Natural compounds found in berries, tea and red wine are known to have protective properties that help regulate the immune system to fight infections.
Now, a new study shows that the flavonoids in these products works with a particular gut microbe to prevent severe flu infections.
In their tests on mice, scientists explained that this did not stop the highly contagious infection being contracted. But the mechanism boosted the immune system and prevented the flu from harming the lung tissue.
The researchers said the findings could help explain why people have varied reactions to the infection. Most people will feel better from influenza within a week but it can be dangerous for the elderly or people with certain illnesses.
Around the world, the World Health Organization estimates it causes 250,000 to 500,000 deaths annually.
Previous evidence suggests that the gut microbiome may be important in protecting against severe influenza infections.
The new research, carried out at Washington University School of Medicine in St Louis, aimed to identify the exact gut microbes that might provide that protection. Additionally, nutritionists have long explored the potential health benefits of flavonoids. They discovered that the microbe clostridium orbiscindens was protective.
They believe it interacts with the dietary compounds to boost interferon, which are proteins produced by the body's cells as a defensive response to viruses.
The metabolite that triggered the reaction is called desaminotyrosine, otherwise known as DAT.
