Next time you’re in the grocery store, keep your eyes peeled for leafy greens like arugula, spinach, and lettuce—they could help save your eyesight. Researchers have found that a high intake of dietary nitrates, which are abundant in leafy greens and some other vegetables, may reduce the risk of primary open-angle glaucoma (POAG). POAG is the most common form of glaucoma in the US, and occurs when fluid builds up in the eye, damaging the optic nerves and causing vision loss that usually begins at the outer edges of the visual field. The study was published in JAMA Ophthalmology and used data from 63,893 female participants from the Nurses’ Health Study (1984–2012) and 41,094 male participants from the Health Professionals Follow-up Study (1986–2012). The participants were all 40 or older and free of POAG when they enrolled in the study. Over an average of 16 years, researchers determined the participants’ dietary nitrate intake via questionnaires and monitored their medical records for new cases of POAG. By the end of the study, researchers found that 1,483 participants had developed POAG, and participants who ate more nitrates were less likely to have developed the condition. Specifically:

• Those who ate the most nitrates (about 240 mg per day) were 21% less likely to develop POAG than those who ate the least nitrates (about 80 mg per day).
• About 57% of these nitrates came from leafy greens: In fact, consuming 1.45 or more servings of leafy greens per day was associated with an 18% reduced risk of POAG compared with consuming 0.31 servings per day.

This is not the first time leafy greens have been tied to eye health: One previous study found that a high dietary intake of carotenoids, also found in green vegetables like spinach and kale, may reduce the risk of macular degeneration in older men. So, grab a big green salad full of arugula and spinach for lunch to help your eyesight stay clear.

Source: JAMA Ophthalmology