As we grow older, our cells lose the ability to make adequate amounts of NO. Therefore, dietary inorganic prebiotic nitrates, found in many vegetables, become a critical source. Prebiotic nitrates are absorbed in the gut and circulate to the saliva glands where they are released into the mouth. Upon release, nitrate is converted to nitrite by the friendly nitrate-reducing bacteria living on the back of the tongue. The nitrite is subsequently swallowed and further reduced in the gut and circulation to nitric oxide to exert its health benefits.

Beets and leafy greens, including spinach, arugula, rhubarb, chard, kale, are rich in inorganic prebiotic nitrate. The consumption of leafy greens and other potassium nitrate–rich vegetables, are the primary source of inorganic prebiotic nitrate found in the Mediterranean, DASH and MIND diet, and the traditional Japanese diet. All of these diets have been shown to exhibit nitric oxide-mediated effects in various clinical studies demonstrating improvement of vascular wellness.

Similar to our gut, our mouths contain a mix of good and bad bacteria. Having a 'good microflora' on our tongue that converts dietary prebiotic nitrate to nitrite is critical in restoring vascular health. Eradication of oral nitrate-reducing bacteria through antiseptic mouthwash, such as chorhexidine, or overuse of antibiotics can result in cardiometabolic problems. Studies have also found that periodic tongue brushing may provoke the growth of these healthy nitrate-reducing bacteria. Others have found that increased dietary intake of inorganic nitrate shifted the oral microflora to a richer population of nitrate-reducing bacteria with improvements in cardiovascular wellness.