Two nutrients found in green and yellow vegetables may help protect against age-related macular degeneration, a new study has found.
The nutrients, lutein and zeaxanthin, are both carotenoids -- compounds that give many fruits and vegetables a yellow colour. The U.S. researchers found that the compounds seem to help ward off AMD, the most common cause of blindness among the elderly.
"No clear associations with other nutrients were seen," including the vitamins C and E and beta-carotene, note the researchers, led by John Paul SanGiovanni of the National Eye Institute, one of the National Institutes of Health in Maryland.
The six-year study, published in the journal Archives of Ophthalmology, involved 4,519 people aged 60 to 80. The researchers took photographs of the patient's retinas to determine if they had AMD, and if so, to which of four stages the condition had progressed.
The participants also completed a food frequency questionnaire that measured how often they consumed foods rich in certain vitamins, minerals and other nutrients. They were then divided into five groups based on the amount of each nutrient they consumed.
The researchers found that those in the top fifth of dietary consumption of foods containing lutein and zeaxanthin had a 35 per cent lowered risk of developing AMD, compared to those in the lowest fifth of consumption.
The researchers think carotenoids protect vision by allowing the eyes to filter harmful short-wavelength light and by curtailing other damaging effects to the macula, or the center of the eye's retina.
Foods considered good sources of the nutrients include dark leafy greens, sweet potatoes, peas, Brussels sprouts and eggs.
"If these cross-sectional results can be confirmed... lutein and zeaxanthin may be considered as useful agents in food or supplement-based interventions designed to reduce the risk of AMD," the authors conclude.
