. Trials lacking confirmation of both components at enrollment were excluded. Risk of bias was assessed using Cochrane RoB 2.0. Results: = 0). Retrieved RCTs in related populations did not simultaneously require adiposity and muscle impairment as enrollment criteria. As a result, no phenotype-defined interventional evidence specific to sarcopenic obesity was identified. Conclusion: Despite compelling mechanistic convergence, randomized interventional evidence in strictly defined sarcopenic obesity populations is currently lacking. Future RCTs must adopt phenotype-defined enrollment strategies integrating adiposity, muscle dysfunction, and mechanistic endpoints to determine whether micronutrient signaling can meaningfully modify outcomes in SO. Systematic review registration: https://www.crd.york.ac.uk/PROSPERO/view/CRD420261307248, identifier PROSPERO (CRD420261307248).