A Specialized Multinutrient Formula Attenuates High-Fat-Diet-Associated Muscle Dysfunction and Sarcopenic Obesity-Related Features in Adult Mice.

Background/Objectives: Sarcopenia is an age-associated skeletal muscle disorder that may be aggravated by a high-fat diet (HFD). Given the multifactorial pathogenesis of sarcopenia, single-nutrient interventions may be insufficient. This study investigated whether a specialized multinutrient formula could attenuate muscle dysfunction and intramuscular lipid accumulation in adult mice under standard-diet and HFD-fed conditions. Methods: Male C57BL/6J mice were assigned to five groups: young control (YC), adult control (OC), adult control supplemented with the nutritional formula (OCN), adult HFD-fed mice (OH), and adult HFD-fed mice supplemented with the formula (OHN). A specialized multinutrient formula containing enriched whey protein, β-glucan, antioxidant vitamins, and essential trace minerals was orally administered five times per week for 12 weeks. Body composition, muscle histology, grip strength, intramuscular lipid accumulation, inflammatory gene expression, and protein markers related to caspase-associated apoptosis, proteolysis-related signaling, and tissue remodeling were assessed. Results: Compared with YC mice, adult control and HFD-fed mice exhibited reduced muscle strength and fiber cross-sectional area, increased adiposity, intramuscular lipid deposition, elevated TNF-α expression, and alterations in selected protein markers related to caspase-associated apoptosis, proteolysis-related signaling, and tissue remodeling. Nutritional supplementation improved muscle strength and fiber morphology, reduced intramuscular lipid deposition, lowered TNF-α expression, reduced cleaved caspase marker abundance, decreased p38 MAPK and MuRF-1 expression, and increased collagen type III expression. Conclusions: HFD aggravated muscle dysfunction and sarcopenic obesity-related features in adult mice, as evidenced by impaired muscle function, reduced muscle fiber cross-sectional area, increased intramuscular lipid accumulation, and changes in selected inflammatory, cleaved caspase-, protein turnover-related, and remodeling markers. Nutritional supplementation mitigated these alterations and improved muscle structure and function.