Eating This Daily May Decrease Glaucoma Risk
Risk of the eye disease dropped by 20 percent or more for those who consumed the most, study found
By Kathleen Doheny
THURSDAY, Jan. 14, 2016 (HealthDay News) -- Eating green leafy vegetables daily may decrease the risk of glaucoma -- a serious eye disease -- by 20 percent or more over many years, a new study suggests.
"We found those consuming the most green leafy vegetables had a 20 to 30 percent lower risk of glaucoma," said study leader Jae Kang. Kang is an assistant professor of medicine at Brigham and Women's Hospital and Harvard Medical School in Boston.
Glaucoma is an eye condition that usually develops when fluid increases in the front part of the eye and causes pressure, damaging the optic nerve. It can lead to loss of vision, according to the U.S. National Eye Institute.
Although the study found an association between eating more leafy greens and a lower risk of glaucoma, it didn't prove cause-and-effect.
Kang's team followed nearly 64,000 participants in the Nurses' Health Study from 1984 through 2012, and more than 41,000 participants in the Health Professionals Follow-up Study 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, Kang said. Those in the group eating the least leafy greens ate about a serving every three days, according to Kang.
What is it about leafy greens that may help eye health?
"In glaucoma, we think there is an impairment of blood flow to the optic nerve," Kang said. "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.