• COVID-19 patients offer to suffer from gastrointestinal symptoms, as well as, or instead of, respiratory issues.
  • The molecules that the virus attacks in our bodies are present not just in our lungs but also in our gastrointestinal tract.

When we think of the symptoms of coronavirus, we think of the lungs – people on ventilators or with nasty coughs, struggling to breathe. That’s because a COVID-19-positive patient often presents with fever, persistent cough, muscle pain, and fatigue.

But the molecule that the virus attacks in our bodies – Angiotensin-Converting Enzyme 2 or ACE2 – is present not just in our lungs but also in our gastrointestinal tract. This could be behind the significant number of cases in which patients show gastrointestinal symptoms such as diarrhea, nausea, and vomiting.

A recent commentary in Gut, a British Medical Journal publication, highlighted evidence from China. It showed that if a patient presents with gastrointestinal issues, like diarrhea, nausea, and vomiting, more than a quarter of them may not have respiratory symptoms.

Unlike previous work, which had shown that less than 4% of COVID-19 patients had gastrointestinal symptoms, this study put the rate at 11%. Others have suggested that the rate may be as high as 60%.

In these small studies, the researchers also linked patients with gastrointestinal presentations to poorer outcomes. When they compared them to those without gastrointestinal symptoms, patients had more severe disease, higher fevers, and a greater risk of liver injury.

In a separate study of those with a mild form of COVID-19, researchers compared those with gastrointestinal or respiratory symptoms, or both, with those presenting only with respiratory symptoms. They found that 23% of patients had gastrointestinal presentations alone, while 57% had both a gut and a respiratory illness. It also took longer for those with digestive symptoms to clear the virus.

Gut invaders

Interestingly, the first case of novel coronavirus reported in the US had two days of nausea, vomiting, and diarrhea in addition to their respiratory symptoms. The virus was detected in this patient’s nose and throat samples and isolated from collected stool samples.

Analyzing specimens taken from the gastrointestinal tract of 95 COVID-19 patients has identified the virus in the esophagus, stomach, duodenum, and rectum. The virus also showed up in about half of the stool samples collected.

The suggestion is that the gastrointestinal symptoms are caused by the virus invading the ACE2-containing cells found throughout the bowel. This, together with the virus in the stool, suggests the gastrointestinal tract as another possible route of infection and transmission.

It appears that SARS-CoV-2 is detectable in the stool for several days after it has cleared from respiratory tract samples. So, patients who have recovered from COVID-19 or are asymptomatic could be shedding the virus into their stool without knowing it, potentially increasing the risk of transmission to others.

Why your microbiome matters

Why do symptoms in your gut mean you might get a worse case of COVID-19? Likely, the composition of your microbiome – the millions of bacteria and other organisms that usually live in our gastrointestinal tract – is critical to how an individual responds to COVID-19.

One group of researchers created a risk score based on biomarkers in the blood that can be increased or decreased depending on the composition of your microbiome. They found that the higher the score, the worse the outcome from COVID-19. This association was stronger for older individuals. The health of our gut bacteria has a critical role in how our immune system reacts to the disease.

So, it’s essential to maintain a healthy microbiome to fight COVID-19.

How do you do that? The key is to eat to feed your microbiome. Eating plant-based food you cook yourself and limiting ultra-processed and takeaway foods are to be commended while supplementing your diet with natural probiotics such as kombucha, kimchi, and natural yogurt. This will optimize your microbiome, not just for COVID-19 but also for your long-term health.

Gut feeling

With the pandemic continuing, we should all pay more attention to our guts. Much of the focus has been on ventilators, intensive care, and the respiratory consequences of the novel coronavirus infection. However, if you have new onset sickness, vomiting, diarrhea, and no other explanation, it may be COVID-19, and you may need help.

And suppose it’s true that the gastrointestinal tract is another source for virus transmission in both symptomatic and asymptomatic individuals. In that case, it remains paramount that people follow the advice to stay home and stay safe with shielding, social distancing, and regular hand-washing.

Finally, it is worth considering how to maintain a healthy microbiome in these challenging and unprecedented times – eating well may make a difference to your COVID-19 outcome.