'I'm an Infectious Disease Expert, and This Is the Most Commonly Overlooked COVID Symptom Right Now'

By now, you know that the most common COVID-19 symptoms are respiratory: Coughing, sore throat, congestion, shortness of breath, plus fatigue, headache, muscle aches and fever. However, infectious disease experts warn that a lot of us are overlooking another major COVID-19 symptom, and it ain't pretty: it's an upset stomach.

As it turns out, although they're typically overlooked, gastrointestinal COVID-19 symptoms aren't as uncommon as you might think—you just may not hear about them as often as others.

"Previous research indicates that approximately one in five people who tested positive for COVID-19 reported at least one gastrointestinal symptom," Dr. Syra Madad, DHSC, MSc, MCP, CHEP, infectious disease epidemiologist at Harvard's Belfer Center for Science and International Affairs and chief bio preparedness officer at NYC Health + Hospitals, tells Parade.

Among those gastrointestinal symptoms, the most common one is loss of appetite.

This occurs for several reasons, according to infectious disease experts and gastroenterologists who spoke with Parade: If you lose your sense of smell and taste when you get a COVID infection, you're less likely to want to eat because you can't enjoy it as much—and you may also have other gastrointestinal symptoms that also make eating seem unappealing. These symptoms can include diarrhea (the second most common GI symptom, per experts), constipation, abdominal pain, nausea and vomiting. None of them are fun, so before we go any further: You can potentially prevent all of them from getting serious by getting your current COVID-19 booster.

Related: The One Unexpected Thing Infectious Disease Experts Are Begging You to Stop Doing if You Don't Want to Get COVID This Summer

How Do I Know My Gastrointestinal Symptoms Are from COVID-19?

Because anything from food-borne illnesses to too much tequila can cause similar gastrointestinal symptoms as COVID-19, experts say frequent testing is key, especially if you're showing symptoms actively or were recently exposed to the virus.

"It can be tricky to tell the difference because gastrointestinal symptoms like diarrhea, nausea and vomiting are common in many illnesses, including food poisoning and stomach bugs," Dr. Adam Booth, MD, FCAP, FASCP, assistant professor of pathology and immunology at Washington University School of Medicine and member of the College of American Pathologists, explains. "However, if these symptoms are accompanied by other COVID-19 signs such as a cough, fever, fatigue, muscle aches, or a loss of taste and smell, it could indicate a COVID-19 infection. Additionally, if you have been in contact with someone who has tested positive for COVID-19 or if there's an outbreak in your community, it's more likely that your symptoms could be related to COVID-19."

Dr. Booth adds, "Getting tested not only helps you in receiving the right treatment but also in preventing the spread of the virus to others."

"Abrupt onset of vomiting is a hallmark symptom of norovirus, one of the most common viruses causing food poisoning," Dr. Scott Roberts, MD, assistant professor and associate medical director of infection prevention at Yale School of Medicine, tells Parade. "Usually this is quick and self-limited; most people recover in one to two days. Fever, fatigue and weakness can be seen in both norovirus and COVID-19 and does not help distinguish them easily."

Related: COVID Is Surging Right Now—This Is the #1 Symptom to Look Out For, According to Infectious Disease Experts

Can Long COVID May Cause Gastrointestinal Issues?

As if long COVID wasn't bad enough already, you can include gastrointestinal symptoms as some that may pop up for a while time after your initial infection.

"Gastrointestinal problems have also been noted to manifest themselves up to a year post-COVID-19 and is noted to be among numerous manifestations associated with long COVID," Dr. Zuri Dale, MWM, MPH, epidemiologist and data analyst at Texas Southern University notes.

Some of these issues can get potentially serious if they're not treated.

"In some cases, there can be damage to the lining of the gut that allows bacteria normally found in the lumen of the intestine to invade deeper in the gut tissues, this could lead to bacteria in the blood (bacteremia) or sepsis," Dr. Peter Hotez, MD, Ph.D., co-director of the Texas Children's Hospital Center for Vaccine Development and dean of the National School of Tropical Medicine at Baylor College of Medicine, points out. "There could also be disruptions to the normal gut flora or microbiome. Some of these symptoms can last for significant periods after the infection resolves and could be considered a form of long COVID."

Related: The Super Simple COVID Prevention Tip Most People Forget About, According to Infectious Disease Experts

What Should I Do if I Have Gastrointestinal COVID Symptoms?

If you have COVID-19 and it's giving you an upset stomach, check with your doctor to make sure whatever treatment you do doesn't interact badly with any prescriptions (like Paxlovid) you might be using to treat the disease overall. That said, experts say that you can generally treat it the way you would a bout of food poisoning or the like, barring any other issues or complications that your physician would point out to you.

"Stay hydrated with fluids and electrolytes," Dr. Samuel Sarmiento, MD, MPH, physician and contributor to Drugwatch, recommends. "Consume foods that are gentle on the stomach, monitor your symptoms and self-isolate if an infection has been confirmed."

You'll want to watch out for some specific foods and even some medicines, according to Dr. Pornchai "Dr. Lee" Leelasinjaroen, MD, gastroenterologist at GastroHealth in Kennewick, Washington.

"Avoid anything that is hard to digest and stays in the stomach and small bowel longer. This includes things like red meat, fatty or greasy food, sugary foods or drinks and dairy products," Dr. Lee explains. "High sugar content can worsen diarrhea. Until your GI symptoms resolve, you might want to avoid raw fruits and vegetables and things that might irritate the stomach like spicy food and NSAID medications."

If your symptoms linger or are severe, talk to your doctor and possibly a specialist for help.

"Patients with significant gastrointestinal symptoms from COVID should seek medical attention," Dr. Hotez advises. "If your GI symptoms are persistent, it may even warrant a visit to the gastroenterologist for inspection of the gut from the inside either through endoscopy or colonoscopy."

Next, What to Eat if You Have COVID-19

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