Data published in the journal Physiology & Behavior indicated that supplementation with these macular xanthophylls led to increases in both macula pigment optical density (MPOD) – a measure of lutein levels in the eye and brain – and brain-derived neurotrophic factor (BDNF), which has been described as an important neurotrophic factor participating in memory and learning.
And these, along with blood lutein and/or zeaxanthin levels, were associated with improvements in composite and verbal memory, psychomotor and processing speed, or sustained attention, reported the scientists from the University of Georgia (Athens, GA) and the Duke Eye Center (Durham, NC).
“Given that cognition is a collection of several different abilities, these differences lend insight into the neural and biochemical mechanisms underlying different parameters of cognitive performance,” they wrote. “The connection between the nervous system, the immune system, cognitive performance, and diet represents an exciting new area of research.”
The study used OmniActive Health Technologies’ Lutemax 2020 and the company funded the study.
Lutein and brain health
The link between lutein and eye health was first reported in 1994 by Dr Johanna Seddon and her co-workers at Harvard University, who found a link between the intake of carotenoid-rich food, particularly dark green leafy vegetables like spinach, and a significant reduction in age-related macular degeneration (AMD) (JAMA, Vol. 272, pp. 1413-1420).
Numerous studies with data from primates, children, middle-aged people, and the elderly now support the importance of lutein in brain health, which is unsurprising given that the eyes and the brain are connected.
Indeed, recent findings from pediatric brain tissue studies have shown that about 60% of the total carotenoids in the pediatric brain tissue is lutein, and yet NHANES data show that lutein is only about 12% of the carotenoids in the diets, so there is a preference for lutein in the brain (Vishwanathan et al. J Pediatr Gastroenterol Nutr. 2014).
A 2017 study by scientists from Queens University Belfast and the Macular Pigment Research Group at the Waterford Institute of Technology found that higher blood levels of lutein and zeaxanthin may be associated with better cognition, memory, and executive function (Journal of Gerontology, Series A).
Nicole Stringham, Philip Holmes, and James Stringham recruited 59 young healthy people to participate in their 6-month, double-blind, placebo-controlled trial. Participants were randomly assigned to receive either placebo, or macular xanthophyll supplements at doses of 13 mg or 27 mg per day. The lower dose supplement contained 10.86 mg of lutein and 2.27 mg of zeaxanthin plus meso-zeaxanthin, while the higher dose supplement contained 22.33 mg of lutein and 4.70 mg of zeaxanthin plus meso-zeaxanthin.
Results showed that both xanthophyll groups experienced significant increases in BDNF, MPOD, and anti-oxidant capacity, compared with placebo. In addition, serum levels of the macular xanthophyll increased.
The increase in BDNF was related to MPOD and to significant decreases in levels of the pro-inflammatory cytokine and IL-1beta.
“The significant relationship between change in BDNF and IL-1β over the course of the study suggests that regular consumption of [macular xanthophylls] interrupts the inflammatory cascade that can lead to reduction of BDNF,” wrote the researchers.
When the researchers looked at cognitive measures, they found that both lutein + zeaxanthin groups displayed improvements in scores for composite memory, verbal memory, sustained attention, psychomotor speed, and processing speed, but were unchanged in the placebo group.
Digging deeper into the data, they found that changes in BDNF were linked to changes in composite and verbal memory, while MPOD changes were related to changes in psychomotor and processing speed.
Serum lutein changes were related to verbal and composite memory, and sustained attention, whereas changes in serum zeaxanthin isomers linked to verbal memory.
“Given that cognition is a collection of several different abilities, these differences lend insight into the neural and biochemical mechanisms underlying different parameters of cognitive performance,” wrote the researchers.
“The connection between the nervous system, the immune system, cognitive performance, and diet represents an exciting new area of research.
“Planned future studies include further evaluation of the relationship between diet and neuroplasticity, determination of the effects of nutritional intervention with carotenoids in early childhood on the developing brain, and investigation of potential effects of [macular xanthophyll] supplementation in diabetes.”
Source: Physiology & Behavior
Published online ahead of print, doi: 10.1016/j.physbeh.2019.112650
“Effects of macular xanthophyll supplementation on brain-derived neurotrophic factor, pro-inflammatory cytokines, and cognitive performance”
Authors: N.T. Stringham et al.