Background: Oxidative stress is implicated in the pathogenesis of Alzheimer's disease (AD). Accumulating evidence shows that antioxidant-rich food reduces the risk of AD by inhibiting oxidative stress. This study investigates whether serum levels of carotenoids were associated with the risk of AD mortality in a nationally representative sample of US adults.
Methods: We used data from the Third Nutrition and Health Examination Survey (NHANES III) database and the NHANES III Linked Mortality File. A total of 6,958 participants aged older than 50 years were included in this study.
Results: We found that high serum levels of lycopene and lutein+zeaxanthin at baseline were associated with a lower risk of AD mortality after adjustment for potential covariates. The reduction in the mortality risk was progressively raised by increasing serum lycopene (HR = 0.26, 95% CI 0.10-0.69) and lutein+zeaxanthin (HR = 0.43, 95% CI 0.22-0.85) levels. In contrast, no associations with AD mortality were observed for other serum carotenoids, including alpha-carotene, beta-carotene, and beta-cryptoxanthin.
Conclusion: High serum levels of lycopene and lutein+zeaxanthin are associated with a lower risk of AD mortality in adults. Our findings suggest that a high intake of lycopene- or lutein+zeaxanthin-rich food may be important for reducing the AD mortality risk.