A new study published in JAMA Ophthalmology found that individuals with a diet high in nitrates, which is found in leafy green vegetables such as kale or spinach, had a reduced risk of primary open-angle glaucoma by between 20 to 30%.

Previous research has shown that nitric oxide is a potent factor in lowering intraocular pressure, and leafy greens are an important source of the nitrates and nitrites that get converted into nitric oxide in the body.

The researchers from Harvard School of Public Health used data collected from 1984-2012 from the Nurses’ Health Study (64,000 women) and the Health Professionals Follow-up Study (41,000 men) which were all 40 years or older and free of POAG when the study began. 1,483 incidents of POAG developed over the course of the study. The researchers found that the group with the highest dietary nitrate intake (240 mg/day or 1.76 servings of leafy greens/day) had a 20 to 30% reduction in POAG and a 40 to 50% reduction in POAG with early paracentral VF loss compared to the group with the lowest dietary nitrate intake (80 mg/day or 0.31 servings/day).

The researchers caution that this study had limitations, such as relying on questionnaires to ascertain diet and having a 90% white population, however, “These results, if confirmed in observational and intervention studies, could have important public health implications,” the authors write.

Further Information: http://archopht.jamanetwork.com/article.aspx?articleid=2480455