Dark Green Leafy Vegetables

The darker the vegetables, the richer they are in the carotenoid lutein and dietary nitrate. Research suggests that lutein is important for ocular (related to the eyes) and cognitive health. Dietary nitrate has been shown to improve cardiovascular health.

How they work

Lutein is an anti-oxidant that concentrates in the macula of your eye and absorbs damaging UV light. The concentrations of lutein and zeaxanthin (a related carotenoid) are 500-fold higher in the macula than in other parts of your body. Lutein is also taken up by your brain, where it decreases oxidative stress and activates protective anti-inflammatory pathways. 

Nitrate from vegetables is converted to nitrite and then to nitric oxide inside the body, which makes your blood vessels relax and prevents them from stiffening with age, resulting in better blood pressure control. It also inhibits your platelets from clumping together and causing blood clots.

How much to have

Include at least ½–1 cup of cooked dark green leafy vegetables or a large raw salad of dark leaves each day. Dark leafy greens contain significantly more nutrients than other green vegetables. For example, per serving, kale contains 11 times more lutein than broccoli.

You can eat these vegetables fresh or cooked (lutein is stable with boiling), or drink them in smoothies. They are particularly important for people who have prediabetes, diabetes or eyesight and memory problems or who are at risk for heart disease or stroke.