Monkey Business Images/Shutterstock“All disease begins in the gut,” Hippocrates, the father of modern medicine, once said. That was 2,000 years ago, and perhaps a bit of an exaggeration (because not all disease can be said to begin in the gut; for example, genetic diseases begin in the genes). However, the science supporting the notion that the gut microbiome (the entire universe of microbes—both good and bad organisms that live in the gut) is linked with overall health, including susceptibility or resistance to various diseases, has grown dramatically in the last few years.
Even without thinking about the microbes that live in our gut, we know as a matter of science, anecdote, and intuition, that certain foods boost our immune systems. But an exciting new study out of the Medical School at Washington University in St. Louis has identified exactly how it is that at least one of the microbes that lives in our guts uses certain foods we eat in order to boost our immunity. Specifically, the study, which was published this month in the journal, Science, found that one particular gut microbe (Clostridium orbiscindens) actually prevented severe flu infections in mice, most likely by breaking down compounds called flavonoids that are commonly found in certain foods, including black tea, red wine, and blueberries.
The researchers alredy knew that these compounds have immune-boosting properties. They also knew that the gut microbiome is important in protecting against influenza, which is a common infection of the upper respiratory tract that can cause serious and even deadly complications in older adults, pregnant women, young children, and people with certain chronic health problems such as asthma and heart disease. So their aim was to isolate and screen human gut microbes to find one that actually metabolized flavonoids. The one that they found, Clostridium orbiscindens, does so to produce a metabolite that enhances interferon signaling (interferon signaling aids the body’s immune response).
“The metabolite is called desaminotyrosine, otherwise known as DAT,” said first author Ashley M. Steed, MD, PhD in a publication from the Medical School. “When we gave DAT to mice and then infected them with influenza, the mice experienced far less lung damage than mice not treated with DAT.” In other words, the immune response did not prevent, but minimized the damage the virus caused, and this is very important considering that the influenza virus is constantly changing, and not all infections can be prevented through vaccination.
“Next steps include identifying other gut microbes that also may use flavonoids to influence the immune system,” according to the aforementioned publication, as reported by Eurekalert. In addition, it will be useful to explore ways of boosting levels of bacteria in people whose intestines aren’t adequately colonized by Clostridium orbiscindens.
In the meantime, the authors suggest “it might not be a bad idea to drink black tea and eat foods rich in flavonoids before the next flu season begins.” And here are some ways that doctors avoid catching colds and flu. Already sick? Here’s how you can tell the difference between a cold and the flu.