Plasma Lutein and Zeaxanthin Linked to Improved Cognitive Function in Older Adults

by | Oct 9, 2017 | 2017, Brain Health, Carotenoids, Cognitive Health, Lutein, Zeaxanthin

Written by Angeline A. De Leon, Staff Writer. Analysis of 4,076 community-dwelling adults found that higher plasma lutein and zeaxanthin were independently associated with better composite scores for global cognition, memory, and executive function; however, only zeaxanthin, was associated with better processing speed.

agingCarotenoids are lipid soluble pigments ubiquitously found in fruits and vegetables. While the antioxidant properties of carotenoids in general are recognized for their vital benefits for overall health 1, in terms of brain and cognitive function, two particular carotenoids, lutein and zeaxanthin, play the most critical role. As the primary components of macular pigment (a protective substance in the eye) 2, both carotenoids function to protect the retina of the eye from light-induced damage by stabilizing reactive oxygen species 3,4. Higher levels of macular pigment, a product of increased intake of lutein and zeaxanthin, have been linked to improved cognitive function in older adults across various domains 5. In fact, of all carotenoids, lutein and zeaxanthin are the most predominantly found in the human brain 6, with increased concentrations associated with enhanced cognitive performance 7. Research underscores the natural connection between the eye and brain, showing that circulating levels of lutein and zeaxanthin can influence the functional processes of both systems. In a study conducted by the Waterford Institute of Technology in Ireland, investigators sought to ascertain whether higher concentrations of the carotenoids may directly protect against cognitive decline in older adults in the same they have been shown to inhibit age-related macular degeneration 8.

A total of 4,076 community-dwelling adults (aged 50 years and older) were involved in the cross-sectional, population-based, prospective cohort study conducted as part of The Irish Longitudinal Study on Aging. Cognitive function was evaluated using a battery of neuropsychological tests designed to tap into memory, processing speed, executive function and global cognition. Plasma levels of total lutein and zeaxanthin were analyzed based on non-fasting venous blood samples provided by participants.

Quantitative analysis of the data revealed a significant, positive, independent association for both lutein and zeaxanthin and the following:

  • Global cognition (lutein: β = 0.048, 95% confidence interval [CI] 0.021 to 0.075, p < 0.001; zeaxanthin: β = 0.112, 95% CI 0.039 to 0.185, p = 0.003),
  • Memory (lutein: β = 0.033, 95% CI 0.004 to 0.061, p = 0.026; zeaxanthin: β = 0.081, 95% CI 0.004 to 0.157, p = 0.039)
  • Executive function (lutein: β = 0.040, 95% CI 0.013 to 0.068, p = 0.004; zeaxanthin: β = 0.120, 95% CI 0.043 to 0.197, p = 0.002).
  • Higher plasma zeaxanthin, but not lutein, was also related to better processing speed (β = 0.130, 95% CI 0.052 to 0.208, p = 0.001).

General findings support a meaningful and independent relationship between plasma concentrations of lutein and zeaxanthin and cognitive performance across multiple domains. Evidence suggests that carotenoid concentrations in the body may offer certain neuroprotective properties, highlighting the key role of nutrition in the face of cognitive aging and age-related diseases. Because of the cross-sectional nature of the current study’s design, prospective research in the form of randomized clinical trials is still needed to validate the cognitive benefits of lutein and zeaxanthin in the elderly.

Source: Feeney, Joanne, Neil O’Leary, Rachel Moran, Aisling M. O’Halloran, John M. Nolan, Stephen Beatty, Ian S. Young, and Rose Anne Kenny. “Plasma Lutein and Zeaxanthin Are Associated With Better Cognitive Function Across Multiple Domains in a Large Population-Based Sample of Older Adults: Findings from The Irish Longitudinal Study on Aging.” Journals of Gerontology Series A: Biomedical Sciences and Medical Sciences (2017): glw330.

© The Author 2017. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved.

Posted October 9, 2017.

Angeline A. De Leon, MA, graduated from the University of Illinois at Urbana-Champaign in 2010, completing a bachelor’s degree in psychology, with a concentration in neuroscience. She received her master’s degree from The Ohio State University in 2013, where she studied clinical neuroscience within an integrative health program. Her specialized area of research involves the complementary use of neuroimaging and neuropsychology-based methodologies to examine how lifestyle factors, such as physical activity and meditation, can influence brain plasticity and enhance overall connectivity.

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