Carotenoids Are Associated with Cognitive and Physical Performance in Individuals with Mild Cognitive Impairment

Written by Angeline A. De Leon, Staff Writer. Plasma levels of carotenoids lutein, zeaxanthin, β-cryptoxanthin, and β-carotene and y-tocopherol are significantly associated with measures of cognitive and physical fitness in the participating fifty-six individuals with mild cognitive impairment.

Cognitive impairment represents one of the most prominent medical challenges today, especially in the aging population and those with mild cognitive impairment (MCI) ¹. Over the years, a variety of lifestyle-based interventions, involving physical activity, nutrition, and cognitive training, have been posited as potential strategies for protecting against cognitive decline ². The basis for such lifestyle programs is predicated on studies suggesting that oxidative stress is linked to the progression of cognitive impairment ³ and may be reduced though exercise and nutrition ⁴. Consistent with this, initial research shows that there is a general link between cognitive impairment and certain nutrition biomarkers representative of antioxidant micronutrient protection against oxidative stress ⁵. A greater understanding is needed, however, to clarify the nature of the relationship between nutrition- and antioxidant defense-related biomarkers and cognitive health, especially in those facing cognitive impairment. Thus, researchers in Cologne, Germany (2019) investigated the relationship between nutrition biomarkers (carotenoid and tocopherols) and cognitive, as well as physical, performance in a group of subjects with MCI ⁶.

A total of 56 individuals with MCI (mean age = 73.1 +/- 5.8 years) participating in a NeuroExercise Study program (involving aerobic exercise, stretching and toning, or no physical activity prescription) were enrolled in the cross-sectional study. Participants underwent a full neuropsychological battery (assessing global cognitive function, verbal memory, psychomotor function, attention, verbal fluency, etc.) and a series of physical fitness tests (measuring physical activity level and mobility). Researchers also recorded fruit and vegetable intake using a food-frequency questionnaire and collected blood samples to determine concentration levels of carotenoids (lutein, zeaxanthin, β-cryptoxanthin, lycopene, α-carotene, and β-carotene), as well as retinol (vitamin A), α-tocopherol, and γ-tocopherol (vitamin E).

Analysis of the data revealed significant correlations between plasma levels of β-cryptoxanthin and the Timed Up and Go Test (physical fitness test measuring mobility, balance, and walking ability) (p < 0.05), as well as plasma levels of γ-tocopherol and the number of daily steps (p < 0.01). In addition, scores on the computerized CogState International Shopping List subtest (word list learning test for verbal memory) were found to be significantly correlated to plasma levels of four out of the six measured carotenoids, lutein, zeaxanthin, β-cryptoxanthin, and β-carotene (p < 0.01). A subgroup analysis of individuals displaying micronutrient levels above the median value vs. those displaying values below showed that the group with higher micronutrient levels performed significantly better than the latter group on physical (TUG: 8.0 +/- 0.9 s vs. 9.2 +/- 1.4 s, p = 0.002) as well as cognitive (card learning subtest of CogState: 58.6 +/- 8.3 vs. 65.7 +/- 8.4, p = 0.04) tests.

Evidence from the study suggests that lipophilic antioxidant micronutrients, namely carotenoids, are significantly associated with measures of cognitive and physical fitness, independent of fruit and vegetable intake, in individuals with MCI. Results are in line with previous research highlighting the link between plasma concentrations of micronutrients and higher-level cortical functions ⁷, and it is suggested, based on the correlation between β-cryptoxanthin levels and TUG, that carotenoids may also serve as a biomarker of physical frailty. Given the cross-sectional nature of the current study, it would be valuable to replicate findings using a randomized, double-blind, placebo-controlled study design. While the present study is also limited by a relatively small sample size, its employment of a highly comprehensive computerized neuropsychological battery is a notable strength.

Source: Gerger P, Pai R, Stuckenschneider, et al. Associations of lipophilic micronutrients with physical and cognitive fitness in persons with mild cognitive impairment. Nutrients. 2019; 11: 902. DOI: 10.3390/nu11040902.

© 2019 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 May 30, 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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