Feeding Good Gut Bugs
Although all types of fiber from plant foods are an essential part of a healthy diet, some foods are especially good sources of prebiotics, special types of fiber that nourish beneficial gut bugs. These foods include apples, asparagus, Jerusalem artichokes, leeks, onions, and tiger nuts (not actually nuts, but small root vegetables).
In supplements, these are different types of prebiotics: inulin, FOS (fructooligosaccharides), GOS (galactooligosaccharides), and another form introduced more recently: XOS (xylooligosaccharides). A study at the University of California Los Angeles found that 1 gram daily of XOS reduced bad gut bacteria and enhanced beneficial bacteria in people who were healthy, overweight, or had elevated levels of blood sugar.