The effects of lutein and zeaxanthin on resting state functional connectivity in older Caucasian adults: a randomized controlled trial
Brain Imaging and Behavior
Aging; Default mode network; Lutein; Nutrition; Resting state fMRI; Sparse representation
© 2019, Springer Science+Business Media, LLC, part of Springer Nature. 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.
Lindbergh, C., Lv, J., Zhao, Y., Mewborn, C., Puente, A., Terry, D., Renzi-Hammond, L., Hammond, B., Liu, T., & Miller, L. (2020). The effects of lutein and zeaxanthin on resting state functional connectivity in older Caucasian adults: a randomized controlled trial. Brain Imaging and Behavior, 14 (3). http://dx.doi.org/10.1007/s11682-018-00034-y