Postbiotics - What happens beyond pre and probiotics?

A deep dive into what postbiotics.  What they are and why they matter for our health.

As you may have noticed, we’re strong advocates of both prebiotics and probiotics and how they can benefit our health, but what’s the story with postbiotics?  Before we take a deep dive into the role of postbiotics, let’s give a quick insight into what prebiotics and probiotics actually are!

Prebiotics and Probiotics – A recap before we dive in...

Prebiotics are specific types of fibre that act like fuel for our friendly gut bacteria.  The predominant types that have a beneficial effect on human health include: inulin, fruto-oligosaccharides and galacto-oligosaccharides. These chains of fibre are not easily digested by humans but readily fermented by our beneficial gut flora. Rich dietary sources of these type of fibres include Jerusalem artichoke, chicory, lentils, onions, garlic and leeks. 

Fibre is an often-overlooked element of diet yet perhaps one of the most important that we should all be thinking about. If we fuel our microbiome well with a rainbow of foods with varying types of fibre, it serves to fuel us well.  It is through feeding our friendly gut flora with these specific types of fibre, that they are then broken down into these compounds called postbiotics.   These compounds keep our digestive system healthy and also have beneficial activity in various organs in our body through absorption and transportation in our circulation[i].

The word probiotic itself comes from the Latin ‘pro’ meaning ‘for’ and the Greek word ‘biotic’ meaning ‘life’.  The term itself was first coined in the journal of Science in 1965 but the definition currently more widely used is that probiotics are ‘live microorganisms that, when administered in adequate amounts, confer a health benefit to the host’[ii].  Probiotics, as found in all YourGut supplements, include various types of lactic acid bacteria such as Lactobacillus and Bifidobacteria, alongside other types of bacteria and yeasts such as Saccharomyces boulardii. 

We have long been consuming fermented foods by way of preserving foods but also for their health benefits too.  It is only more recently that we have been able to isolate specific bacterial strains and understand their unique benefits to our health. By consuming probiotics in both foods or supplement format, they have the ability to favourably adjust our digestive environment, to inhibit any pathogenic microbes, to improve the balance of the intestinal flora, to regulate our immune systems and to maintain healthy digestive tissue protecting against conditions such as intestinal permeability (known as leaky gut)[iii].

Postbiotics – A deep dive into the world within in.

We know that we hold a symbiotic relationship with our gut microbiome and that a healthy microbiome its directly correlated to human health. But why?  This is where postbiotics come in. By definition, postbiotics are any substance released by or produced through the metabolic activity of microorganisms, which exert a beneficial effect on the host, directly or indirectly[iv]. It is with a healthy microbiome and fermentation of the foods including dietary fibre and resistant starch, that postbiotics are produced.  Think of it as pre + pro = post.  Postbiotics can take many forms so let’s take a deeper look into some of the various types and their functions.

Short Chain Fatty Acids

We see the balance of short chain fatty acids (SFCAs) on functional microbiome tests and these include acetate, propionate and butyrate.  They are a subset of fatty acids found predominantly in the proximal colon where they are used both locally and transported across the epithelium into the bloodstream. 

Functions of SCFAs are extensive as they play a major role in maintenance of gut integrity and immune homeostasis[v]. Each different SCFA also has different roles.  Butyrate, for example, acts a major energy source for the colon cells keeping the gut lining in good health and having strong anti-inflammatory activity. Acetate, and its related metabolism of acetyl-CoA, is much more involved in energy production and regulation of metabolism and is one of the most abundant SCFAs[vi].  Propionate also plays a role in energy metabolism but also has an interesting role when it comes to brain health with neuroprotective and regenerative effects[vii].

Enzymes

We think of organs such as the pancreas when it comes to digestion and assimilation of nutrients but our microbiome also has the ability to manufacture enzymes including amylase, lipase, protease, lactase and peptidases through postbiotic activity.  More interestingly, studies are showing improved levels of antioxidant enzymes when supplementing with specific probiotic strains such as Lactobacillus plantarum and Lactobacillus rhamnosus.  These studies show improved levels of protective enzymes such as superoxide dismutase, catalase and glutathione peroxidase following supplementation, together with reductions in reactive oxygen species and inflammatory markers including c-reactive protein[viii]. 

Peptides

Antimicrobial Peptides (AMP) include bacteriocins produced by lactic acid bacteria. These have high specificity against microbial pathogens yet with low cytotoxicity to human cells, thereby playing an important role in immunity[ix].

Vitamins

A well documented postbiotic effect is the manufacture of specific vitamins including vitamin B12, B2, B6, folate and vitamin K[x]. A reason we should focus on digestive health first when considering status and optimisation of these vital nutrients.  In one study, probiotic supplementation activity increased blood levels of vitamins B6 and B12 in pregnant women[xi].

Exopolysaccharides

Exopolysaccharides modulate the immune response by interaction with dendritic cells and macrophages whilst enhancing the activity of T and NK lymphocytes.  There are various classes with multiple beneficial effects, one of which is beta-glucans which can interact with dectin-1 receptors to activate them thereby supporting the immune system[xii].  Beta-glucans may also have a positive effect on the efficacy of probiotics by facilitating the adhesion of lactobacilli to the intestinal epithelium[xiii].

Cell wall fragments

These are the cell wall of specific bacteria and include teichoic and lipoteichoic acids. These play a crucial role in host immunity and have been shown to have both immunomodulatory and antioxidant properties[xiv].

Cell Free Supernatants

These are the metabolites secreted by bacteria and yeast and supernatants from different strains seem to have differing activities.  Whilst Lactobacillus acidophilus and Lactobacillus casei supernatants have anti-inflammatory and antioxidant effects, Lactobacillus plantarum has been shown to have positive effects on the maturation and structure of the intestinal barrier. Supernatants from Saccharomyces boulardii have been shown to reverse the state of disturbed peristalsis in response to stress[xv].

Other postbiotics exist such as bacterial lysates and some amino acids can be considered postbiotics too. 

Harnessing postbiotics

As you can see, postbiotic activity is critical but we need all of the right precursors are in place to optimise postbiotic activity.  It is therefore important not to go straight to the end target but ensure that all of the foundation ‘pre’ and ‘pro’ elements are supported first.  With the right types of fibre in our diet together with a healthy microbiome, we will get the best natural postbiotic activity to support our health. To support the health of the microbiome, we should encourage elements such as consumption of healthy prebiotic rich fibre and fermented foods.  We should also support measures to address the factors that disrupt the balance of the microbiome such as processed foods and stress.  Prebiotic and probiotic (symbiotic) supplements may also be supportive too.  It seems that synergy here matters with studies showing greater efficacy with multi-strain forms[xvi] such as the bespoke blends carefully selected for each of the YourGut products.

Go forth… feed, seed and flourish.

By Jacklyn Coldwell BA (Hons) Dip CNM, mBANT, mIFM

Co-founder of YourGut