As mentioned beforehand, several studies have suggested lutein and zeaxanthin may lower the risk for forming age-related macular degeneration (AMD) and cataracts.
Beside this risk reduction to develop AMD or progress into advanced status of AMD, a randomized controlled trial in patients with AMD found in addition that lutein supplementation with 10 mg/day slightly improved visual acuity after one year compared to a placebo (11).
Another study in patients with cataracts or AMD found that lutein supplementation (3 times 15 mg/week) for up to two years slightly improved visual acuity and glare sensitivity (18). A recent meta-analysis conducted on the data from seven separate clinical studies found that supplementation with lutein increased MPOD values while simultaneously improving visual acuity and contrast sensitivity in AMD subjects (39).
Many parameters of visual performance (e.g., contrast sensitivity) in healthy subjects are compromised under glaring light conditions. As lutein and zeaxanthin are thought to block out blue light and to shield from strong light, they may increase the eyes’ tolerance for bright lights (e.g., glare from the sun or blinding headlights at night).
In a study which was published in 2008, it was found that visual performance could be improved in healthy eyes of young adult subjects by supplementation with lutein and zeaxanthin (19). Additionally, these results were confirmed in a follow-up randomized, double-blind, placebo-controlled study published in 2014 (40) and in a study published in 2016 (41). These studies showed that supplementation with lutein and zeaxanthin resulted in significantly decreased photostress recovery time (i.e., the time it takes to recover from a blinding flash of light) and increased chromatic contrast which was related to the increase in MPOD values following supplementation. These benefits were accompanied by an increased tolerance to glaring light. These visual performance improvements are very important because they demonstrate that lutein and zeaxanthin supplementation provides benefits in the human eye regardless of a person’s age or the presence/absence of AMD.
Another aspect of lutein and zeaxanthin is its capability to absorb blue light. Blue light has become important because of the increased exposure that people have to blue light sources such as computers, video display screens, tablets, e-readers, and cell phones. Additionally, compact fluorescent and LED based lighting emit significant amounts of blue light (42). Given that lutein and zeaxanthin absorb the harmful wavelengths of blue light and reduce damage in the eye, these nutrients have been shown to contribute to reducing the progression of AMD which is in part a result from harmful blue light exposure. Although additional studies are needed to demonstrate the efficacy in human eyes, a study has already shown that ingestion of lutein and zeaxanthin reduced eye fatigue associated with prolonged exposure to light from a computer (43).
Lutein and zeaxanthin have been shown to support healthy vision in adults. Emerging research has shown that the eye benefits of these important nutrients are also beneficial for the developing eye of infants. Lutein and zeaxanthin have been found in the eye of fetuses as early as 17 to 22 weeks of gestation (44). In addition, findings revealed that lutein is not only present in the mother’s bloodstream during pregnancy, but also that it typically increases during pregnancy and then decreases postpartum. This research also showed that lutein is present in cord blood which provides nutrients to the fetus. Lutein has also been found in breast milk throughout the entire nursing period (45, 46). In total, these findings provide a compelling argument for the importance of lutein to be provided in infant formula, especially given the fact infant formula is given to many babies in place of breast milk.
Authored by Dr Peter Engel in 2010, reviewed and revised by Jonas Wittwer on 13.06.2017
