Caffeine intake is nonlinearly associated with muscle mass in young and middle-aged US adults

Recent studies have indicated that coffee consumption is inversely correlated with sarcopenia in the elderly population. Data regarding the association between caffeine intake and muscle mass in young adults are scarce. We aimed to investigate how dietary caffeine correlates with muscle mass and sarcopenia in the young and middle-aged people. We performed a cross-sectional study utilizing data from NHANES. Muscle mass was evaluated using DXA and caffeine intake was derived from 24-h dietary recalls. Multivariable regression analysis was adopted to explore association between caffeine and sarcopenia. Restricted cubic spline analysis was conducted to investigate dose-response effect of dietary caffeine on muscle mass. Mediation effect of high-sensitivity C reactive protein was examined by mediation analysis. A total of 9116 adults aged from 20 to 59 years old were included. Higher ingestion of caffeine was not associated with sarcopenia. Association between dietary caffeine and muscle mass was found to be W-shaped in males and U-shaped in young females, wherein mediation effect of hs-CRP was not discovered. Caffeine consumption is associated with muscle mass in a nonlinear pattern. ASMI peaks at a daily caffeine intake of 1.23 mg/kg in young adults, while 0.64-1.49 mg/kg is recommended for middle-aged men.