Study links lutein levels to higher IQ

Superior macula pigment optical density (MPOD) – a measure of lutein levels in the eye and brain – is associated with higher IQ levels, says a new study. Data from 114 overweight and obese people revealed that higher MPOD was an independent predictor of IQ and fluid intelligence, according to a new paper in Nutrients by scientists from the University of Illinois at Urbana-Champaign.

“We demonstrate these relationships among individuals with overweight and obesity, known to be at risk for lower MPOD status,” they wrote. “Given that excess fat mass has also been related to poorer cognitive function and brain health, the finding that MPOD was positively related to intelligence provides a potential opportunity to counter obesity-related cognitive impairment using dietary approaches.”

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)

“Although many studies in recent years have linked greater MPOD with multiple aspects of cognitive function, to our knowledge, this is the first study to examine the influence of both adiposity and macular xanthophylls and their implications for cognitive abilities among individuals with overweight and obesity,” wrote the authors of the new Nutrients paper.

“Further, the extent to which macular xanthophylls contribute to the intellectual abilities has not been directly investigated. Superior MPOD status in the current sample was related to higher general intelligence as indicated by IQ.”

Study details

Led by Naiman Khan, PhD, RD, the UIUC scientists assessed MPOD, dietary lutein and zeaxanthin intakes, and intelligence (using the Kaufman Brief Intelligence Test-2) in 114 overweight and obese people aged between 25 and 45.

The results showed that MPOD was inversely related to a person’s percentage fat, and it was also positively associated with IQ and fluid intelligence, which is our ability to problem solve in novel situations, and to think creatively and flexibly in response to everyday challenges. On the other hand, no significant associations were observed between MPOD and crystalized intelligence, which is the ability to retrieve and use information acquired throughout life.

“One of the novel implications of the present work is that it demonstrates that the positive implications of macular xanthophylls for intellectual abilities are evident even among adults with overweight and obesity or individuals with greater risk for suboptimal macular xanthophyll status,” wrote the researchers.

Source: Nutrients 2018, 10(4), 396; doi:10.3390/nu10040396
“Macular Xanthophylls Are Related to Intellectual Ability among Adults with Overweight and Obesity”
Authors: N.A. Khan, et al.