What’s the difference between people who contract the COVID virus and have either a mild respiratory illness or no symptoms at all and those who need to be hospitalized and develop multiple organ failures? One Korean researcher has recently reviewed accumulating evidence pointing to poor gut health as a possible explanation.
Professor Heenam Stanley Kim of Korea University cites recent studies showing that those patients who go on to develop severe COVID—the elderly and those with certain chronic health conditions—have one thing in common: they are both likely to have altered gut bacteria (a lack of bacterial diversity and an unfavorable ratio of harmful to beneficial bacteria—a situation called “gut dysbiosis”) and a “leaky gut.”
A healthy gut has a lining composed of cells tightly packed together (called “tight junctures”) and a thick layer of mucous. Such a lining allows only beneficial substances to pass through the gut wall into the bloodstream. The rest gets excreted.
But certain conditions, primarily gut dysbiosis, can cause the mucous layer to thin out and the “tight junctions” to become leaky. This creates a diseased condition in which undigested food particles as well as pathogens and toxic by-products pass through holes in the gut out into the bloodstream.
COVID starts out as a respiratory infection. If the host’s immune defenses are strong in the lungs, it may go no further. But if immune defenses in the lungs are insufficient, Kim suggests the virus’s next stop is the gut. About 70% of all the body’s immune cells are located in the gut, and in a healthy gut, these immune cells are supported by a mighty army of friendly bacteria.
But if the gut is suffering from gut dysbiosis, it can’t put up much of a defense. In that case the virus causes gastrointestinal symptoms like nausea, vomiting and diarrhea. And if the gut is also leaky, the virus gets out into systemic circulation where it can invade the liver, kidneys, heart, spleen, brain and/or bone marrow, leading to multiple organ failure.
It might seem that the lesson here is to keep respiratory immunity strong while strengthening gut immunity as a back-up. But good gut health has a systemic effect on the entire immune system; so anything you do to strengthen gut health will benefit immunity throughout your body including in the respiratory tract.
Unfortunately many features of modern life have negatively impacted gut health. A healthy ratio of good to bad colonic bacteria, for example, is 85:15. However experts have said that in most Americans that ratio is reversed!
A major reason for pervasive gut dysbiosis is our low-fiber diets. Fiber feeds gut bacteria, and Kim specifically recommends increasing fiber as a way to improve gut health.
But there are many other factors involved in building and maintaining optimal gut health, and we will talk about these in our next Newsclip.
- Kim HS. Do an altered gut microbiota and an associated leaky gut affect COVID-19 severity? mBio: an Open Access Journal Published by the American Society for Microbiology. January-February 2021; 12(1): e03022-20. Published online January 12, 2021.
- “Dys” means ill or bad; “biosis” refers to life, so “dysbiosis” means “bad life”—the bad bacteria have taken over the neighborhood and there’s bad life inside your gut.
- Other factors that cause leaky gut include refined gluten grains and, many times more destructive, glyphosate, the herbicide used on most genetically modified foods.