Lutein Zeaxanthin: Botanical nutrients for macular health.
What are Lutein & Zeaxanthin?
Lutein is a natural antioxidant pigment known as a xanthophyll carotenoid. The compound is abundant in various plants and is found in the human eye, particularly in the retina. Another related xanthophyll available from botanical sources, zeaxanthin is also present in the eye, notably concentrated in the tiny spot of the retina called the macula which is responsible for sharp central eyesight. Lutein and zeaxanthin are also the only two antioxidants that are naturally present in the eye's lens. Because of their complementary roles in the body, these two carotenoid antioxidants are sometimes regarded as "sister compounds."
Due to their prominence in the eye's retina and macula, and to a lesser extent its lens, these carotenoids are considered to be important nutrients for overall vision health. However, since the body cannot generate them, they must be obtained from diet or supplementation. Although the pigments are both naturally yellow in color, they are found in foods of various hues. Dietary sources of lutein include leafy greens such as spinach, as well as corn and zucchini. Another plant that is especially rich in these xanthophylls is the marigold flower (Calendula officinalis), which is the primary source for lutein zeaxanthin supplements.Egg yolks are yet another dietary source of both carotenoids.
Eye Health Benefits
These pigments act as antioxidants that help to neutralize unstable molecules known as free radicals. Free radicals smash against healthy cells, causing damage and creating a body state known as oxidative stress. In the eyes, free radical damage is associated with vision health problems such as macular degeneration and lens clouding.
Lutein and zeaxanthin are notable antioxidants for vision health because they naturally migrate to the eyes and settle in the retina and macula. This makes the two compounds uniquely qualified to neutralize the free radicals that can degrade and damage the eyes' delicate photoreceptors. Scientific research has shown that the antioxidant capacity of these xanthophylls also promotes vision health by protecting the eyes from harmful blue light and ultraviolet rays emitted from the sun. In effect, lutein and zeaxanthin work as internal sunglasses that filter out and quench dangerous light frequencies.
Intake of these xanthophylls is also associated with greater macular pigment optical density (MPOD). Higher MPOD has been associated with optimal vision health, including better hyperacuity. Research has found that MPOD may decline with age, making it a significant indicator for vision issues, especially macular degeneration in seniors. Lutein zeaxanthin intake supports healthy MPOD levels and may help contribute to a positive long-term vision outlook.
These compounds' well-documented associations with healthy eyesight have led to extensive scientific investigation. The pigments have been most widely studied in relation to age-related macular degeneration (AMD), an eye issue that involves the breakdown of the macula, primarily in those age 60 and older.
The Lutein Antioxidant Supplementation Trial (LAST) was one large study that appears to support lutein's vision-protective role. Conducted at Chicago's Medical Center Eye Clinic, the LAST study tracked 90 veterans with chronic AMD. Results of the 12-month, double-blind, placebo-controlled study showed that when the pigment was taken at 10 mg daily, either alone or accompanying other vitamins and minerals, it led to significant improvements in visual acuity, contrast sensitivity and overall vision quality in AMD patients.
The United States National Eye Institute (NEI) has also published research suggesting these antioxidant compounds' benefits to eye health. In the NEI's Age-Related Eye Disease Study (AREDS), a combination of antioxidants and zinc was found to reduce the risk of developing late-stage AMD by 25%. The follow-up study, AREDS2, found that an antioxidant combination that included lutein and zeaxanthin appeared to be 18% more effective than the original AREDS formula, while also being easier for study subjects to absorb.
For those who may have challenges obtaining these carotenoid antioxidants from diet alone, nutritional supplements may be advisable. Lutein and zeaxanthin are often blended together, though they may be presented as separate standalone nutritional supplements, as well. They may also be also found in AREDS2 nutritional supplements that are calibrated to match the formulation used by the National Eye Institute in some of its research. Lutein zeaxanthin supplements are typically manufactured from natural botanical sources such as marigold blooms and paprika.