Gut bacteria use flavonoids (found in fruits, teas, etc.) to control the immune response and protect against severe damage from the influenza virus (in mice). The specific human-associated gut microbe that protected against the influenza virus is called Clostridium orbiscindens. The bacteria metabolize flavonoids and produce a compound called desaminotyrosine (DAT) which helps produce interferon, a signaling molecule that activates the immune system. This helped protect the lungs against damage from the flu virus. The DAT did not prevent the flu but it significantly reduced the severity of it. Some of the main dietary sources of flavonoids include tea, citrus fruit, berries, red wine, apples, and legumes.