Non-linear association between dietary fiber intake and cognitive function mediated by vitamin E: a cross-sectional study in older adults
BackgroundEmerging evidence suggests dietary fiber may prevent cognitive decline, but its dose-response relationship and underlying mechanisms remain unclear. This study investigates the non-linear association between dietary fiber intake and cognitive function in older adults and explores the media...
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Frontiers Media S.A.
2025-07-01
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| Series: | Frontiers in Nutrition |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/fnut.2025.1611162/full |
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| author | Qianyi He Lucy An Yue Yue Can Cui Chongjian Wang Hong Xu Yunfei Guo Xinyu Zhao |
| author_facet | Qianyi He Lucy An Yue Yue Can Cui Chongjian Wang Hong Xu Yunfei Guo Xinyu Zhao |
| author_sort | Qianyi He |
| collection | DOAJ |
| description | BackgroundEmerging evidence suggests dietary fiber may prevent cognitive decline, but its dose-response relationship and underlying mechanisms remain unclear. This study investigates the non-linear association between dietary fiber intake and cognitive function in older adults and explores the mediating role of vitamin E.MethodsThis cross-sectional analysis of nationally representative National Health and Nutrition Examination Survey (NHANES) Data from 2011 to 2014 included 2,713 adults aged ≥60 years. Dietary fiber intake was assessed using two 24-h dietary recalls. Cognitive function was evaluated using a comprehensive battery comprising three standardized assessments: the Digit Symbol Substitution Test (DSST) to measure processing speed, the Animal Fluency Test (AFT) to assess executive function, and a Consortium to Establish a Registry for Alzheimer's Disease (CERAD) subtest to evaluate memory performance. Composite z-scores were calculated for each individual test and combined to generate a global cognition composite score. Generalized additive models (GAM) were applied to model non-linear relationships, and threshold effects were evaluated using two-piece-wise linear regression. Mediation analysis quantified the mediating role of vitamin E in the dietary fiber-cognitive function association, with effects assessed via the non-parametric percentile bootstrap method. Subgroup-specific sensitivity analyses demonstrated consistent findings.ResultsA J-shaped relationship between cognitive function and dietary fiber intake was identified using a two-piece-wise linear regression model. DSST scores reached a plateau at 29.65 g/day of fiber intake (likelihood ratio test P < 0.001), while composite z-scores reached a plateau at 22.65 g/day (likelihood ratio test P = 0.018). Below the inflection point, dietary fiber intake demonstrated a positive association with DSST scores (β: 0.18, 95% CI: 0.01–0.26, P < 0.0001), whereas above this threshold, the relationship became negative (β: −0.15, 95% CI: −0.29 to −0.02, P = 0.0265). Similarly, for composite z-scores, a positive association was observed below the inflection point (β: 0.01, 95% CI: 0.00–0.01, P = 0.0004), while the relationship appeared to saturate above this threshold (β: −0.00, 95% CI: −0.01–0.00, P = 0.9043). Mediation analysis revealed that vitamin E intake significantly mediated 85.0% (P < 0.0001) of the association between dietary fiber intake and composite z-scores, and 86.8% (P < 0.0001) of the association between dietary fiber intake and DSST scores.ConclusionModerate dietary fiber intake is associated with optimal cognitive performance, largely mediated by vitamin E. |
| format | Article |
| id | doaj-art-d0892d576f4940b0bac9f225c4c4744d |
| institution | Matheson Library |
| issn | 2296-861X |
| language | English |
| publishDate | 2025-07-01 |
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| spelling | doaj-art-d0892d576f4940b0bac9f225c4c4744d2025-07-02T04:14:23ZengFrontiers Media S.A.Frontiers in Nutrition2296-861X2025-07-011210.3389/fnut.2025.16111621611162Non-linear association between dietary fiber intake and cognitive function mediated by vitamin E: a cross-sectional study in older adultsQianyi He0Lucy An1Yue Yue2Can Cui3Chongjian Wang4Hong Xu5Yunfei Guo6Xinyu Zhao7Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, ChinaFaculty of Medicine and Health Sciences, McGill University, Montreal, QC, CanadaDepartment of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, ChinaDepartment of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, ChinaDepartment of Epidemiology and Biostatistics, College of Public Health, Zhengzhou University, Zhengzhou, Henan, ChinaSchool of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, ChinaSchool of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, ChinaDepartment of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, ChinaBackgroundEmerging evidence suggests dietary fiber may prevent cognitive decline, but its dose-response relationship and underlying mechanisms remain unclear. This study investigates the non-linear association between dietary fiber intake and cognitive function in older adults and explores the mediating role of vitamin E.MethodsThis cross-sectional analysis of nationally representative National Health and Nutrition Examination Survey (NHANES) Data from 2011 to 2014 included 2,713 adults aged ≥60 years. Dietary fiber intake was assessed using two 24-h dietary recalls. Cognitive function was evaluated using a comprehensive battery comprising three standardized assessments: the Digit Symbol Substitution Test (DSST) to measure processing speed, the Animal Fluency Test (AFT) to assess executive function, and a Consortium to Establish a Registry for Alzheimer's Disease (CERAD) subtest to evaluate memory performance. Composite z-scores were calculated for each individual test and combined to generate a global cognition composite score. Generalized additive models (GAM) were applied to model non-linear relationships, and threshold effects were evaluated using two-piece-wise linear regression. Mediation analysis quantified the mediating role of vitamin E in the dietary fiber-cognitive function association, with effects assessed via the non-parametric percentile bootstrap method. Subgroup-specific sensitivity analyses demonstrated consistent findings.ResultsA J-shaped relationship between cognitive function and dietary fiber intake was identified using a two-piece-wise linear regression model. DSST scores reached a plateau at 29.65 g/day of fiber intake (likelihood ratio test P < 0.001), while composite z-scores reached a plateau at 22.65 g/day (likelihood ratio test P = 0.018). Below the inflection point, dietary fiber intake demonstrated a positive association with DSST scores (β: 0.18, 95% CI: 0.01–0.26, P < 0.0001), whereas above this threshold, the relationship became negative (β: −0.15, 95% CI: −0.29 to −0.02, P = 0.0265). Similarly, for composite z-scores, a positive association was observed below the inflection point (β: 0.01, 95% CI: 0.00–0.01, P = 0.0004), while the relationship appeared to saturate above this threshold (β: −0.00, 95% CI: −0.01–0.00, P = 0.9043). Mediation analysis revealed that vitamin E intake significantly mediated 85.0% (P < 0.0001) of the association between dietary fiber intake and composite z-scores, and 86.8% (P < 0.0001) of the association between dietary fiber intake and DSST scores.ConclusionModerate dietary fiber intake is associated with optimal cognitive performance, largely mediated by vitamin E.https://www.frontiersin.org/articles/10.3389/fnut.2025.1611162/fulldietary fibervitamin Ecognitive functionthreshold effectmediation analysis |
| spellingShingle | Qianyi He Lucy An Yue Yue Can Cui Chongjian Wang Hong Xu Yunfei Guo Xinyu Zhao Non-linear association between dietary fiber intake and cognitive function mediated by vitamin E: a cross-sectional study in older adults Frontiers in Nutrition dietary fiber vitamin E cognitive function threshold effect mediation analysis |
| title | Non-linear association between dietary fiber intake and cognitive function mediated by vitamin E: a cross-sectional study in older adults |
| title_full | Non-linear association between dietary fiber intake and cognitive function mediated by vitamin E: a cross-sectional study in older adults |
| title_fullStr | Non-linear association between dietary fiber intake and cognitive function mediated by vitamin E: a cross-sectional study in older adults |
| title_full_unstemmed | Non-linear association between dietary fiber intake and cognitive function mediated by vitamin E: a cross-sectional study in older adults |
| title_short | Non-linear association between dietary fiber intake and cognitive function mediated by vitamin E: a cross-sectional study in older adults |
| title_sort | non linear association between dietary fiber intake and cognitive function mediated by vitamin e a cross sectional study in older adults |
| topic | dietary fiber vitamin E cognitive function threshold effect mediation analysis |
| url | https://www.frontiersin.org/articles/10.3389/fnut.2025.1611162/full |
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