Optimal Vitamin C Status is Associated with Better Physical Performance in Men and Women from the EPIC-Norfolk Cohort: A Cross-Sectional Study

Abstract Vitamin C may be important for maintaining skeletal muscle health and preventing sarcopenia, but most previous epidemiological studies have investigated dietary intakes rather than vitamin C status. To address this gap, this study investigated cross-sectional associations between both plasma and dietary vitamin C and muscle strength and physical performance. This study analysed data from over 5000 participants of the European Prospective Investigation into Cancer and Nutrition (EPIC)-Norfolk cohort (aged 48–92 years). Multivariable linear regression models, adjusted for lifestyle, biological, medical, and dietary covariates, were used to investigate associations between dietary (categorised as quintiles, Qs) and plasma vitamin C (low < 25μmol/L, suboptimal 25 to < 50μmol/L, optimal ≥ 50μmol/L), and handgrip strength (adjusted for height: HGS ht ), gait speed, and 5-chair-stand time. Least square means for outcome measures were calculated from regression models. Women with optimal versus low plasma vitamin C had higher HGS ht (+ 0.54 kg/m 2 , p = 0.009), and faster gait speed and chair-stand time (+ 0.11m/s, p < 0.001; − 1.03s, p = 0.028, respectively). Men with optimal versus low plasma vitamin C had faster gait speed and chair-stand time (+ 0.05m/s, p = 0.01; − 0.71s, p = 0.026, respectively). Compared with Q1 of dietary intake, women in Q2 and Q5 had faster gait speed (+ 0.04m/s, p < 0.01 for both); women in Q4 and Q5 had faster chair-stand times (− 0.67s, p = 0.002; − 0.57s, p = 0.013, respectively). No associations were found for dietary vitamin C in men. These findings suggest that maintaining optimal plasma vitamin C status could be important for maintaining physical function. Longitudinal and intervention studies are needed to support our findings.