The eye, especially the retina and even more so the macula, is particularly prone to photo- and oxidative-damage. This damage can occur from natural sunlight, artificial light from light bulbs or computer screens, exposure to environmental factors, and oxidants produced as a result of the high metabolic rate of the eye. Over time these insults add up and there is a general decline in visual acuity as we age.
Of particular concern are the environmental factors that come in contact with the eye and the damaging rays that enter the eye. Just like high-intensity light (UV radiation) from the sun can burn and damage our skin, these same rays can also damage structures of the eye. If you think about it, it is an interesting dilemma the eye has to balance. On one hand, it needs to let light in so we can see. But on the other hand, it has to minimize how much light is let in to help reduce damage to the eye.
To help the eye combat the harmful effects of environmental factors and light it has developed an interesting mechanism of concentrating specific nutrients to help minimize this damage. Some of these nutrients include flavonoids, vitamin C, zinc, lutein, and zeaxanthin. Flavonoids and vitamin C help promote healthy blood vessels to ensure nutrient delivery. Vitamin C and zinc work together to provide antioxidant protection. Zinc additionally helps to transport vitamin A, an essential nutrient for vision, into the eye. The central portion of the macula—the portion of the retina where most light is focused—contains a dense yellow pigment called macular pigment. Macular pigment helps protect the sensitive receptors in the macula from the potentially harmful effects of high-intensity, shorter wavelengths of light (also referred to as blue light). The nutrients that make up this macular pigment are the carotenoids, lutein, and zeaxanthin.
Carotenoids make up a very large family of over 750 naturally occurring plant pigments. They are the compounds in fruits and vegetables that tend to give them their red, orange, and yellow color. What is so interesting is that with all the different carotenoids found in nature, the eye has developed the ability to specifically and selectively concentrate lutein and zeaxanthin in the eye, specific neurons involved in vision, and certain regions of the brain. Together with these other nutrients, the eye is well equipped to cope with the daily stresses.
Because our bodies cannot synthesize lutein, zeaxanthin, vitamin C, zinc, and flavonoids, they must be obtained from the diet or a nutritional supplement. Research has shown that levels of these eye-protecting nutrients correlate to the amounts we consume. Levels of these nutrients begin to increase in as short as a few days and continue to increase as long as they are being consumed. Unfortunately, once consumption of these nutrients stops, levels begin to decline as rapidly as they increased. Therefore, it is important to consistently eat a healthy diet and take a nutritional supplement that supports eye health.
Science of Visionex®
When light shines through the inner layers of the retina, it is filtered through the yellow pigment of the macula. The macula is especially vulnerable to oxidative damage because it has a high metabolic rate and because the light focused on it encourages the production of free radicals. The yellow pigment helps protect the sensitive receptors in the macula from the potentially harmful effects of short-wavelength blue light.*
Macular pigment includes the carotenoids lutein and zeaxanthin, an isomer of lutein, which protect eye health in two ways: first as filters that absorb some of the high-energy blue light and, second, as antioxidants that combat light-induced free radicals and other oxidants.
Average levels of macular pigment tend to be low, especially in those who do not eat many fruits and vegetables. And maintaining an adequate level is important, not only for long-term eye health, but also because macular pigment optical density (MPOD) has been linked to visual performance. Supplementing with lutein and zeaxanthin can help increase MPOD, which helps support visual acuity and maintain long-term eye health as well as tolerance to glare, improved contrast, and reduced photostress.*
In addition to lutein and zeaxanthin, the Visionex formula contains three other important nutritional aids to eye health: bilberry extract, vitamin C, and zinc. The bilberry fruit is rich in antioxidant anthocyanosides and has been shown to help retain healthy capillaries, including those in the eye. Vitamin C provides additional antioxidant protection, especially to the retina and cornea, where the concentration of vitamin C is significantly higher than that found in the blood. And zinc appears to provide an additive effect to antioxidants in promoting good visual acuity.*
Over the past two decades, there have been significant advances in research related to nutrition and eye health. Researchers have a better understanding of how nutrition helps promote healthy vision and decreases the risk of developing age-related eye disorders. The first AREDS study (Age-Related Eye Disease Study) was sponsored by the National Eye Institute. Research had previously linked eye health and nutrition, but this study sought to look more in depth at the potential connection. According to the authors of the study, their purpose was to “learn more about the natural history and risk factors of age-related macular degeneration (AMD) and cataract” specifically and to “evaluate the effect of high doses of antioxidants and zinc on the progression of AMD and cataract.”
The study involved 3640 subjects, ages 55-80. The subjects in the test group were administered daily amounts of 500 mg vitamin C, 400 IU vitamin E, 15 mg beta-carotene (25,000 IU vitamin A equivalents), and 80 mg zinc. The results showed that supplementation slowed AMD by 25% and visual acuity loss by 19% in high-risk individuals. These results have since been confirmed in several smaller studies. In the years since the original AREDS study, new research has also shown beneficial results from lutein, zeaxanthin, and the omega-3 fatty acids EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid). Read more about the health benefits of Omega-3 fatty acids here.
Another landmark study was the Lutein Antioxidant Supplement Study (LAST) published in the journal Optometry. The results of this study showed that AMD symptoms might be improved through purified lutein supplementation or a supplement mix of lutein and other antioxidants such as vitamin A, vitamin C, vitamin E, and beta-carotene. The dosage of lutein and zeaxanthin used in the study were 10 mg and 2 mg, respectively.
More recent studies have shown that nutritional interventions can not only reduce the risk for diseases of the eye but also help support vision in general. For example, Stringham JM, and Hammond BR performed a study on 40 young, healthy subjects with an average age of 23.9. They were assigned to receive daily supplements of lutein (10 mg) and zeaxanthin (2 mg) for six months. The subjects’ eyes were then tested for the effects of glare as experienced in everyday situations, including being outdoors on bright days, lengthy sessions of looking at a computer monitor, and nighttime exposure to oncoming headlights. Following six months of supplementation, the participant’s average macular pigment optical density (MPOD) increased significantly from the average value at the beginning of the study. Higher MPOD has been linked to increased visual acuity. After testing the subjects for their performance in visual tasks researchers concluded that four to six months of supplementation with lutein and zeaxanthin significantly improved visual performance in high glare situations.
AREDS 2, which was published in 2013, tested several variations of the original formula. One was using lutein/zeaxanthin instead of beta-carotene, one included fish oil, and one included a significantly reduced zinc level (25 mg). Removing the beta-carotene did not affect the outcomes, so it concluded that lutein and zeaxanthin were safe and effective alternatives to beta-carotene. The reduced zinc level (25 mg) was just as effective as the high zinc formula. Adding EPA and DHA (omega 3 fatty acids) did not provide any additional benefit in reducing AMD progression. So, based on the actual results of the study, it would make sense to use lutein and zeaxanthin in place of beta-carotene, healthy zinc levels, maintain the same or similar levels of vitamins C and E and copper.
The last study involved more than 100,000 participants from the Nurses’ Health Study and the Health Professionals Follow-up Study. All participants were aged 50 years or older and were free of diagnosed AMD, diabetes mellitus, cardiovascular disease, and cancer (except non-melanoma skin cancer) at baseline. The researchers analyzed carotenoid intake based on dietary food frequency questionnaires at baseline and follow-up, and then calculated predicted plasma carotenoid scores. The results of this study found that participants with the highest average plasma lutein and zeaxanthin levels had a 40% reduced risk of developing advanced AMD compared to those with the lowest average levels. The authors concluded “lutein and zeaxanthin form macular pigments that may protect against AMD by reducing oxidative stress, absorbing blue light, and stabilizing cell membranes,” the authors explain.