Bacteria found in mouth and gut may help protect against severe peanut allergic reactions

One of the big mysteries in food allergy is why two people with similar levels of peanut-specific antibodies can react so differently. It turns out the answer may be in the mouth and gut's bacteria. A new study, led by researchers at McMaster University and published online in Cell Host & Microbe on March 3, 2026, shows for the first time how gut bacteria break down parts of an allergenic food and influence how a person reacts to peanuts.