Serum Lycopene, Lutein and Zeaxanthin, and the Risk of Alzheimer's Disease Mortality in Older Adults

Abstract

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.

The Impact of Supplemental Macular Carotenoids in Alzheimer's Disease: A Randomized Clinical Trial

“…It is known that patients with dementia and AD have poor diets lacking in fruit and vegetables [47][48][49] and therefore we know that, on average, patients with AD consume less carotenoids than patients free of AD. Furthermore, it has been shown that high serum concentrations of L+Z are associated with a lower risk of AD mortality in adults [50] and that plasma antioxidants are depleted in mild cognitive impairment and in AD when compared to subjects with normal cognitive function [51]. Indeed, our data is consistent with the above studies, as we confirm that (at baseline) patients with AD have significantly lower (33% lower) dietary intake of foods known to contain the carotenoids (L and Z) when compared to control subjects of comparable age.…”

Potential Protective Role of Thymoquinone on Experimentally-induced Alzheimer Rats

“…Previous studies on the chronological events of AD showed the oxidative stress to be the earliest event in AD preceding Aβ aggregation. This oxidative stress is correlated to the incidence [36], duration [37], severity [35] and the mortality rate [38] of AD. Moreover, the oxidative stress is accused of direct neuronal apoptosis [39], enhancement of Aβ aggregation as well as tau phosphorylation [37,40].…”

Nutritional and Pharmacological Strategies to Regulate Microglial Polarization in Cognitive Aging and Alzheimer’s Disease

“…However, no in vivo data on the anti-inflammatory effect of lutein are currently available. Interestingly, a human study involving nearly 7000 participants aged 50 or older found an association between high levels of serum lycopene and lutein and a lower risk of mortality by AD (Min and Min, 2014). Current research on AD and bioactive compounds has also focused on less-known carotenoinds.…”