Examining the link between low serotonin and long COVID

PHOTO BY JOSHUA KODIS

Serotonin is a neurotransmitter that carries messages between nerve cells in the brain and the rest of your body. It plays a key role in mood, sleep, digestion, nausea, wound healing, bone health, blood clotting and sexual desire. Serotonin levels that are too low or too high can cause physical and psychological health problems.

We all have this neurotransmitter. But unfortunately, many people don’t have enough of it and more and more researchers and doctors are finding a connection between low levels of serotonin and long COVID symptoms.

Dr. Aisha Thomas, internal medicine and infectious disease specialist at Sebastian River Medical Center, says the symptoms of long COVID – such as chronic pain, brain fog, shortness of breath, chest pain and intense fatigue – can be debilitating, and she sees a clear connection between low serotonin levels and these symptoms.

Researchers at the University of Pennsylvania found in a recent study that reduction of serotonin in the body is triggered by remnants of the COVID virus lingering in the gut, where most serotonin is made. Depleted serotonin could explain memory problems and some neurological and cognitive symptoms of long COVID, they say.

The researchers determined that some patients had SARS-CoV-2 virus in their stool samples months after contracting an acute COVID-19 infection, suggesting that components of the virus remain in the gut of some patients long after the actual infection. The lingering virus, called a viral reservoir, triggers the immune system to release proteins called interferons that fight the virus. These interferons cause inflammation that reduces the absorption of the amino acid tryptophan in the gastrointestinal (GI) tract – and tryptophan is a building block for several neurotransmitters, including serotonin.

The researchers found that when tryptophan absorption is reduced by persistent viral inflammation, serotonin is depleted, which in turn can cause several of the symptoms associated with long COVID, such as memory loss.

Lori Jagniecki, infection control practitioner at Sebastian River Medical Center, says that since 90 percent of serotonin is made in the gut (the rest is made in the brain), when inflammation affects your gut, it produces greatly reduced levels of the neurotransmitter.

“Many instances of low serotonin are caused by people’s lifestyles and exist before they ever get COVID,” says Thomas. “You need to get enough sleep – approximately seven hours a night – bright sunlight, omega-3, prebiotics, probiotics, healthy foods.”

Jagniecki adds that vitamin B complex is another important addition to your health routine.

“Eat foods that increase your tryptophan – tuna, nuts, bananas. Protein-rich foods are important to your diet.”

The World Health Organization defines long COVID, also known as Post-COVID Conditions, as “the continuation or development of new symptoms three months after the initial SARS-CoV-2 infection, with these symptoms lasting for at least two months with no other explanation.”

The Centers for Disease Control and Prevention (CDC), which states that nearly 1 in 5 American adults who had COVID-19 experiences symptoms of long COVID, adds it includes a wide range of ongoing health problems that can last weeks, months or even years. The condition might appear to be an extension of the original COVID symptoms, or they may recur after the initial illness subsided, or they may be new symptoms that weren’t present during COVID. They can affect any part of the body and serious cases may affect multiple body systems, including the heart, lungs, kidneys, skin and brain.

Medical News Today reported that research on treating long COVID basically started from square one. “Unfortunately, prior to the pandemic, we had invested very little in understanding post-viral illnesses. We pretty much ignored this area completely.

Consequently, not much is known about the mechanisms of neurologic abnormalities that we see in people with flu and with COVID-19.”

Thomas says your gut can regenerate even if you were deficient before long COVID. “It will take some time – it didn’t happen in a day, and it won’t be fixed in a day. But every small change will help. You will be in a better place if there’s another pandemic and it will help you if you have a chronic disease,” says Thomas.

Besides improvements in lifestyle and diet, some researchers are exploring the possibilities of medicines to increase serotonin in the system.

“There is tremendous need for effective ways to treat long COVID, and clinical trials of several treatments are underway,” according to a recent article in the New York Times. “Dr. Christoph Thaiss, a lead author of the study and an assistant professor of microbiology at the Perelman School of Medicine at the University of Pennsylvania, and Maayan Levy, a lead author and assistant professor of microbiology at the Perelman School of Medicine, said levels of serotonin and other metabolites were altered right after a coronavirus infection, something that also happens immediately after other viral infections.”

The doctors said they would be starting a clinical trial to test fluoxetine, a selective serotonin reuptake inhibitor often marketed as Prozac, and possibly also tryptophan.

“If we supplement serotonin or prevent the degradation of serotonin, maybe we can restore some of the vagal signals and improve memory and cognition and so on,” Dr. Levy said.

Dr. Aisha Thomas, Internal Medicine and Infectious Disease specialist at Sebastian River Medical Center, received her medical degree from Spartan Health Sciences University, completed her residency at Wayne State University, and her fellowship at Medical University of South Carolina College of Medicine. Lori Jagniecki, RN, MPA, CIC, Infection control practitioner at Sebastian River Medical Center, is a graduate of Marymount University Nursing School in Arlington, Va., and has a master’s degree in healthcare administration from Western Michigan University. She is board certified in infection prevention and control.

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