Athletes are familiar with hand-eye coordination, but what about eye-brain coordination? How these two organs communicate with each other is crucial to processing visual information quickly and accurately in order to catch a pass, block a shot or avoid a hazard.
Researchers from University of Georgia's Vision Sciences Laboratory have shed new light on how to improve visual processing speed.
A part of the retina called the macula contains a pigment comprised of the carotenoid xanthophylls lutein, zeaxanthin and meso-zeaxanthin. Macular pigment optical density (MPOD) affects temporal contrast sensitivity function (tCSF), a fancy term for the way scientists measure visual processing speed. The researchers looked at whether taking lutein and zeaxanthin supplements would improve visual processing speed. Their study results, published in April 15 issue of Archives of Biochemistry and Biophysics and the Public Library of Science (572:54-57), demonstrated such carotenoid supplementation does significantly improve visual processing speed.
Working off of prior research showing MPOD correlates to improved tCSF, the researchers set up a double blind, placebo controlled trial involving young adults (aged 18 to 32 years) from both the University of Georgia student body and from the local Athens, Georgia community; the subjects took either zeaxanthin alone (20 mg as EyePromise Zeaxanthin®, from ZeaVision), a combination formula (26 mg zeaxanthin, 8 mg lutein and 190mg omega-3 fatty acids, as EyePromise visual EDGE, from ZeaVision) or a placebo daily for four weeks. Researchers measured MPOD and temporal visual function on numerous separate visits.
They found a strong statistical relationship between MPOD and tCSF. Further, MPOD did not change in the placebo group, but it did increase significantly in both supplement groups. The increased MPOD translated to increased temporal processing speed in the supplement groups, but not in the placebo group. The study authors noted both MPOD and temporal visual speed increased about 20 percent overall, which is a larger change than expected. They could not offer a definitive reason why or how lutein and zeaxanthin improve visual processing, but they listed several possible reasons why they think the key may be in affecting brain function.
Significant improvements in tCSF were found in the parafovea, but since this area of the retina has minimal macular pigment the overall visual processing improvements must be partly or mostly in the brain. Further, increasing the macular pigment takes too long for the supplements to have acted as stimulants of the nervous system, but they are present in the brain and have a more active role than a passive one. They noted the possibility the carotenoids act to structurally change the neurons or glia cells in the brain to create more lasting improvement in processing speed.
Lead study author Billy Hammond, Ph.D., professor in the university’s Behavioral and Brain Sciences Department, detailed some of these study findings at 7th Annual Collegiate and Professional Sports Dietitians Association (CPSDA) conference this past May. He told attendees this is the first time researchers have been able to speed up visual processing speed using a nutritional approach with dietary zeaxanthin.
Scott Sehnert, president of CPSDA and director of sports nutrition at Auburn University, called vison and response time two of the most critical assets for athletes. He noted ZeaVision is a CSPDA partner and its EyePromise products featured in Hammond’s research are in the NSF Certified for Sport program. “Having NSF Certified zeaxanthin-based nutritional products will allow us as dietitians to stay ahead of the curve in terms of maximizing human performance," he said.