by People often turn to supplements or supplements to prevent or slow the progression of macular disease, but new Australian nutritional guidelines suggest that the concept of ‘food synergy’ may be more effective. So what is the ideal macular disease diet?
Eye health care professionals often advise their patients on diet. In fact, a survey of Australian optometrists found that two-thirds of practitioners regularly discuss the impact of diet on eye disease, and 91% regularly recommend nutritional supplements to age-related macular degeneration (AMD) patients. Given the emphasis on positive eating habits, it may be surprising that there are currently no official nutritional guidelines for AMD.
But there is a clear need for evidence-based dietary information, according to the Macular Disease Foundation Australia (MDFA), which has worked with Indigenous academics to provide important insights into the types of eating patterns that reduce the likelihood of – and even protect against – macular disease. against – AMD. .
In May 2024, as part of its Macula Month awareness campaign, MDFA is launching updated Nutrition Guidelines for AMD. The organization recently conducted a systematic review assessing the strength of evidence for dietary patterns, foods, nutrients and supplements to prevent and/or slow the progression of AMD.
According to MDFA, randomized controlled trials (RCTs) have reported the efficacy of multi-antioxidant supplements in reducing the risk of late AMD. Epidemiological research in the 1990s first noted an association between certain antioxidant-rich foods and fish in lowering the risk of AMD. Meanwhile, the high intake of vegetables, fruits, fish and plant-based proteins in traditional Mediterranean and Asian diets is associated with a lower incidence of AMD.
MDFA’s updated dietary recommendations are based on the first systematic review of all published systematic reviews investigating dietary patterns, food, nutrients, nutritional supplements and AMD, conducted in collaboration with the University of Sydney. The organisation’s CEO, Dr Kathy Chapman, has a PhD in public health promotion and started her career as a dietician.
To develop the guidelines, systematic reviews were included if they investigated an association between any diet, food, macronutrient, micronutrient and/or dietary supplements and AMD (early, intermediate, late, atrophic and/or neovascular) in humans adult.
Interpreting the large number of published studies linking different eating patterns and food groups is a major undertaking and required GMFA to analyze the design of both observational studies and RCTs. Observational studies – such as cohort studies – that follow large numbers of people in the population over time and help inform links to eating patterns and individual foods. RCTs also help to understand whether dietary supplements taken in capsule form are effective. From 575 studies identified in the literature search, 21 systematic literature reviews were identified for analysis.
Chapman says a healthy diet can help prevent age-related macular degeneration (AMD) by providing a wide range of potentially protective antioxidants such as omega-3 fatty acids, lutein, zeaxanthin, vitamins C and E, and zinc.
“Eating patterns that increase the consumption of these nutrients protect against oxidative stress, inflammation and cellular damage in the eyes, reducing the risk of developing AMD or slowing its progression. A healthy, macula-friendly diet is an important part of prevention and treatment for AMD,” she says.
“A key finding in our study is that it is important to consider overall eating patterns rather than focusing on individual nutrients and foods. People often try to improve their diets with nutritional supplements or so-called ‘superfoods’, but more and more studies are pointing to the benefits of an overall healthy eating pattern with a wide range of plant-based foods.”
‘Food synergy’, the joint action of food ingredients on overall health, is an important message that the GMFA is asking practitioners and the wider macular disease community to take note of.
Studying foods that are regularly eaten together may show an improved effect on health, compared to studying foods or nutrients individually. MDFA says this could explain why Mediterranean and Asian eating patterns were consistently linked to a lower risk of developing AMD – and slow progression – while the evidence was less conclusive for high intake of foods and individual nutrients.
Mediterranean and Asian diets include a high intake of fresh fruit and vegetables, fish, nuts and seeds, with little meat and dairy. While Asian-style diets have a high intake of rice, soy products and other plant-based foods, the Mediterranean diet is based on the regular use of olive oil and grain products. Both have a high intake of fish, foods rich in omega-3 fatty acids, and antioxidants – foods with the strongest protective associations.
In the MDFA study, omega-3 polyunsaturated fatty acids and fish consumption were frequently reported to be protective against AMD.
Foods rich in lutein and zeaxanthin, such as dark green leafy vegetables (such as kale and spinach), broccoli, peas, corn and eggs, are likely to be associated with a reduced risk of developing or progressing to late AMD. Multi-antioxidant supplements have been associated with slowing AMD progression, but not preventing it.
According to MDFA, new evidence indicates that more than one standard alcoholic drink was likely associated with a higher risk of developing early AMD. High consumption of meat – especially red and processed meat – was also associated with a likely increased risk of developing early AMD.
MDFA says its findings suggest that following a Mediterranean diet may protect against both early and late AMD, and that following an Asian-style diet may slow the progression of late AMD. Research has shown that inflammation plays a role in the development of chronic conditions such as AMD. A Mediterranean diet has been linked to lower levels of oxidative stress biomarkers. This may be due to the antioxidant and anti-inflammatory properties of fruits, vegetables and fish.
“As part of our Macula Month awareness program, we urge all eye health professionals to encourage their patients to follow healthy diets,” says Chapman.
“Nutritional information is critical to holistic patient care as it impacts physical health, mental well-being and overall quality of life. Understanding nutritional needs helps manage chronic conditions, such as AMD, and supports recovery from illness, improves energy levels, promotes mental clarity, and enhances emotional well-being, leading to comprehensive and effective healthcare outcomes .”
NOTE: For a copy of the updated MDFA Nutrition Guidelines for AMD, visit here.
Further reading
Macular disease report 2024
Over $700,000 in funding awarded to six macular disease research projects
