Effects of Protein Intake and Muscle-Strengthening Exercise Participation on Sarcopenia and Metabolic Syndrome among Korean Older Adults: Based on the 9th Korea National Health and Nutrition Examination Survey(KNHANES)

This study examined the combined associations of dietary protein intake and resistance exercise with metabolic syndrome and sarcopenia-related indicators in Korean older adults. Using Korea National Health and Nutrition Examination Survey (KNHANES) 2022–2024 data, 1,526 adults aged ≥65 years were analyzed. Protein intake was classified as low (<1.2 g/kg/day; Low protein, LP) or adequate (≥1.2 g/kg/day; Adequate protein, AP), and resistance exercise as non-participation (<2 days/week; No Resistance Exercise, NoRE) or participation (≥2 days/week; Resistance Exercise, RE), yielding four groups (LP&NoRE, AP&NoRE, LP&RE, AP&RE). Survey-weighted ANCOVA and logistic regression were performed after adjusting for age, sex, smoking, alcohol use, and BMI. Compared with LP&NoRE, resistance-exercise groups showed higher handgrip strength and ASMI, with the highest values observed in AP&RE group. Adjusted odds of metabolic syndrome were lower in LP&RE (Odds Ratio [OR] 0.572; 95% Confidence Interval [CI] 0.383–0.853) and lowest in AP&RE (OR 0.359; 95% CI 0.217–0.593). These findings suggest that adequate protein intake combined with regular resistance exercise may contribute to improved metabolic and muscle health in older adults.