By Ginger Hultin, MS, RDN, CSO
Eyesight is a critical sense to protect, especially as a person ages. Macular degeneration, cataracts and other age-related deterioration of the eyes are real concerns. You may have heard suggestions such as “eat more carrots to improve your eyesight” or seen supplements targeted towards eye health. Does diet make a difference and are supplements indicated? Read on to learn more about foods and supplements for healthy aging of the eyes.
The vitamin with the largest body of research in support of eyesight is vitamin A; likely the reason you’ve been told to eat your carrots as a child. Orange vegetables like carrots and squash are packed with this fat-soluble vitamin as are green leafy vegetables. Eggs and dairy are also sources of vitamin A. Vitamin A is converted from the carotenoid beta-carotene, so you may hear both of these terms used when discussing eye health. These compounds are both in the carotenoid family of antioxidants.
Lutein and zeaxanthin are other naturally occurring carotenoids found in green leafy vegetables such as spinach and kale that are critical for eye health. Lutein is a pigment in plants and zeaxanthin is an isomer (another version) of lutein. These compounds are found in high levels in foods such as green vegetables, egg yolks, kiwi fruit, grapes, orange juice, zucchini, squash, and pistachio nuts. Lutein and zeaxanthin are the only carotenoids found in the macular region of the retina in the eye and act as antioxidants in that area of the body. They also appear to play a role in trapping short-wavelength light in the eye, so these antioxidants play very important roles in eye health. Though studies remain mixed on how well increased lutein works for preventing age-related macular degeneration, doses ranging from 2.2-40mg of lutein has been observed in studies and dietary sources are easy to increase; no supplements needed!
Other compounds that appear to support eye health include vitamin C, vitamin E, and zinc. These vitamins and minerals are found in plentiful amounts in the diet. Get vitamin C from citrus like oranges and mandarins, berries such as strawberries, or bell peppers – any color you like best. Vitamin E is found in nuts, seeds, and olive oil and is another fat soluble vitamin like vitamin A. Zinc is a mineral and the richest sources are seafood, especially oysters, but are also found in other meats and seeds from pumpkins and squash. One large study on the effect of 500mg vitamin C, 400IU vitamin E, 15mg beta carotene, 80mg zinc and 2mg copper found a 25% reduction in loss of visual acuity in those who took the supplement when compared to those who did not.
Keep in mind that any vitamin or mineral taken in excess can cause negative effects. For example, excess vitamin A can cause acute or chronic toxicity and too much of this vitamin can actually lead to eye or liver damage. Vitamin A and beta carotene supplementation have been linked to increased risk of certain cancers. Lutein appears safe in a variety of studies including those on toxicity when tested in animals. Other factors for eye health include staying hydrated, not smoking, getting assessed for diseases that damage the eyes such as diabetes and wearing UV eye protection. The safest way to protect your eyes is to visit an eye specialist on a regular basis and to eat a diet rich in a variety of vitamin, minerals, and antioxidants from plant sources. And yes, definitely eat your carrots!
Natural Medicines Database. Eye Disorders. https://naturalmedicines.therapeuticresearch.com/databases/medical-conditions/e/eye-disorders.aspx. Updated 5/24/16. Accessed 8/24/16.
Natural Medicines Database. Lutein. https://naturalmedicines.therapeuticresearch.com/databases/food,-herbs-supplements/professional.aspx?productid=754. Updated 8/27/15. Accessed 8/24/16.
Chadwick M, Trewin H, Gawthrop F, Wagstaff C. Review Sesquiterpenoids Lactones: Benefits to Plants and People. Int. J. Mol. Sci. 2013;14:12780-12805.