Nitric Oxide: What to Know

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Nitric Oxide: What to Know

The words “nitric oxide” may conjure up not-so-fond memories of high school chemistry class. But before your eyes start to glaze over, you might be interested to know that nitric oxide plays some pretty impressive roles in the body. Also, people with type 1 or type 2 diabetes have an impaired ability to generate nitric oxide in the body, which has implications for heart health.

What is nitric oxide?

Nitric oxide is a gas that is made up of one atom of nitrogen and one atom of oxygen. Known in scientific circles by its formula “NO,” nitric oxide is made from L-arginine, an amino acid. L-arginine is the only amino acid that makes a sufficient amount of NO. Interestingly, NO can be generated by some foods, including certain vegetables, such as beets, fruits, chocolate, red wine, and high-protein foods that contain arginine. By the way, NO is not the same as nitrous oxide, otherwise known as “laughing gas” that is often used in the dentist’s office.

As you’ll see, NO is important for health — particularly heart health — but it can also be extremely toxic. From an industrial standpoint, NO emissions are generated by fossil fuel power stations and motor vehicles. Exposure to NO can be irritating to the skin, eyes, and mucous membranes and can lead to serious breathing problems. Even within the body, NO, while essential for health, can also be extremely damaging to cells.

What does nitric oxide do?

NO wears many hats in the body, including:

  • Relaxing blood vessels and keeping them flexible
  • Acting as a neurotransmitter, or chemical messenger in the brain
  • Supporting the immune system to defend against bacteria and cancer cells

How does nitric oxide support a healthy heart and blood vessels?

NO works to keep blood vessels healthy and flexible so that they can do their job of sending blood and oxygen to cells and tissues. Flexible, relaxed blood vessels also mean better blood pressure control.

In addition, NO prevents platelets and white blood cells from sticking to the lining of blood vessels, lessening the buildup of plaque, a substance that can cause blood clots and blockages.

On a side note, if you take nitroglycerine for chest pain, this drug turns into NO, improving blood flow and oxygen to the heart. Statins and ACE inhibitors also increase the availability of NO.

What is the role of nitric oxide in erectile dysfunction?

If you take the “little blue pill,” also known as Viagra (sildenafil), or other medications for erectile dysfunction, know that these medications target NO, which relaxes blood vessels and smooth muscle in the penis, which are needed to obtain and sustain an erection. There’s also a link between men who have erectile dysfunction and an increased risk of heart disease.

How does nitric oxide impact the brain?

NO is a chemical messenger, or neurotransmitter. If NO production is reduced, it can decrease blood flow to the brain and may lead to cognitive problems. Interestingly, NO is thought to play a role in either the prevention or the progression of Alzheimer’s disease, and researchers are working on determining whether NO is “neuroprotective” or “neurotoxic” when it comes to this disease.

NO can help to reduce pain in two ways: by increasing cGMP (which is how opioids work) and by increasing circulation that “reduces pressure on nerves due to localized edema,” writes Thomas Burke, PhD, on the website Diabetes in Control.

In terms of other nervous system diseases and even mental health disorders such as depression, understanding how NO works can open up new treatments for these conditions.

How does nitric oxide affect cancer?

As with brain health, NO is viewed as a “double-edged sword” when it comes to cancer, according to the Berkeley Wellness website. On the one hand, NO can cause “apoptosis” of cancer cells, which is when cancer cells destroy themselves (that’s a good thing). But on the other hand, NO can promote “angiogenesis,” which is the growth of blood vessels that support cancer cells.

Does diabetes affect nitric oxide?

Research shows that people with diabetes have a reduced ability to produce nitric oxide. This may, in part, explain the increased risk of high blood pressure and heart disease in those with diabetes. Also, it’s thought that high blood sugar levels lead to more binding of glucose to hemoglobin, and that, in turn limits the release of NO to help maintain blood flow.

Nitric oxide and COVID-19

Fortunately, more and more people are getting the COVID-19 vaccine, but not everybody has had the opportunity to get vaccinated at this the point; others are unable or unwilling to get the vaccine. Researchers believe that NO could be a possible treatment for COVID-19 by helping to improve the oxygenation of blood and by working as an antiviral agent (other studies show that NO is helpful against other viruses, such as the herpes virus and coxsackievirus, a virus that can cause hand, foot and, mouth disease as well as disease of the lungs, heart, and muscles).

Want to learn more about nitric oxide? See our “Nitric Oxide: Definition and Overview.”

Amy Campbell, MS, RD, LDN, CDCES

Amy Campbell, MS, RD, LDN, CDCES

Amy Campbell, MS, RD, LDN, CDCES on social media

A Registered Dietitian and Certified Diabetes Educator at Good Measures, LLC, where she is a CDE manager for a virtual diabetes program. Campbell is the author of Staying Healthy with Diabetes: Nutrition & Meal Planning, a co-author of 16 Myths of a Diabetic Diet, and has written for  publications including Diabetes Self-Management, Diabetes Spectrum, Clinical Diabetes, the Diabetes Research & Wellness Foundation’s newsletter,, and

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