Nitric oxide (NO) an important helper in the body

Nitric oxide is usually known as a harmful environmental pollutant from car exhaust and industry. It's a reactive gas that, at high concentrations, can damage the airways and reduce oxygen transport in the body. But nitric oxide also plays a very important and helpful role in our bodies.

High blood pressure, among other things, damages the innermost layer of the blood vessels the endothelium. The endothelium has important tasks in regulating blood pressure because it influences vessel tone. That means it helps determine whether a vessel is constricted and less elastic or relaxed and elastic. Part of this process comes from one of the endothelium's functions: it helps produce the body's own nitric oxide (NO).

Besides its relaxing, so-called vasodilatory effect on the blood vessels, NO has other important roles in the body. For example, it inhibits platelet aggregation, so it prevents blood platelets from clumping together and forming clots. On the surface of the endothelium it reduces the formation of certain molecules that allow white blood cells (leukocytes) to stick the first step in atherosclerosis. NO also reduces the formation of free radicals and the oxidation of fats, which both contribute to atherosclerosis. In addition, it has an anti-inflammatory effect in the body.

For the blood vessels this is beneficial in several ways: it relaxes and widens the vessels, counteracts the development of atherosclerosis that narrows the vessel, and has anti-inflammatory effects. Inflammation would, in turn, lead to further narrowing of the vessel. It also reduces the formation of blood clots that could get stuck in narrow spots and cause a blockage.

Where does the useful NO in the body come from?

The body produces NO in the endothelial cells that line the inside of the blood vessels. For this it needs an enzyme called NO synthase, which combines the nitrogen-containing amino acid arginine with oxygen. The arginine molecule then releases NO; the remainder of the molecule is further processed. The "raw material" arginine is also produced by the body at least when we're younger.

But immune cells the macrophages can also produce NO to fight bacteria.

In the paranasal sinuses, NO is produced in larger amounts and then inhaled with the breath especially when breathing through the nose. This lowers vascular resistance in the lungs and improves oxygen uptake. There is evidence suggesting that the increased NO production in the sinuses is a defense mechanism against bacteria and viruses.

Unfortunately, the body's NO production decreases with age. This is partly due to reduced arginine production in the body. Arginine can, however, be supplied relatively easily through food. Sunflower seeds, nuts and legumes are, for example, good sources of arginine. The endothelium itself also ages and loses some of its functional capacity.
A study published in 2025 showed that older people responded better than younger ones to drinking nitrate-rich beetroot juice; the blood pressure of these participants fell. This is attributed to changes in the oral flora caused by the juice. Those changes were also found in younger study participants, but they did not lead to lower blood pressure in that group possibly because their blood pressure was already in the normal range.

NO precursors, such as inorganic nitrate, can also be taken in with food. In the body these are first converted to nitrite, from which the body can then produce NO in further steps. A well-researched and blood-pressurebeneficial source of these precursors is beetroot especially as juice. Other vegetables (particularly leafy greens) also contain these important substances.

The following image shows how this conversion takes place in the body:

Because the converted NO is ultimately available again in the salivary glands, it can be inhaled with each breath. Studies showed that after drinking 500 ml of beetroot juice, the nitric oxide level in the exhaled air of COPD patients was more than 200 percent higher than before drinking the beverage.

Organic Beetroot Juice R³benherz

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Sources:

This article comes from BloodPressureDB – the leading app since 2011 that helps hundreds of thousands of people monitor their blood pressure every day. Our content is based on carefully researched, evidence-based information and is continuously updated (as of 02/2026).

Author Sabine Croci is a certified medical assistant with many years of experience in internal medicine and cardiology practices as well as in outpatient care. Since 2015 she has led the editorial team at BloodPressureDB. With additional qualifications as a paramedic, first responder, and training in various therapy and emergency areas, she provides well-founded, practical, and reliably reviewed information.

Nitric oxide (NO) an important helper in the body

Where does the useful NO in the body come from?

Organic Beetroot Juice R³benherz

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