Veggies, fish and fruits: How much to eat to reduce AMD risk?
Following a diet consisting of vegetables 200 g per day, fruit two times per day and fish two times per week is good advice for individuals at risk of age-related macular degeneration (AMD), as it yields a significant reduction in the risk of the eye disease, according to a recent study.
“Our findings are consistent with recent studies on dietary patterns and AMD,” researchers said. [Ophthalmology 2014;121:1428-1434.e2; Am J Ophthalmol 2014;158:118-127.e1; Am J Clin Nutr 2015;102:1196-1206]
“Although similar conclusions can be drawn from these studies, the novelty of our research was to explore minimal levels for intake, which helps to translate findings into clinical recommendations,” they added. “Given the low adherence to healthy food patterns, the current evidence for a beneficial effect [at minimal consumption levels] may help alter lifestyles in individual patients as well as in the population at large.”
The study included 4,202 AMD-free participants aged ≥55 years from the Rotterdam Study. Researchers graded incident AMD on fundus photographs and collected dietary data using a validated 170-item food frequency questionnaire.
Over a mean follow-up of 9.1 years, 754 individuals developed AMD. Compared with those who did not develop the disease, AMD patients were less frequently diagnosed with hypertension (49.5 percent vs 52.8 percent; p=0.03) and had lower fish intake (median, 7.4 vs 6.6 g/day; p=0.03). [Am J Ophthalmol 2019;198:70-79]
The proportion of participants achieving the minimum intake targets of vegetables (≥200 g/day), fruit (twice/day) and fish (twice/week) was 30.6 percent, 54.9 percent and 12.5 percent, respectively. In regression models, eating two portions of fish per week was associated with a 24-percent reduction in the risk of incident AMD (hazard ratio [HR], 0.76; 95 percent CI, 0.60–0.97).
Meanwhile, only 3.7 percent of individuals in the cohort were consuming the minimum intake targets of all three food groups, but adherence to this pattern yielded a greater risk reduction (HR, 0.58; 0.36–0.93).
Individuals who consumed the recommended intake levels of fish, vegetables and fruit were younger, less likely to smoke and had higher household income compared with those who did not. However, these factors did not attenuate the risk-lowering benefits of the dietary pattern.
According to researchers, carotenoids, folate and vitamin B12 are among the potential nutrients that could explain the associated lower risk of AMD with the intake of fish, vegetables and fruit.
Carotenoids such as lutein and zeaxanthin form the major components of macular pigment and are involved in maintenance of the morphologic and functional integrity of the retina. On the other hand, folate and vitamin B12 play an important role in DNA methylation, with dysregulation possibly leading to increased serum levels of homocysteine, which contributes to an increased risk of AMD. [Int J Retina Vitreous 2016;2:19; Am J Clin Nutr 2016;103:1135-1144; Am J Clin Nutr 2013;98:129-135]
“Notwithstanding all limitations [to the present study], a good advice that ophthalmologists and other eye care providers can give to patients at risk of AMD is a diet consisting of a large variety of vegetables, fruit and fish,” researchers said.
While the amount advised is a minimum, its consumption will still prove to be a challenge to the average elderly person, they added. “[Thus], a recommendation of a lifestyle including a healthy diet, refrainment from smoking, and regular exercise should be part of any counseling session for those at risk of AMD progression.”