Probiotics are live microorganisms that may provide a benefit when consumed in adequate amounts. Effects are strain-specific, so evidence for one product does not automatically apply to another.
What to keep in mind
Prebiotics are substrates used by beneficial microbes. They include certain fermentable fibers found in foods such as onions, garlic, legumes, oats, and slightly green bananas.
Supplements are not necessary for everyone and may worsen symptoms in some people. A varied plant-rich diet is a practical foundation, while specific conditions deserve individualized advice.