A rich source of inorganic nitrate in the human diets come from leafy green foods, such as spinach and arugula.  (inorganic nitrate) is the viable active component within beetroot juice and other vegetables. Drinking water is also a dietary source.
Dietary nitrate supplementation delivers positive results when testing endurance exercise performance.
Ingestion of large doses of nitrate either in the form of pure sodium nitrate or beetroot juice in young healthy individuals rapidly increases plasma nitrate concentration by a factor of 2 to 3, and this elevated nitrate concentration can be maintained for at least 2 weeks. Increased plasma nitrate stimulates the production of nitric oxide, NO. Nitric oxide is an important physiological signaling molecule that is used in, among other things, regulation of muscle blood flow and mitochondrial respiration.