Recent research bolsters case for lutein's cognitive effects

Lutein is well-established as an eye health ingredient, given that it and zeaxanthin are concentrated in the macula.  

The macula is a yellow spot of about five millimeters diameter on the retina (lutein and zeaxanthin are the source of the yellow color). As we age, levels of the pigments in the macula decrease naturally, thereby increasing the risk of age-related macular degeneration (AMD).

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​​). The researchers analyzed data from 4,076 community-dwelling Irish adults aged 50 or older.

Much of the research has been led by Elizabeth Johnson, PhD, Scientist I in the Antioxidants Laboratory in the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Prof John Nolan and Prof Stephen Beatty from the Macular Pigment Research Group at the Waterford Institute of Technology in Ireland, and Billy Hammond, PhD, from the Behavioral and Brain Sciences Program, Department of Psychology at the University of Georgia.

New findings​

A recent paper published in The Journal of Nutrition​, co-authored by Dr Johnson, reported that higher maternal intakes of lutein and zeaxanthin during pregnancy were associated with better verbal intelligence and behavior regulation ability in mid-childhood for the children.

The study was said to be the first to evaluate how maternal lutein and zeaxanthin intakes during pregnancy may impact cognition, behavior, and social-emotional development in the children.

Analysis of data from 1,580 mother-child pairs participating in a study called Project Viva revealed that increased maternal lutein and zeaxanthin intakes during pregnancy were associated with some improved cognitive measures for in mid-childhood, but such improvements were not observed in early childhood.

“This suggests that the benefits of higher L/Z exposure in utero may be manifested later in childhood perhaps as a consequence of long-term programming of cognition by prenatal carotenoid exposure,” ​wrote the researchers.

Moving through to healthy middle-aged adults, results of an observational study published online in January 2021 in Nutritional Neuroscience​ examined the impact of lutein, zeaxanthin, and choline on cognitive function in middle-aged adults with overweight and obesity.

The results showed that higher intakes of choline and lutein plus zeaxanthin were associated with faster performance on a cognitive flexibility task.

“Increased consumption of both of these dietary components may be beneficial for cognitive processing among individuals with overweight and obesity, who may be at a higher risk for cognitive decline in later life,” ​wrote the researchers, led by Caitlyn Edwards from University of Illinois at Urbana-Champaign.

“Future studies should therefore investigate the potential interactive properties of dietary components such as lutein and choline to inform dietary recommendations for cognitive and brain health.”​

Building on a scientific foundation​

Data from intervention studies support the correlations reported in this new study. For example, Prof Nolan and his group in Ireland reported in 2018 that 12 months of supplementation with the macular carotenoids lutein, zeaxanthin, and meso-zeaxanthin in men and women with low macular pigment levels led to exhibited “statistically significant improvements in memory when compared to the placebo group”​.  (J Alzheimers Dis​​, 2018, Vol. 61, Issue 3, pp. 947-961)

“These findings are in keeping with emerging and previous research, which has consistently shown a positive relationship between measures of [macular pigment] and cognitive function,” ​they wrote.

“Given that [macular pigment] levels correlate with [lutein and zeaxanthin] concentrations in brain tissue, and that concentrations of these carotenoids relate positively to cognitive function, it is reasonable to hypothesize that these compounds assist in optimizing the neurocognitive environment. The implications of these findings for cognition in health and disease warrants further exploration.”​

Sources:
The Journal of Nutrition​
2021, Volume 151, Issue 3, Pages 615–627, doi: 10.1093/jn/nxaa348​
“Maternal Intake of Lutein and Zeaxanthin during Pregnancy Is Positively Associated with Offspring Verbal Intelligence and Behavior Regulation in Mid-Childhood in the Project Viva Cohort”​
Authors: H.A. Mahmassani, et al.

Nutritional Neuroscience​
2021, Published online ahead of print, doi: 10.1080/1028415X.2020.1866867​
“Dietary lutein plus zeaxanthin and choline intake is interactively associated with cognitive flexibility in middle-adulthood in adults with overweight and obesity”​
Authors: C.G. Edwards, et al.