Researchers at Washington University have discovered a gut microbe helped prevent the infection in mice by breaking down naturally occurring compounds called flavonoids, found in black tea, red wine and blueberries.
First author Ashley Steed, an instructor in paediatrics, said: “For years, flavonoids have been thought to have protective properties that help regulate the immune system to fight infections.
Older adults, pregnant women, young children and people with common health problems are particularly prone to serious complications caused by the flu.
Previous research has suggested that the gut microbe might help prevent the flu, but Ashley and her team wanted to identify which microbe it was.
As part of the study, the researchers screened human gut microbes looking for one that metabolised flavonoids.
HEART BREAKER Your risk of suffering a heart attack is ’17 TIMES higher the week after suffering FLU’
They discovered the microbe called clostridium orbiscindens helps break down flavonoids.
“Flavonoids are common in our diets, so an important implication of our study is that it’s possible flavonoids work with gut microbes to protect us from flu and other viral infections.
“Obviously, we need to learn more, but our results are intriguing.”
The flu, or influenza, is characterised by a fever, cough and body aches.
It is a common and sometimes deadly infection of the upper respiratory tract.
Ashley added: “The metabolite is called desaminotyrosine, otherwise known as DAT.
“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.”
Although the lungs of the mice treated with DAT didn’t have as much damage, their levels of infection were identical to the mice that weren’t treated with DAT.
Thaddeus Stappenbeck, a professor of pathology and immunology, said: “We were able to identify at least one type of bacteria that uses these dietary compounds to boost interferon, a signalling molecule that aids the immune response.
“This prevented influenza-related lung damage in the mice. It is this kind of damage that often causes significant complications such as pneumonia in people.
“The microbes and DAT didn’t prevent the flu infection itself; the mice still had the virus.