The vegetables reduce the risk for the most common type of glaucoma—primary open-angle glaucoma (POAG)—by up to 30 per cent, say researchers from Harvard Medical School. They say that the nitrate in the vegetables gives them their protective effect.
POAG is the result of poor blood flow to the eyes, which can damage the optic nerves. It affects 1 to 2 per cent of the general population, and around 5 per cent of people aged 80 and older.
People who ate the highest amounts of vegetables a day—which amounted to 240 mg of dietary nitrate—had the lowest risk of developing glaucoma, they found. The average risk reduction was between 20 and 30 per cent, and was as high as 50 per cent for a special type of glaucoma known as early paracentral visual loss.
They based their discovery on an analysis of the Nurses’ Health Study, which involved 63,893 women, and the Health Professionals Follow-up Study, in which 41,094 men participated.