Omega-3-fatty acids protect eyes

Diets rich in omega-3-fatty acids may slow the progression of early age-related macular degeneration (ARMD) to advanced disease.

Age-related macular degeneration is an eye disorder that affects the macula, the part of the retina responsible for central vision. It is primarily seen in patients older than 60 years and is a major cause of blindness. As the disease has no cure, preventing its occurrence or delaying its progression have become a public health concern. Some studies suggest the role of dietary factors like intake of high-dose antioxidants (vitamin C, beta-carotene and vitamin E) in reducing the risk and the protective role of lutein, zeaxanthin and omega-3 fatty acids.

Researchers from America studied 2924 subjects who were randomly assigned to receive one of four dietary supplement groups: placebo, antioxidants, zinc, or antioxidants plus zinc. They completed a food frequency questionnaire at the beginning of the study and underwent periodic general and ophthalmologic physical examinations.

It was found that regardless of which supplement was given, higher quantities of omega fatty acids lowered the risk of progression to advanced macular degeneration. In addition, a lower dietary glycaemic index correlated with a 24 percent reduced risk of progression. The glycaemic index (GI) measures how fast a food raises blood glucose levels. Refined carbohydrates have a high GI while fibre rich sources raise the blood sugar slowly.

It is thought that high-GI diets induce the production of compounds that ultimately lead to inflammation and the protective effect of omega-3 fatty acids may be through modulating these changes.

The researchers concluded that diet and, if necessary, supplementation can be  optimised for the prevention of acute macular degeneration. However, further studies are required as the effect of an intervention may vary by different stages of disease development and the interaction between different nutrient may also influence the effect.