Zeaxanthin is a carotenoid, an organic pigment that contributes to the yellow and orange colors in many plants. In the human body, it functions as a potent antioxidant, protecting cells from damage caused by unstable molecules called free radicals. Since humans cannot produce carotenoids, dietary intake of zeaxanthin is important for maintaining health.
Zeaxanthin’s Role in Eye Health
Zeaxanthin accumulates in high concentrations within the macula, a small, yellowish area in the center of the retina responsible for sharp, detailed central vision. This accumulation forms part of the macular pigment. A primary function in the eye is to act as an internal filter, absorbing high-energy blue light wavelengths that can damage retinal tissues.
Beyond light filtration, zeaxanthin provides antioxidant protection within the eye. It neutralizes free radicals, unstable molecules that cause oxidative stress and cellular damage to the retina. This action may reduce the risk of age-related eye conditions. Studies suggest adequate zeaxanthin levels can help slow the progression of age-related macular degeneration (AMD), a leading cause of vision loss in older adults.
Zeaxanthin also safeguards the crystalline lens, where cataracts can form. Oxidative stress contributes to cataract development, and zeaxanthin’s antioxidant properties may help prevent or slow their formation. Higher concentrations of macular pigment have also been associated with improved visual function, including enhanced contrast sensitivity and reduced glare sensitivity.
Dietary Sources of Zeaxanthin
Zeaxanthin is found in various colorful foods. Leafy green vegetables like kale, spinach, collard greens, and mustard greens are notable sources. Orange bell peppers offer high concentrations, providing approximately 1.7 mg per 100-gram serving.
Other vegetables contributing to intake include corn, broccoli, green peas, summer squash, pumpkin, Brussels sprouts, asparagus, and romaine lettuce. Fruits like goji berries, oranges, grapes, mango, and honeydew melon also contain this carotenoid. Egg yolks are another source, with their fat content enhancing zeaxanthin absorption.
Cooking methods can influence zeaxanthin’s bioavailability, potentially increasing its absorption. Consuming zeaxanthin-rich foods with healthy fats, such as olive oil, can also improve absorption due to carotenoids’ fat-soluble nature.
The Relationship Between Zeaxanthin and Lutein
Zeaxanthin and lutein are the only two carotenoids found in the human retina, forming the macular pigment. They often appear together in discussions of eye health because they work in partnership to protect the eye. Both are xanthophylls, a type of yellow pigment acting as an antioxidant and photoprotective agent.
While both are present in the macula, their distribution differs. Zeaxanthin is most concentrated in the central fovea, the very center of the macula responsible for sharpest vision. Lutein is more dominant in the peripheral regions. This distinct yet overlapping distribution allows them to collectively provide comprehensive protection across the entire macular area.
Together, zeaxanthin and lutein absorb harmful high-energy blue light and neutralize free radicals, safeguarding delicate photoreceptor cells from damage. Their combined presence helps maintain the structural integrity of retinal cells and supports overall visual function. This collaborative action explains why they are frequently paired in dietary recommendations and nutritional supplements.
Supplementation and Recommended Intake
Zeaxanthin supplementation may benefit individuals with low dietary intake or those at higher risk for age-related eye conditions like macular degeneration. Supplements provide a concentrated source of this carotenoid. Clinical studies have explored their efficacy in supporting eye health.
The Age-Related Eye Disease Study 2 (AREDS2) trial is a notable reference for zeaxanthin dosage. This study used a daily dose of 2 milligrams (mg) of zeaxanthin, typically combined with 10 mg of lutein, to assess its impact on age-related macular degeneration progression. Other research suggests 6-20 mg of lutein with 2 mg of zeaxanthin daily for eye health.
Zeaxanthin supplements are well-tolerated with few reported side effects at recommended doses. High doses might rarely lead to a harmless yellowing of the skin, but this is not a concern at standard intake levels. Some individuals might experience gastrointestinal discomfort from other ingredients in combination supplements, such as high doses of zinc, rather than from zeaxanthin itself.