People who follow a fruit-rich Mediterranean diet that is high in caffeine may be more than a third less likely to develop age-related macular degeneration (AMD), new research has suggested.

The Mediterranean diet – which emphasises eating fruits, vegetables, whole grains, legumes, nuts, healthy fats and fish, and limiting red meat and butter – is understood to offer various health benefits, such as improved heart health and reduced risk of cancer.

Researchers at the University of Coimbra in Portugal studied 883 people aged 55 or older between 2013 and 2015 to determine whether adherence to the diet would have an impact on the risk of AMD. Of those, 449 had AMD in its early stages before vision loss and 434 did not have AMD.

Participants were given a questionnaire asking how often they ate foods associated with the Mediterranean diet, with those who adhered closely to the diet scoring higher (above six) on a scale of zero to nine than those who did not.

Researchers found that higher diet adherence scores meant lower AMD risk. Of those who did not closely follow the diet, 50% had AMD. Of those who did closely follow the diet, only 39% had AMD, representing a 35% lower risk compared to those who did not adhere to the diet.

Fruits were especially beneficial, with those who consumed 150 g or more of fruit a day found to be almost 15% less likely to have AMD.

Higher consumption of antioxidants such as caffeine, beta-carotene and vitamins C and E were also found to be protective against AMD. Of those who consumed high levels of caffeine, 54.4% did not have AMD while 45.1% did.

“This research adds to the evidence that a healthy, fruit-rich diet is important to health, including helping to protect against macular degeneration,” Dr Rufino Silva, lead author of the study and professor of ophthalmology at the University of Coimbra, stated. “We also think this work is a stepping stone towards effective preventive medicine in AMD.”