Nutrients that Support Eye Health

Macular degeneration, also known as age-related macular degeneration (AMD), is one of the main reasons for vision loss in older adults and is the most common cause of legal blindness in the U.S. and other developed countries. The onset of symptoms and their severity can vary depending on the individual and the stage and type of AMD — wet or dry. AMD can occur in one or both eyes, and the stage of AMD — early, intermediate or late — can be different in each.

The development of AMD, like many health conditions, is multifactorial. Smoking cessation is considered the main modifiable risk factor for AMD; whereas regular physical activity may help to lower the risk or delay its progression. Studies have also looked at hypertension and other cardiovascular diseases and although results have been conflicting, maintaining blood pressure and lipid levels within healthy ranges is considered helpful in lowering the risk of AMD, or slowing the progression of vision loss once diagnosed.

Observational data suggest that people who consume ample dietary sources of lutein and zeaxanthin, and omega-3 polyunsaturated fatty acids, especially from fatty fish, have a reduced risk of developing AMD. Several studies have demonstrated an inverse relationship between fish consumption and the risk of AMD or its progression, so including good sources regularly is encouraged. In addition, an eating pattern that includes a variety of foods, especially fruits and vegetables that are dark green, red and orange in color is beneficial and recommended for eye health.

Dietary sources of beta-carotene, vitamins C and E, lutein, zeaxanthin, zinc and copper, as well as supplements, have demonstrated favorable effects on delaying the progression of advanced AMD. The Age-Related Eye Disease Studies, also known as AREDS and AREDS2, evaluated the effect of supplements on the progression of AMD. A combination of supplements appeared to generate the most favorable effects on AMD symptoms; however, due to the increased risk of lung cancer in smokers newer formulations based on AREDS2 and without beta-carotene have been developed.

Follow-up research on AREDS data continues to investigate the role of various nutrients and dietary patterns, such as the Mediterranean diet, and their possible influence on AMD outcomes. A recent post hoc analysis, using validated food frequency questionnaires from AREDS and AREDS2 participants, categorized intake of select nutrients based mostly on dietary sources; although estimates for carotenoids, selenium, DHA and EPA included amounts derived from supplements. Higher intakes of vitamins A, B6, and C, folate, β-carotene, lutein/zeaxanthin, magnesium, copper and alcohol were associated with decreased progression to late AMD, whereas increased risk was associated with higher saturated and monounsaturated fatty acid intake. In this case, meat and dairy products were suspected as the sources of MUFAs due to the high correlation with saturated fat intake.

The authors also noted that the protective effect of certain nutrients could be achieved by following the Recommended Dietary Allowance. For other nutrients, intake would need to be a lot higher with the potential for dietary sources and supplements to act in a complementary manner in decreasing the risk of late AMD. Although the formulation of supplements based on the AREDS trials are an important consideration for people already diagnosed with intermediate or advanced AMD, supplementation for prevention of AMD is not recommended at this time. The American Academy of Ophthalmology recommends that antioxidant vitamin and mineral supplementation based on the AREDS2 trial be considered for patients with intermediate or advanced AMD to slow its progression. However, with any supplements, there is a concern about consuming an excess and the potential for adverse effects. All the supplements in the AREDS trials were high doses, so the AAO recommends supplementation be reviewed by the patient's primary care physician.

Registered dietitian nutritionists can work with patients and clients to ensure they are obtaining the nutrients needed for eye health and provide education regarding the safe and appropriate use of dietary supplements, if warranted.

References:

• National Institute of Health (NIH), National Eye Institute (NEI). Facts About Age-Related Macular Degeneration. Accessed May 23, 2022.
• Agrón E, Mares J, Clemons TE, Swaroop A, Chew EY, Keenan TDL; AREDS and AREDS2 Research Groups. Dietary Nutrient Intake and Progression to Late Age-Related Macular Degeneration in the Age-Related Eye Disease Studies 1 and 2. Ophthalmology. 2021 Mar;128(3):425-442. doi: 10.1016/j.ophtha.2020.08.018.
• Flaxel CJ, Adelman RA, Bailey ST, Fawzi A, Lim JI, Vemulakonda GA, Ying GS. Age-Related Macular Degeneration Preferred Practice Pattern^®. Ophthalmology. 2020;127(1):1-P65. Doi: 10.1016/j.ophtha.2019.09.024. Accessed May 23, 2022.
• Broadhead GK, Grigg JR, Chang AA, McCluskey P. Dietary modification and supplementation for the treatment of age-related macular degeneration. Nutr Rev. 2015;73(7):448-462.
• The Age-Related Eye Disease Study 2 (AREDS2) Research Group. Lutein + Zeaxanthin and Omega-3 Fatty Acids for Age-Related Macular Degeneration: The Age-Related Eye Disease Study 2 (AREDS2) Randomized Clinical Trial. JAMA. 2013;309(19):2005-2015. Doi:10.1001/jama.2013.4997. Accessed June 19, 2015.