The effects of lutein and zeaxanthin on resting state functional connectivity in older Caucasian adults: a randomized controlled trial

• Published in: Brain imaging and behavior 2020-06, Vol.14 (3), p.668-681
• Main Authors: Lindbergh, Cutter A., Lv, Jinglei, Zhao, Yu, Mewborn, Catherine M., Puente, Antonio N., Terry, Douglas P., Renzi-Hammond, Lisa M., Hammond, Billy R., Liu, Tianming, Miller, L. Stephen
• Format: Article
• Language: English
• Subjects: Adolescent; Adults; Aged; Aging; Biomedical and Life Sciences; Biomedicine; Brain; Brain - diagnostic imaging; Brain mapping; Carotenoids; Clinical trials; Coding; Cognitive ability; Computational neuroscience; Data acquisition; Functional magnetic resonance imaging; Humans; Integrity; Learning algorithms; Life span; Lutein; Machine learning; Magnetic Resonance Imaging; Nervous system; Networks; Neural networks; Neuroimaging; Neuropsychology; Neuroradiology; Neurosciences; Older people; Original Research; Psychiatry; Randomization; Retina; Supplements; Youth; Zeaxanthin; Zeaxanthins
• ISSN: 1931-7557; 1931-7565
• DOI: 10.1007/s11682-018-00034-y

The carotenoids lutein (L) and zeaxanthin (Z) accumulate in retinal regions of the eye and have long been shown to benefit visual health. A growing literature suggests cognitive benefits as well, particularly in older adults. The present randomized controlled trial sought to investigate the effects of L and Z on brain function using resting state functional magnetic resonance imaging (fMRI). It was hypothesized that L and Z supplementation would (1) improve intra -network integrity of default mode network (DMN) and (2) reduce inter -network connectivity between DMN and other resting state networks. 48 community-dwelling older adults (mean age = 72 years) were randomly assigned to receive a daily L (10 mg) and Z (2 mg) supplement or a placebo for 1 year. Resting state fMRI data were acquired at baseline and post-intervention. A dictionary learning and sparse coding computational framework, based on machine learning principles, was used to investigate intervention-related changes in functional connectivity. DMN integrity was evaluated by calculating spatial overlap rate with a well-established DMN template provided in the neuroscience literature. Inter -network connectivity was evaluated via time series correlations between DMN and nine other resting state networks. Contrary to expectation, results indicated that L and Z significantly increased rather than decreased inter -network connectivity (Cohen’s d  = 0.89). A significant intra -network effect on DMN integrity was not observed. Rather than restoring what has been described in the available literature as a “youth-like” pattern of intrinsic brain activity, L and Z may facilitate the aging brain’s capacity for compensation by enhancing integration between networks that tend to be functionally segregated earlier in the lifespan.