What Are Postbiotics?

September 06, 2023 7 min read

What Are Postbiotics?

In recent years, interest in pre- and probiotics has gained huge momentum. The probiotics market alone is projected to be worth a staggering $111.21 billion by 2030 as interest in our digestive health grows alongside an increased prevalence of global digestive disorders[i].

Another group of beneficial compounds that are gaining traction is postbiotics. These have been shown to benefit digestive, immune, and other areas of human health. In this article, we’ll explore what postbiotics are, how they work, and how you can incorporate them into your diet.

Prebiotics vs probiotics vs postbiotics

Before we dive into the nitty gritty of what postbiotics are, here’s a brief overview of prebiotics, probiotics, and postbiotics.

  • Prebioticsare a group of dietary compounds, mainly fibre, that are fermented or broken down by colonic bacteria, causing stimulation of their growth and/or activity and resulting in health benefits for the host[ii].
  • Probioticsare defined by the World Health Organisation as “live microorganisms which when administered in adequate amounts confer a health benefit on the host”[iii].
  • Postbioticsare beneficial compounds or the end products that are produced when good gut microbes ferment prebiotics.

What are postbiotics?

Postbiotics are bioactive compounds that are released when gut microbes, or probiotics, break down prebiotics like fibre. So, any substances that are released following fermentation that have a beneficial effect on your health can be classified as a postbiotic[iv].

Ordinarily, these compounds are a waste product of fermentation, but if they provide you with benefits, then they are a little bit more special than that. Unlike probiotics, postbiotics do not contain any live microorganisms, but they appear to exert beneficial effects in a similar way but without the risks associated with probiotics. For example, like prebiotics, postbiotics appear to cause little or no side effects but have similar effectiveness rates as beneficial live microbes.

Postbiotic examples

Because postbiotics are metabolites or microbial fragments that are beneficial for the host, they can come in all different forms.

Here are some examples of postbiotics, some of which you’ll probably already be familiar with:



Short-chain fatty acids (SCFAs)

A product of bacterial fermentation including acetate, propionate, and butyrate.


Probiotic bacteria are known to synthesise vitamins such as B12 and K when breaking down prebiotic fibres.


Polyphenols are metabolised by the gut microbiota and are known to produce postbiotics such as urolithin A.

Bacterial lysates

Mixtures that are made from bacterial components and can be used to make medicines.

Cell wall fragments

Fragments of cell walls do not contain any live organisms but may have health benefits on their own.

Cell-free supernatants

A mixture that contains biologically active compounds secreted by bacteria and yeasts into a surrounding liquid. After an incubation period, the bacteria are removed, leaving behind a liquid containing health-promoting compounds.


Exopolysaccharides (EPS) are carbohydrate polymers that are secreted by bacteria to form a closely attached layer around the bacterial cell or an extracellular slime. EPS is often used as an emulsifier, stabiliser, or water-binding agent in the food industry.


Microorganisms have developed defence mechanisms to protect them from the harmful effects of reactive oxygen species. Many have antioxidant properties that could be useful for mitigating the effects of inflammatory diseases, such as Crohn’s Disease.


You’re probably thinking, why haven’t I heard of postbiotics before? Well, you probably have, especially if you’re an avid reader of the Layer Origin blog. Because we often mention the beneficial effects of SCFAs, for example, but unlike probiotics and prebiotics, postbiotic supplements are relatively new.

Health benefits of postbiotics

The term ‘postbiotics’ may be quite new, but we’ve known about them for a while, SCFAs are a prime example. So, we know they have some cool health benefits.

And, because prebiotics, probiotics, and postbiotics are all interlinked, they can help to support one another.

Here are some of the benefits associated with postbiotic consumption.

Support healthy digestion

Of course, we couldn’t go much further without highlighting the benefits of postbiotics on the digestive system.

Numerous studies have suggested SCFAs could have anti-inflammatory effects that could slow down the development of irritable bowel disease (IBD). A study by Di Sabatino et al (2005) investigated the effect of butyrate on Crohn’s disease patients. The participants were administered 4 g/day of butyrate for 8 weeks. The results showed that 53% of patients achieved complete remission and two had a partial response, indicating that oral butyrate could be an effective treatment for IBD[v].

It's also thought that postbiotics could help to develop the proper structure of the human gut microbiota, laying the foundations for a healthy colonic environment.

Support a healthy immune system

Postbiotics have been shown to stimulate innate and adaptive immune systems, maintaining the integrity of the gut lining and eliminating pathogenic organisms through the secretion of antimicrobial compounds. These effects on the immune system are like those elicited by probiotics, except postbiotics do not require ‘live’ organisms to facilitate their effects[vi].

There have been several proposed mechanisms of postbiotics in the modulation of the immune system. Some probiotic bacteria produce compounds that have immunomodulatory effects. For example, Lactobacilliproduce pili and protein p40/p75 that help protect the gut barrier from opportunistic pathogens.

Other studies have shown that exopolysaccharides (EPS) produced by some bacteria can have a positive effect on the immune system. Streptococcus thermophilusCRL1190 and its EPS have been shown to reduce the adhesion of Helicobacter pyloriand reduce the immune response in gastric epithelial cell lines. Therefore, protecting against H. pyloriinfection[vii].

But that’s not all, there are other mechanisms too. Like the SCFA butyrate that can control the body’s overall immune response by stimulating the production of T cells. Or the production of cytokines, anti-inflammatory messengers by cell wall fragments and cell-free supernatants, to lower inflammation or stimulate an immune response.

Lower blood sugar levels

Postbiotics may help to reduce the risk of obesity and lower blood sugar levels. The postbiotic, muramyl dipeptide, can promote insulin signalling during a state of metabolic endotoxemia[viii].

In mouse studies, another postbiotic, urolithin A, has been shown to reduce blood glucose levels and increase glucose tolerance and insulin sensitivity[ix]. Further studies have also highlighted how butyrate can reduce blood glucose levels which in turn can help to control body weight and insulin sensitivity[x].

Therefore, postbiotics could have therapeutic potential for treating diabetes and high blood sugar levels.

Postbiotics as a treatment for diarrhoea

Research shows that postbiotics could be effective for the treatment of diarrhoea.

In a systematic review published in 2020, seven randomised control trials involving 1740 children found that the administration of heat-killed Lactobacillus acidophilusLB reduced diarrhoea duration. While another heat-inactivated probiotic used in two RCTs lowered the risk of diarrhoea in children[xi].

In another study, 137 adults with chronic diarrhoea were randomly assigned to either a postbiotic or probiotic group. By the end of the study, the group who had been given a postbiotic (L. acidophilusLB) reported improved symptoms, suggesting that a postbiotic may be more effective at treating chronic diarrhoea than a living probiotic[xii]

Further health benefits

These are not the only health benefits associated with postbiotics. Further research has shown they may:

  • aid weight loss
  • have antiatherosclerosis properties, helping reduce the risk of coronary heart disease
  • help reduce the severity of certain allergies
  • have anti-tumour benefits
  • cause less side effects compared to probiotics


How to ensure you’re getting postbiotics in your diet

Unlike prebiotics and probiotics, postbiotic supplements aren’t as easy to obtain. However, you may have seen them in health food shops and online. Rather than being specifically labelled postbiotics, you may have seen examples like sodium butyrate or urolithin A.

One of the best ways to boost your postbiotic intake is to increase your consumption of pre- and probiotics, as these will help to naturally increase the production of postbiotics by your gut microbiota.

Try foods like:




Live yoghurt







Chicory root









Don’t forget human milk oligosaccharides (HMOs) too. HMOs are a great natural prebiotic source that helps to nourish your gut microbiota and encourage it to flourish. At Layer Origin Nutrition, we have a wide range of HMO products to meet your needs.


Postbiotics are health-promoting compounds that are naturally produced by the good bacteria residing in your gut. Because they are a product of fermentation, they may generally be thought of as a waste component, but like probiotics and prebiotics, they offer numerous health benefits.

Although you may not specifically find ‘postbiotic’ labelled products in shops or online, you can help to boost their production by including prebiotic and probiotic foods into your diet. By doing so, you’ll be proactively supporting many different aspects of your health including digestive, immune, and metabolic.


Written byLeanne Edermaniger, M.Sc. Leanne is a professional science writer who specializes in human health and enjoys writing about all things related to the gut microbiome. 



[i] Grand View Research I. Probiotics market size worth $111.21 billion by 2030: Cagr: 7.5%: Grand View Research, inc.. [Internet]. 2022 [cited 2023 Aug 28]. Available from: https://www.prnewswire.com/news-releases/probiotics-market-size-worth-111-21-billion-by-2030--cagr-7-5-grand-view-research-inc-301479436.html

[ii] Davani-Davari D, Negahdaripour M, Karimzadeh I, Seifan M, Mohkam M, Masoumi SJ, Berenjian A, Ghasemi Y. Prebiotics: Definition, Types, Sources, Mechanisms, and Clinical Applications. Foods. 2019 Mar 9;8(3):92. doi: 10.3390/foods8030092. PMID: 30857316; PMCID: PMC6463098.

[iii] Hill C, Guarner F, Reid G, Gibson GR, Merenstein DJ, Pot B, et al. The International Scientific Association for Probiotics and prebiotics consensus statement on the scope and appropriate use of the term probiotic. Nature Reviews Gastroenterology & Hepatology. 2014;11(8):506–14. doi:10.1038/nrgastro.2014.66

[iv] Żółkiewicz J, Marzec A, Ruszczyński M, Feleszko W. Postbiotics-A Step Beyond Pre- and Probiotics. Nutrients. 2020 Jul 23;12(8):2189. doi: 10.3390/nu12082189. PMID: 32717965; PMCID: PMC7468815. 

[v] Di Sabatino A, Morera R, Ciccocioppo R, Cazzola P, Gotti S, Tinozzi FP, Tinozzi S, Corazza GR. Oral butyrate for mildly to moderately active Crohn's disease. Aliment Pharmacol Ther. 2005 Nov 1;22(9):789-94. doi: 10.1111/j.1365-2036.2005.02639.x. PMID: 16225487.

[vi] Yeşilyurt N, Yılmaz B, Ağagündüz D, Capasso R. Involvement of probiotics and Postbiotics in the immune system modulation. Biologics. 2021;1(2):89–110. doi:10.3390/biologics1020006

[vii][vii] Marcial G, Villena J, Faller G, Hensel A, de Valdéz GF. Exopolysaccharide-producing streptococcus thermophilus CRL1190 reduces the inflammatory response caused by helicobacter pylori. Beneficial Microbes. 2017;8(3):451–61. doi:10.3920/bm2016.0186

[viii] Bourebaba Y, Marycz K, Mularczyk M, Bourebaba L. Postbiotics as potential new therapeutic agents for metabolic disorders management. Biomedicine & Pharmacotherapy. 2022;153:113138. doi:10.1016/j.biopha.2022.113138 

[ix] Raimundo AF, Ferreira S, Tomás-Barberán FA, Santos CN, Menezes R. Urolithins: Diet-Derived Bioavailable Metabolites to Tackle Diabetes. Nutrients. 2021 Nov 27;13(12):4285. doi: 10.3390/nu13124285. PMID: 34959837; PMCID: PMC8705976.

[x] Mayorga-Ramos A, Barba-Ostria C, Simancas-Racines D, Guamán LP. Protective role of butyrate in obesity and diabetes: New insights. Front Nutr. 2022 Nov 24;9:1067647. doi: 10.3389/fnut.2022.1067647. PMID: 36505262; PMCID: PMC9730524.

[xi] Malagón-Rojas JN, Mantziari A, Salminen S, Szajewska H. Postbiotics for Preventing and Treating Common Infectious Diseases in Children: A Systematic Review. Nutrients. 2020 Jan 31;12(2):389. doi: 10.3390/nu12020389. PMID: 32024037; PMCID: PMC7071176.

[xii] Xiao SD, Zhang DZ, Lu H, Jiang SH, Liu HY, Wang GS, Xu GM, Zhang ZB, Lin GJ, Wang GL. Multicenter, randomized, controlled trial of heat-killed Lactobacillus acidophilus LB in patients with chronic diarrhea. Adv Ther. 2003 Sep-Oct;20(5):253-60. doi: 10.1007/BF02849854. PMID: 14964345.

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