Glaucoma is a serious eye condition that usually develops when fluid increases in the front part of the eye and causes pressure, damaging the optic nerve that leads to loss of vision. New research now suggests that eating green leafy vegetables daily may decrease the risk of glaucoma by 20 percent or more over many years.
Researchers at the Harvard Medical School in Boston, USA, followed nearly 64,000 participants from 1984 through 2012 in one study, and, in another study, they tracked 41,000 participants from 1986 through 2014. The men and women were all 40 or older. None had glaucoma at the start of the study, and they had eye exams every two years.
Over the 25-year follow up, almost 1,500 people developed glaucoma. The researchers looked at the consumption of green leafy vegetables among the participants.The investigators divided the participants into five groups, from the highest level of leafy green vegetable consumption to the lowest. Those who ate the most averaged about 1.5 servings a day, or about one and a half cups a day. Those in the group eating the least leafy greens ate about a serving every three days.
Researchers foundthat those consuming the most green leafy vegetables had a 20 to 30 percent lower risk of glaucoma. “In glaucoma, there is an impairment of blood flow to the optic nerve. And an important factor that regulates blood flow to the eye is a substance called nitric oxide. Green leafy vegetables contain nitrates, which are precursors to nitric oxide,” the researchers said. However, they warned the study did not prove cause-and-effect and needed further investigation.