SYDNEY — Want to maintain strong, healthy vision as you age? Eat more salad. A new study conducted by Australian researchers finds that eating more leafy greens — such as lettuce, spinach, or kale — may help prevent macular degeneration, a condition that causes loss in the center of the field of vision.
There are two main types of macular degeneration, wet and dry, both relating to the deterioration of the retina. Wet macular degeneration occurs when blood vessels grow under the retina and leak fluids. Dry macular degeneration occurs when the center of the retina itself deteriorates. The disease, which is incurable, is most likely to occur in people over 50.
Researchers from the Westmead Institute for Medical Research investigated the link between vegetable nitrates, found mainly in leafy greens and beetroot, and early-stage, age-related macular degeneration (AMD). They interviewed more than 2,000 Australian adults over the age of 49 and followed them over a 15-year period, which ended between 2007 and 2009. Participants disclosed the contents of their diets in questionnaires and retinal photographs were taken to check for AMD.
The study findings revealed that individuals who ate between 100 and 142 milligrams of vegetable nitrates every day had a 35 percent lower risk of developing AMD than those who ate less than 69 mgs of vegetable nitrates each day.
“This is the first time the effects of dietary nitrates on macular degeneration risk has been measured,” says lead researcher Bamini Gopinath in a release. “If our findings are confirmed, incorporating a range of foods rich in dietary nitrates – like green leafy vegetables and beetroot – could be a simple strategy to reduce the risk of early macular degeneration.”
The authors found no added benefits from participants who consumed more than 142 milligrams of vegetable nitrates daily, nor did they find a link to late-stage AMD.
For reference, spinach has about 20 mg of vegetable nitrate per 100 grams and beetroot has about 15 mg of nitrate per 100 grams.
The full study was published online on October 17, 2018 in the Journal of the Academy of Nutrition and Dietetics.