To most of us they seem like ordinary events—catching the sunrise, seeing a master artwork in a museum, or looking at a loved one’s face. Yet, for the 285 million people around the world who are blind or vision impaired,¹ the full beauty of those images can only be imagined or remembered. For those individuals, a rainbow is seen under a cloudy haze, a grandchild can only be viewed with the center of the image blocked out, and a book can only be heard on audio. For many in this group, their view of the world is simply a black screen.

What makes that number so daunting is that 80% of all visually compromised cases are preventable. Many of these eye conditions, particularly those associated with age, like age-related macular degeneration (AMD) and cataracts, may have less of an impact with simple solutions like better nutrition.²

Promoting Health for a Lifetime
Good nutrition and good health begin at the very early signs of life when a baby is first starting to develop in utero. Your health throughout the lifespan continues to depend on what you eat as a child, as an adolescent, and as an adult. And while much can be done to enhance your later years by eating well while you’re young, you’re never too old to gain the benefits of eating right.

A key nutrient for eating right throughout a lifetime is lutein, a carotenoid found in dark leafy greens and colorful vegetables and fruits that is important for brain, eye, and skin health. A nutrient that is often found together with lutein is zeaxanthin. Often thought of as lutein’s “sister” since it is chemically similar, zeaxanthin is so much more, having a unique function all its own. It is most often found in the same foods as lutein and works with lutein in the body.

Of the 40-50 carotenoids in our diet, lutein and the two zeaxanthin isomers—RR-zeaxanthin (3R,3’R-zeaxanthin) and RS- (or meso-) zeaxanthin (3R,3’S-zeaxanthin)—are the only three found in the eye. These are called macular carotenoids. Unlike many other nutrients, lutein and zeaxanthin cannot be made by our bodies. Luckily, we can get them by enjoying a broad range of fruits and vegetables or through dietary supplements.

Since lutein and zeaxanthin isomers are yellow pigments, you might think they are only found in yellow foods like corn, egg yolks, and yellow squash. While those are all good sources of lutein and RR-zeaxanthin, they are even more prevalent in dark leafy greens like kale, spinach, and collard greens—their color hidden by the green pigment chlorophyll in those plants.

Other excellent sources of lutein and RR-zeaxanthin are kiwi fruit, grapes and zucchini.³ RS-zeaxanthin (or meso-zeaxanthin) can be found in 21 species of fish skin, shrimp shells as well as certain eggs.

Given how reluctant many people are to eat their green vegetables, it’s not surprising that intake of lutein and zeaxanthin is low. Men and women less than 50 years of age consume, on average, less than 2 mg/day. Many researchers, however, are using 12 mg of lutein and zeaxanthin per day to determine their effects on healthy vision.

Life in Focus with Lutein and Zeaxanthin
The macular carotenoids act as potent antioxidants in the eye. They protect our bodies against a process called oxidation. Oxidation can happen in the eye from the environment like light from the sun. In fact, just being alive causes oxidation; it is a natural process of aging.

Lutein and zeaxanthin isomers also play a direct role in vision. They are highly concentrated in a small area in the center of the retina called the macula. The macula is responsible for central vision and the sharpness with which we see things (known as visual acuity). Because the macula is yellow, lutein and the zeaxanthin isomers are often referred to as macular pigment.

Macular pigment enhances healthy vision by filtering light and enhancing detail and contrast. Studies suggest that macular pigment may benefit activities such as driving at night and protect against harmful effects that might occur after staring at a computer for too long.^4,5

Macular pigment density has also been shown in studies to increase the speed with which we process images and to help see in dim light.^6-8 Lutein and zeaxanthin may also help the nerves to the eye talk to one another—a process known as neuronal signaling.^9-11 These effects happen throughout our lives: as infants, while our vision is developing; as we mature during childhood; and as our eyes become more vulnerable with age.¹² Lutein and zeaxanthin are also found elsewhere in the eye: in the iris, the lens, and photoreceptors.¹³

Effects of High Energy Blue Light
High-energy blue light is part of the visible spectrum of light. Most of us know to protect our eyes against the sun, but high-energy blue light from digital screens and energy-efficient lighting bombards our eyes daily and may lead to eye strain and fatigue, and eventually compromised vision. Fortunately, lutein and the zeaxanthin isomers support eye health by acting as potent antioxidants and filtering high-energy blue light.^14,15

The B.L.U.E. (Blue Light User Exposure) study is a 6-month randomized, double-blind, placebo-controlled trial in young, healthy subjects with long duration exposure to indoor and outdoor high energy blue light who supplemented with a proprietary source of 20 mg lutein and 4 mg zeaxanthin isomers (in a 5:1 ratio) or placebo. At the end of the study, significant improvements were observed in visual performance, sleep quality, and side effects of prolonged screen time, including eye strain and fatigue.¹⁶

In another study published in Nutrients, the same proprietary source of lutein and zeaxanthin isomers (also in a 5:1 ratio) was shown to protect photoreceptors against blue light damage by mitigating oxidative and endoplasmic reticulum stress—a primary mechanism associated with photoreceptor damage and visual impairment.

While the protective qualities of the macular carotenoids are well established, the mechanisms by which they protect have not been well explored. This study effectively showed for the first time that blue light causes damage to the retinal tissue by not only promoting oxidative stress, which has been reported earlier, but also increasing stress in the endoplasmic reticulum. The lutein and zeaxanthin isomers used in this study were shown to downregulate the genes involved in causing endoplasmic reticulum stress, and thereby protect the sensitive photoreceptors when exposed to blue light.¹⁷

As the breadth of science surrounding the importance of lutein and zeaxanthin for eye health grows and expands into other health benefits such as brain and skin health, it will be interesting to see the continued evolution of the macular carotenoids unfold before our very eyes.

1. Global Data on Vision Impairment 2010, World Health Organization
2. National Institutes of Health, National Eye Institute
3. Br J Ophthalmol 1998;82:907–910
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5. Appl Ergon. 2009 Nov;40(6):1047–54
6. Ophthalmic Physiol Opt 2005;25:315–9
7. Ophthalmic Physiol Opt 2010;30:351–7
8. Exp Eye Res 2010;91:896–900
9. Optom Vis Sci Off Publ Am Acad Optom. 2007 Sep;84(9):859–64
10. Optom Vis Sci Off Publ Am Acad Optom. 2008 Feb;85(2):82–8
11. Nutr Rev. 2005 Feb;63(2):59–64
12. Nutr Rev. 2008 Dec;66(12):695–702
13. Nutr Rev. 2008 Dec;66(12):695–702
14. D Max Snodderly. Am J Clin Nutr. 1995; 62 (suppl): 1448S-61S;
15. Bone RA, et al. Exp Eye Res. 1997; 64: 211-218
16. Stringham. Foods. 2017 Jun 29;6(7):47. doi: 10.3390/foods6070047.
17. Nutrients 2018, 10(7), 842