Probiotics, prebiotics — now postbiotics? What's known and not about latest gut research

Probiotics have been all the rage the last few years, as more food companies advertised the active bacteria in their products and consumers became more aware of the role of bacteria in keeping their gut healthy. 

Also in the "biotics" family is prebiotics, the stuff that probiotics eat, such as high-fibre foods.

Postbiotics is a less familiar term, but one some microbiologists say is a huge area of interest.

"Understanding what the microbiota is and how it changes in disease, that was a huge deal five years ago," said Lisa Osborne, an assistant professor in University of British Columbia's microbiology and immunology department. 

"Then we realized maybe it's not necessarily who's there but what they're doing, the postbiotics that are being produced and how that's influencing the host's post-response. It's still a relatively new field."

Postbiotics are the waste left behind after your body digests probiotics and prebiotics. Some postbiotics are the product of fermentation and some postbiotics are the structural parts of the cells themselves. 

They can be found in fermented foods, but your gut can also make them, Jennifer Stearns, a microbiologist and assistant professor in McMaster University's department of medicine, told Dr. Brian Goldman, host of CBC's The Dose. 

Although an official definition of postbiotics has been decided by experts only within the last year, researchers have been well aware of postbiotics in the human gut for several years.  

"People are trying to figure out how to improve their gut health in order to improve their overall health. And postbiotics are just part of that conversation," Stearns.

Yet, even if the term is already popping up on commercial supplements, there are still many unknowns when it comes to postbiotics and any potential health benefits, Stearns said. 

Last year,  a group of experts from around the world specializing in nutrition, microbiology, food science and other research areas came to a consensus on the definition of postbiotics. 

The panel organized by The International Scientific Association of Probiotics and Prebiotics (ISAPP) agreed a postbiotic is a "preparation of inanimate microorganisms and/or their components that confers a health benefit on the host."

Most people will get postbiotics from fermented foods like kefir or kimchi. 

"When you eat fermented foods, then you're getting all of it. You're getting the prebiotic, the probiotic and the postbiotic. It's the super mix," Stearns added.