What are postbiotics?

Ask the doctors

Q. I know about prebiotics and probiotics, but I recently heard the term postbiotics. Can you explain what they are?

A. As you may already know, probiotics are living microorganisms found in certain foods, such as yogurt, sauerkraut, and some cheeses, which are crucial to good digestion. When you eat these foods, it helps your digestive tract and overall wellness by promoting a healthy balance of beneficial bacteria and other microorganisms in your gut microbiome, a collection of 100 trillion tiny critters living in your intestines.

Prebiotics act as food for the probiotics. Foods with healthy amounts of fiber, such as beans, whole grains, and certain vegetables, break down in your body to create substances that help probiotics to grow and thrive within your gut.

So, what are postbiotics? This term refers to the waste left behind after your body digests both prebiotics and probiotics. Healthy postbiotics include nutrients such as vitamins B and K, amino acids, and substances called antimicrobial peptides that help to slow down the growth of harmful bacteria. Other postbiotic substances called short-chain fatty acids help healthy bacteria flourish.

You can increase the amount of useful postbiotics in your system by increasing your intake of fermented foods, such as kefir, tempeh, and kimchi. Focusing on getting enough of the foods that promote a mix of healthy gut bacteria may help improve your overall health.

— Toni Golen, M.D., and Hope Ricciotti, M.D.
Editors in Chief, Harvard Women's Health Watch

Image: Mikhail Dmitriev/Getty Images