He Xingchen, Lin Yijia, Wu Xinyi, Li Min, Zhong Tianyu, Zhang Yanhong, Weng Xuliang
The Affiliated Guangzhou Hospital of TCM of Guangzhou University of Chinese Medicine, Guangzhou, China.
Sleep Research Institute of Traditional Chinese Medicine, Guangzhou Medical University, Guangzhou, China.
Front Nutr. 2025 Jun 4;12:1585863. doi: 10.3389/fnut.2025.1585863. eCollection 2025.
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.
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.
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; = 1.11, 95% CI: 0.37-1.85) and the Digit Symbol Substitution Test (DSST; = 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 pronounced among smokers (DSST: = 0.59 per 100 mg/day, = 0.0009), with no significant associations observed in non-smokers.
Vitamin C intake is associated with improved cognitive function in older U.S. adults, with distinct dose-dependent and domain-specific threshold effects. Smoking status significantly modifies this relationship, suggesting that personalized supplementation strategies targeting smokers may enhance cognitive protection.
研究美国老年人维生素C摄入量与认知功能之间的关联，重点关注剂量反应特征和关键亚组的效应修正。
利用2011 - 2014年美国国家健康与营养检查调查（NHANES）的数据，这项横断面研究纳入了2801名年龄≥60岁的成年人。通过标准化的24小时饮食回忆和补充剂问卷评估总维生素C摄入量。使用阿尔茨海默病注册协会（CERAD）单词学习测试、动物流畅性测试（AFT）和数字符号替换测试（DSST）评估认知功能。采用多变量调整线性回归模型、平滑曲线拟合和分层回归分析来检验关联和效应修正。
我们的分析揭示了维生素C摄入量与认知表现之间的非线性剂量反应关系。在完全调整模型中，与最低四分位数（Q1）的参与者相比，最高摄入量四分位数（Q4）的参与者在听觉流畅性测试（AFT；β = 1.11，95%CI：0.37 - 1.85）和数字符号替换测试（DSST；β = 3.35，95%CI：1.49 - 5.21）中表现明显更好。阈值分析表明，DSST的认知保护在摄入量为500毫克/天时达到峰值，而AFT的益处在120毫克/天时趋于平稳。分层分析进一步表明，维生素C对认知的益处在吸烟者中更为明显（DSST：每100毫克/天β = 0.59，P = 0.0009），在非吸烟者中未观察到显著关联。
在美国老年人中，维生素C摄入量与认知功能改善有关，具有明显的剂量依赖性和特定领域的阈值效应。吸烟状况显著改变了这种关系，表明针对吸烟者的个性化补充策略可能增强认知保护。
