Dietary Antioxidants and Long-term Risk of Dementia

Abstract

Oxidative stress is thought to have an important role in the pathogenesis of Alzheimer disease (AD),^1,2 a disease that likely begins years, if not decades, before clinical onset of dementia. In line with this hypothesis, experimental data support the notion that antioxidants protect against neurodegeneration.^3-8 Although clinical trials have shown no benefit of antioxidant supplements for AD,^9,10 the wider variety of antioxidants in food sources is not well studied relative to dementia risk; a few studies,^11-14 with varying lengths of follow-up, have yielded inconsistent results. Results of the Rotterdam Study¹⁵ previously found that higher dietary intakes of vitamins E and C were related to lower risk of dementia and AD over 6 years of follow-up. Still, substantial evidence indicates that earlier exposures are important for predicting dementia risk in later life,¹⁶ and specific evidence indicates that antioxidants may affect early stages of dementia development.^17-19 Therefore, we evaluated the associations of dietary vitamin E, vitamin C, beta carotene, and flavonoid intake with long-term risk of dementia based on 10 years of follow-up, taking advantage of longer follow-up and substantially more dementia cases than were available in the 2002 Rotterdam Study.