 A principal source of dietary inorganic nitrate, which is reduced to nitric oxide in the body, is from leafy green vegetables.The blood pressure lowering effects of leafy green vegetables, in particular, spinach and arugula, are abundant in anti-hypertensive diets such as the DASH diet.Several papers have shown saliva nitrite levels correlate with blood nitrite levels which both serve as meaningful surrogates for blood pressure lowering effects.