Research suggests that a Mediterranean diet may be the most protective against AMD. Photo: Nadine Primeau on Unsplash.

A number of studies have explored the connection between nutrition and supplements and the development or progression of age-related macular degeneration (AMD). To better understand where the current literature stands, researchers recently conducted a systematic review that found that a high intake of specific nutrients as well as antioxidant supplementation and a Mediterranean diet decrease the risk of progression of early to late AMD.

The study authors included studies published between January 2015 and May 2021 that were identified through a multi-database search. They assessed the certainty of evidence according to the GRADE methodology. The main outcome measures included development, progression and side effects of AMD.

Seven systematic reviews, seven randomized controlled trials and 13 nonrandomized studies were included. The researchers reported a high certainty of evidence for the association between high consumption of specific nutrients, such as β-carotene, lutein, zeaxanthin, copper, folate, magnesium, vitamin A, niacin, vitamin B6, vitamin C, docosahexaenoic acid and eicosapentaenoic acid, and a lower risk of progression of early to late AMD.

There was a moderate certainty of evidence that the use of antioxidant supplements and adherence to a Mediterranean diet was correlated with a decreased risk of progression of early to late AMD. Additionally, there was a moderate certainty of evidence that high alcohol consumption was linked to a higher risk of AMD development.

The study authors also found that supplementary vitamin C, vitamin E and β-carotene were not associated with the development of AMD. Supplementary omega-3 fatty acids were not associated with progression to late AMD. Both had a high certainty of evidence, according to the researchers.

Based on this systematic review, the study authors recommend low alcohol consumption to decrease the risk of AMD progression. Patients with early AMD who do not smoke should take the AREDS 1 formula, which includes vitamin C, vitamin E, β- carotene, zinc as zinc oxide and copper as cupric oxide.

“In addition, the preventive effect of lutein (10mg/day) and zeaxanthin (2mg/day) as supplements is plausible, making them a good alternative for β-carotene,” they noted. “Secondly, for persons with early AMD, we would recommend a Mediterranean diet, characterized by a high intake of vegetables, fruit, legumes, grains and nuts, a moderate consumption of fish, poultry, dairy and red wine, the use of olive oil instead of butter and a limited consumption of red meat.”

Future research should focus on personalized therapeutic and preventive approaches, according to the study authors, such as the connection between nutrition and immunological parameters.

Pameijer EM, Heus P, Damen JA, et al. What did we learn in 35 years of research on nutrition and supplements for age-related macular degeneration: a systematic review. Acta Ophthalmol. June 13, 2022. [Epub ahead of print].