Lutein and Zeaxanthin Improve Cognitive Function in Healthy Young Adults

by | Aug 19, 2019 | 2017, Brain Health, Lutein, Zeaxanthin

Written by Angeline A. De Leon, Staff Writer. One year of nutritional supplementation with 10 mg of lutein and 2 mg of zeaxanthin significantly increased their levels in the central nervous systems of healthy well-nourished college students and improved their cognitive functioning.

A wealth of studies looking at the relationship between nutrition and brain function have established the role of dietary intake on cellular metabolism 1, neuronal structure 2, and oxidative stress levels in the brain 3. Deficiency in micronutrients, for example, is linked to cognitive decline, dementia, and other types of neurodegenerative diseases, especially in the older adult population 4. Research on the effects of dietary carotenoids lutein (L), zeaxanthin (Z), and meso-zeaxanthin (MZ) on the brain function of young adults, however, is still relatively lacking 5. L + Z make up the macular pigment (MP) which is found in the center of the retina of the eye, and their concentration in neural tissue has been linked to visual and cognitive function in participants across different age groups 6,7. Research suggests that by increasing L + Z levels in the retina through supplementation, aspects of cognitive performance, such as spatial working memory, are also improved 8. This is thought to be true for older adults, in whom L + Z supplementation has been shown to lead to enhanced cognitive function 9,10. In order to verify whether carotenoid supplementation could also benefit younger subjects who are likely already at the height of their cognitive ability, researchers at the University of Georgia (2017) 11 examined the effects of L + Z supplementation on the cognitive performance of healthy young adults.

Using a randomized, double-blind, placebo-controlled study design, a total of 51 healthy young adults (mean age = 21.21 +/- 2.52 years) were recruited. 37 participants were assigned to receive an active supplement containing 10 mg L + 2 mg Z, and 14 participants were assigned to receive an identical placebo, with both groups instructed to take one tablet daily with their highest fat meal for 12 months. At baseline, Month 4, Month 8, and Month 12, retinal L + Z levels (macular pigment optical density, MPOD) were measured using customized heterochromatic flicker photometry, and serum L + Z levels were measured using high performance liquid chromatography to confirm participant compliance. Cognitive function was also assessed using a computerized test battery designed to evaluate domains such as verbal memory, visual memory, psychomotor speed, and cognitive flexibility.

After one year, subjects receiving L + Z supplementation showed significantly increased mean retinal L + Z levels (from 0.47 ng/µL +/- 0.18 to 0.56 ng/µL +/- 0.16, p < 0.001), whereas the placebo group showed no such significant increase (from 0.40 ng/µL +/- 0.12 to 0.44 ng/µL +/- 0.18, p > 0.05). At the end of the year, serum L, Z, and L + Z levels were also all significantly higher in the L + Z group vs. placebo (p = 0.029, p = 0.011, p = 0.023, respectively). Moreover, the active supplementation group was seen to score significantly higher than placebo on visual memory tasks (p < 0.04), and participants who had numerical increases of 0.10 or greater for MPOD (regardless of group assignment) scored significantly higher on complex attention (p < 0.04) and reasoning ability (p < 0.05) tasks, compared to subjects who did not experience a minimum increase of 0.10 in MPOD scores.

Overall results suggest that supplementation with L + Z over the course of one year produces significant increases in serum levels of L + Z in the central nervous systems of healthy young adults, along with subsequent improvement in cognitive performance. Elevated levels of L + Z (MPOD) were found to be linked to better performance on several areas of cognitive function, including complex attention and reasoning ability, but most significantly for visual memory. Thus, researchers confirm that the cognitive benefits of L + Z supplementation are not only evident for older adults, but for younger adults as well. It would be valuable for future studies to examine the specific structural and functional brain changes associated with L + Z supplementation using neuroimaging techniques. It is worth noting that the relatively high level of participants’ cognitive performance and nutritional status at baseline may limit the generalizability of present findings.

Source: Renzi-Hammond LM, Bovier ER, Fletcher LM, et al. Effects of a lutein and zeaxanthin intervention on cognitive function: a randomized, double-masked, placebo-controlled trial of younger healthy adults. Nutrients. 2017; 9: 1246. DOI: 10.3390/nu9111246.

© 2017 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).

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Posted August 19, 2019.

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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