The Role of Nitric Oxide in Healthy Immune Function
COVID-19, a new coronavirus strain that has reached a pandemic level, has the world at a standstill. This virus is highly contagious and potentially very dangerous for many. People who contract the virus may remain asymptomatic, while many experience severe symptoms that quickly become deadly for some.
It’s more important than ever to support your immune system and protect yourself from the risks of contracting COVID-19. One way is to optimize your body’s ability to produce nitric oxide (NO), a key player in immune function.
Nitric oxide facilitates the immune response starting with blood flow
NO production in the body plays a huge role in circulation and blood flow. Your circulatory system serves as a transportation system for important immune cells, and adequate blood flow is crucial for your immune system to work efficiently. Poor circulation makes it more difficult for immune cells to target and kill viruses and bacteria that are attacking the body, giving the disease more time to replicate and spread.
NO improves blood flow by helping to relax the smooth muscle that lines blood vessels and arteries. When this muscle relaxes, blood flow may increase.
Nitric oxide restores oxygen homeostasis
When a patient is critically ill, they commonly experience hypoxia, or lack of oxygen in the cells. This environment benefits COVID-19 specifically, promoting rapid reproduction of the virus.
Hypoxia triggers NO production to improve blood flow and move more oxygen into the cells. When oxygen reaches the cells, homeostasis is restored and the transcription factor responsible for replicating COVID-19 is deactivated. In other words, oxygen homeostasis slows the progression of the disease.
However, people with chronic illness may experience oxidative stress that inhibits NO production and therefore inhibits oxygen from getting to the cells efficiently.
Nitric oxide works alongside immune cells
NO actually helps other immune cells kill viruses and bacteria. When the immune system detects a pathogen, it activates nitric oxide production through the L-arginine pathway. This pathway depends on inducible nitric oxide synthase (iNOS), an enzyme. This pathway produces nitric oxide used to improve blood flow and target pathogens.
NO may also protect against coronavirus specifically. In fact, after the SARS outbreak in 2003, scientists found that NO was a strong antiviral against the virus. The current coronavirus is actually a 79% match to the 2003 virus, meaning NO may offer a similar effect in the current outbreak.
Researchers are looking further into this theory to help with the current virus. In fact, scientists in China launched a clinical trial in March to evaluate how NO may slow the progression of COVID-19.
Conditions for NO production directly affects the immune system
If there is not enough iNOS present, the body will compensate with inflammation. This decreases the body’s ability to stop viral replication, meaning the virus will spread and continue to attack the body.
Furthermore, the NOS must be in a coupled state for the pathway to work. This is a problem for older patients, because NOS becomes more commonly uncoupled for people over the age of 40. In fact, NO production can decrease by as much as 50% by this age. NO production may decrease even further for those also dealing with oxidative stress and chronic diseases such as diabetes, cardiovascular disease or hypertension.
Dietary nitrates can increase NO production
Dietary nitrates can be converted to nitric oxide, without depending on the NOS enzyme. However, nitrates also help recouple NOS and therefore boost NOS enzyme activity and the immune system.
To increase dietary NO activity and production, eat plenty of foods like:
- Raw beets
- Bok Choy
- Citrus fruits
- Dark chocolate
All of these foods have components that boost NO production, boost NO activity, or protect NO against oxidative stress. For example, raw beets and leafy greens like spinach or arugula are high in nitrates that directly convert to NO without needing the additional NOS enzyme.