Vitamin C intake and cognitive function in older U.S. adults: nonlinear dose–response associations and effect modification by smoking status

作者：Xingchen He, Yi‐Jia Lin, Xinyi Wu, Min� Li, Tianyu Zhong, Yanhong Zhang, Xuchu Weng · 发表于：Frontiers in Nutrition · 年份：2025 · DOI：10.3389/fnut.2025.1585863 · 被引用次数：2 · 研究领域：Vitamin C and Antioxidants Research、Antioxidant Activity and Oxidative Stress、Nutritional Studies and Diet

Objective To investigate the association between vitamin C intake and cognitive function in U.S. older adults, focusing on dose–response characteristics and effect modification of key subgroups. Methods Utilizing data from the 2011–2014 National Health and Nutrition Examination Survey (NHANES), this cross-sectional study included 2,801 adults aged ≥ 60 years. Total vitamin C intake was assessed via standardized 24-h dietary recalls and supplement questionnaires. Cognitive function was evaluated using the Consortium to Establish a Registry for Alzheimer’s Disease (CERAD) Word Learning Test, Animal Fluency Test (AFT), and Digit Symbol Substitution Test (DSST). Multivariate adjusted linear regression models, smooth curve fitting, and stratified regression analyses were employed to examine associations and effect modification. Results Our analysis revealed a nonlinear dose–response relationship between vitamin C intake and cognitive performance. In fully adjusted models, participants in the highest intake quartile (Q4) showed significantly better performance on the Auditory Fluency Test (AFT; β = 1.11, 95% CI: 0.37–1.85) and the Digit Symbol Substitution Test (DSST; β = 3.35, 95% CI: 1.49–5.21) compared to those in the lowest quartile (Q1). Threshold analyses indicated that cognitive protection for DSST peaked at an intake of 500 mg/day, while AFT benefits plateaued at 120 mg/day. Stratified analyses further demonstrated that the cognitive benefits of vitamin C were more pronounc...