According to the latest research, lutein and zeaxanthin, two pigments commonly found in fruits, eggs and vegetables, especially spinach, kale and turnips, can play an important role in boosting cognitive skills.
When there is a strong presence of these pigments in the diet, they accumulate in the central retina, and function as a filter against the damaging blue components of light. The exposure to natural and artificial light, as well as the metabolic processes, produce free radicals. The free radicals damage cells through a process called oxidation. Their benefit against light-induced oxidative damage like cataracts for instance is well-documented and established. Women who consume more lutein experience less vision problems like blurriness, glare, and even cataracts.
Emerging research shows a connection between the concentration of lutein and cognitive performance in adults and children. A study conducted in 2013 discovered the correlation between the concentration of lutein in the retina, with its presence in the brain . The region of the brain where lutein accumulates is responsible for speech, vision, control cognition and hearing.
A study reported in the International Journal of Nutritional Neuroscience measured the level of lutein in the eyes of 49 school-age children. The ones with high level of lutein reported higher academic performances than those with a lower lutein concentration [2-4].
Another study conducted by the University of Georgia showed that adding lutein and zeaxanthin improved cognitive function in older women and men. The researchers randomly assigned 62 adults over age 60 into two groups. The first took a lutein and zeaxanthin supplement, and the control group took a placebo. Participants completed a number of cognitive tests to determine their brain function and repeated same number of tests every four months. After one year of supplementation with lutein and zeaxanthin, participants showed improved complex attention, executive function and mental flexibility.
These studies conducted on children and adults are not conclusive, and don’t intend to prove that the level of lutein is the cause of the cognitive performance. However, there is an indication that lutein may play an important role in cognition, and further studies will be required. In any case, for most people, increasing green vegetables in the diet can only be a good thing!
1. Vishwanathan R, Neuringer M, Snodderly DM, et al. (2013) Macular lutein and zeaxanthin are related to brain lutein and zeaxanthin in primates. Nutr Neurosci 16, 21–29.
2. Barnett, S.M.; Khan, N.A.; Walk, A.M.; Raine, L.B.; Moulton, C.; Cohen, N.J.; Kramer, A.F.; Hammond, B.R.; Renzi-Hammond, L.; Hillman, C.H. Macular pigment optical density is positively associated with academic performance among preadolescent children. Nutr. Neurosci. 2017, 8305, 1–9. [CrossRef] [PubMed] 3. Walk, A.M.; Khan, N.A.; Barnett, S.M.; Raine, L.B.; Kramer, A.F.; Cohen, N.J.; Moulton, C.J.; Renzi-Hammond, L.M.; Hammond, B.R.; Hillman, C.H. From neuro-pigments to neural efficiency: The relationship between retinal carotenoids and behavioral and neuroelectric indices of cognitive control in childhood. Int. J. Psychophysiol. 2017, 118, 1–8. [CrossRef] [PubMed] 4. Hassevoort, K.M.; Khazoum, S.E.; Walker, J.A.; Barnett, S.M.; Raine, L.B.; Hammond, B.R.;