The names are almost identical, which causes a lot of confusion. The difference is simple.
Probiotics are live microbes
Probiotics are living bacteria or yeasts that, in adequate amounts, provide a health benefit. They’re found in some fermented foods — yogurt and kefir with live cultures, unpasteurised sauerkraut and kimchi — and in supplements. Their effects depend on the specific strain.
Prebiotics are food for microbes
Prebiotics are types of fiber and plant compounds that your own body can’t digest but your gut bacteria can. When bacteria ferment them, they produce short-chain fatty acids that help nourish the gut lining.
Good sources include:
- Onions, garlic and leeks
- Asparagus and artichokes
- Slightly green bananas
- Oats and barley
- Beans, lentils and chickpeas
Which matters more?
For most healthy people, feeding the bacteria you already have — through plenty of varied fiber — is the most reliable way to support your gut. Probiotics can help in specific situations, such as during antibiotics or for some IBS symptoms.
A note on bloating
Prebiotic fibers are fermented, so increasing them quickly can cause gas. Add them gradually. People with IBS may find some prebiotic foods trigger symptoms.