By Caleb Sooknanan ’20
Lutein — a carotenoid or pigment from green foods such as spinach and kiwifruit — can be quantified in central nervous system tissue, making it a useful way of evaluating diet’s effect on the brain. However, scientists are still determining whether higher lutein amounts yield cognitive ability improvements. Doctor Naiman A. Khan and researchers at the University of Illinois at Urbana-Champaign conducted a study to determine relationships between age and retinal lutein levels in adults.
The researchers collected data from 60 adults —ranging in age from 25 to 45 years old — from the Eastern-Central Illinois region. A macular pigment optical density (MPOD) test determined the lutein amount in each subject’s eyes by prompting the subject to look into a scope, observe a flickering light, and indicate when the light was no longer visible. Electrodes were then placed on each adult’s scalp to measure neural conditions during three cognitive tasks. The researchers first had participants view a series of circles and respond to large circle appearances. Participants were then asked to view an arrangement of arrows, focus on a centralized target arrow, and quickly indicate its direction. For the final task, participants responded to “go” stimuli or small circles while dismissing “no-go” stimuli or large circles.
Higher lutein amount advantages were evident from the second test’s results, as participants closer to the age of 25 were able to more quickly and effectively perform the associated task. The researchers also found that participants with higher MPOD scores were more likely to perform the task at consistent speeds when the non-centered arrows were faced in the opposite direction of the target arrow.
The researchers suggested that adult age and MPOD have selective benefits on cognitive ability, but the study itself was limited as a cross-sectional investigation, so it could not directly answer questions regarding the origins of the participants’ neural changes. Nevertheless, the study’s outcome suggests that retinal carotenoids present health benefits in adults. Further research should determine how carotenoids affect cognitive ability throughout a human’s full lifespan.
- N. Khan, et al., The role of retinal carotenoids and age on neuroelectric indices of attentional control among early to middle-aged adults. Frontiers in Aging Neuroscience 9, (2017). doi: 10.3389/fnagi.2017.00183
- Image retrieved from: http://i.ndtvimg.com/i/2015-10/kiwi-fruit_625x350_81445871711.jpg