• Put simply, postbiotics are the by-products of the fermentation process in our guts. (iStockphoto/Getty Images)Source: iStockphoto/Getty Images
Yes, you read that right. 'Postbiotics' (not probiotics or prebiotics) is an interesting new health term to describe the waste product that's been living in our guts this whole time.
Yasmin Noone

28 Apr 2021 - 3:33 PM  UPDATED 28 Apr 2021 - 3:33 PM

Just when you thought you were up on your gut health knowledge, comes a new ‘biotics’ term to add to your vocabulary. 

A ‘postbiotic’ – not to be confused with a prebiotic or probiotic – has joined the terminology list within the ever-evolving field of gut microbiome research.

According to a 2020 review, published in the journal Nutrients, a postbiotic includes “any substance released by or produced through the metabolic activity of the microorganism, which exerts a beneficial effect on the host, directly or indirectly”. 

Put simply, postbiotics are the by-products of the fermentation process in our guts. 

“'Postbiotic’ is a fairly new term and part of an interesting new area of research related to gut health,” Accredited Practising Dietitian, Francisca Pereira-Scarfo, tells SBS.  

“Postbiotics are considered ‘waste’ products. When past studies [examined] pro and prebiotics, researchers started to note that the beneficial effects of microbiota were mediated by the secretion of these various metabolites (postbiotics).” And so, she says, a new ‘biotic’ term to describe a waste product that has always been there was born. 

Put simply, postbiotics are the by-products of the fermentation process in our guts. 

So how is a postbiotic different to the other 'biotics'? 

Although probiotics, prebiotics and postbiotics all sound similar, it’s important to acknowledge the difference between the terms and their relationship to each other. 

Pereira-Scarfo explains that probiotics are the live bacteria that are found naturally in our gut. “You can also get some probiotics from supplemental food sources like kimchi, sauerkraut, yoghurt and live cultures. 

“Prebiotics are the foods that increase the diversity of our gut bacteria. They are [found in] foods like unripe bananas, asparagus, oats, wheat bran and legumes.” 

Pereira-Scarfo, who has Malaysian and Indian heritage, cites the foods within her cultures that have gut-enhancing effects. “Almost every Indian dish we eat has onion and garlic in it, and they are high in prebiotics. We also make a lot of dhal, which features garlic, onion and lentils which have a lot of resistant starch.” 

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When the live bacteria in our gut microbiome feasts on the prebiotic fibres we consume in, for example, a serving of dahl, they produce a waste product called a postbiotic. “In other words, the live bacteria in probiotics feast on prebiotic fibres and ferment them to form postbiotics.”

Postbiotics may include short-chain fatty acids, proteins, peptides and discarded matter from microorganisms. 

Are there any benefits to postbiotics?

So what is the point of a postbiotic?

Pereira-Scarfo explains that research on the health benefits is slowly trickling in. Available evidence suggests postbiotics may have anti-inflammatory, anti-hypertensive, antioxidant, and anti-cancer properties.

It’s also proposed that postbiotics may help to boost the gut health of premature babies, young children and critically ill patients with comprised immune systems. However, more research is needed as it’s only early days. 

“Maintaining good gut health, through healthy diet and regular exercise, will give you the best chance at increasing your postbiotics and improving your overall health.”

Can I take a postbiotic supplement or eat it with food?

Postbiotic supplements and products, such as yeast fermentate marketed as a postbiotic, are starting to be made available around the world. However, Pereira-Scarfo advises against taking them because conclusive, evidence identifying the benefits of postbiotic food products or supplements for consumption is not yet available: “it’s a very grey area.” 

It’s possible that postbiotics may be found outside the body, in fermented foods – which we already know can improve the health of the gut microbiome. Pereira-Scarfo explains that’s partly because the boundary between probiotics and postbiotics has been blurred in some research trials with no clear way to distinguish whether outcomes belong to the postbiotic or probiotic effect. 

The good news is that we know we can build the diversity of our gut microbiota and improve our gut health by having a diet rich in fermented foods containing probiotics and high-fibre foods with prebiotics.

By encouraging our gut bacteria to stay alive through a healthy diet rich in resistant starch, we are also encouraging them to produce waste products – postbiotics. 

“Maintaining good gut health, through healthy diet and regular exercise will give you the best chance at increasing your postbiotics and improving your overall health.”

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