The terms prebiotics, probiotics, and recently postbiotics, are being bandied about in relation to improving gut health.   The distinction is not always clear and the term postbiotics is not widely known.  The term “biotic” is derived from the Greek word “biōtikós”, which means pertaining to life and is generally used when referring to living organisms that make up a biological ecosystem, together with their host.

Microorganisms in the gut.

We live with about 2 kg of microscopically small organisms in our gastrointestinal tracts (gut), called the gut microbiome.  Consisting of bacteria, viruses, fungi, and other single cell organisms, these microorganisms are beneficial colonizers that play an important role in four broad areas of health, namely nutrition, immunity, behavior, and disease.

Gut bacteria assist in breaking down complex molecules in food such as meat and vegetables and help with the fermentation of non-digestible substrates such as dietary fibers.  Plant cellulose would be indigestible without the aid of gut bacteria. 

The state of the gut microbiome has a significant impact on our health.  The composition of these bacterial colonies can alter the absorption as well as the metabolism of nutrients or toxins (degrade or activate) in the gut before they are absorbed into the bloodstream.

The “biotics” such as prebiotics, probiotics, and postbiotics all play different important roles to ensure a healthy and efficient gut.


Prebiotics (also referred to as fermentable fiber) are types of plant fiber that pass through the small intestines undigested and stimulate the growth and activity of certain beneficial bacteria in the large intestine.  Prebiotics are naturally present in fruit (such as bananas, apples, plums, nectarines, persimmon, grapefruit); in vegetables (such as beetroot, garlic, onions, asparagus, leeks, artichokes); in grains (such as bran, oats, couscous, whole grains); and in nuts and seeds.  Balance and variety are essential when including prebiotics in your diet.


Probiotics are certain foods or food supplements that contain live bacteria which can help restore dysbiosis in the gut and maintain digestive health.  Other benefits of probiotics include assistance with the maintenance of digestive comfort, regulation of the immune system, and balancing the gut microbiome when it has been affected by antibiotics, infections, poor diet, or external factors such as chronic stress.


While prebiotics and probiotics are known for their active components and “alive” microorganisms, the components (microorganisms) in postbiotics have been deliberately inactivated.  Hence the term “postbiotics”, which in essence refers to “after life”, meaning non-living organisms, but still with health benefits.

As recent as December 2019 an expert panel of the International Scientific Association for Probiotics and Prebiotics (ISAPP) convened to address the emerging concept of postbiotics.  They defined postbiotics as follows:

“A preparation of inanimate microorganisms and/or their components that confer a health benefit on the host.”

The word “preparation” reflects a specific formulation of microbial biomass (the mass of biological organisms).

Inanimate” means lifeless, rather than inactive, which means that live organisms have been killed, without implying loss of function.

The word “components” means that intact (“complete”) microorganisms might not necessarily be required for health effects, as health effects may also be mediated by microbial cell components, such as pili (a hair-like structure found on the surface of many bacteria), cell wall components, or other cell structures.

Various methods can be used to inactivate microorganisms.  The process starts with accurately identifying the microorganisms to be used as the starting material for the postbiotic.  Various inactivating technologies could be applied in the production of postbiotics.  Thermal inactivation processes such as pasteurization and autoclaving are widely used in the food industry, while non-thermal inactivation processes which may be used include electric field, ultrasonication, magnetic field heating, ionizing radiation, X-rays, and spray drying.

The results are inanimate microorganisms with health benefits for the host.

Postbiotics offer various benefits over probiotics, such as a longer shelf life, as well as simplified packaging and storage requirements.  For example, unlike some probiotics that must be stored at fridge temperatures, postbiotics are likely to be extremely stable for several years at room temperature.


Improving human health through microbial interactions is becoming increasingly important through interventions to modulate the gut microbiome.  The concept of postbiotics is emerging as an important microorganism-derived tool to promote human health, says the ISAPP.  In addition, as the inanimate microorganisms in postbiotics have lost the capacity to replicate, there is no risk of causing the presence of bacteria (bacteraemia) or fungi (as yeasts) (fungaemia) in the blood stream.


What are postbiotics?  A comprehensive overview.  Published 19 May 2021.  Healthline.  (

The International Scientific Association for Probiotics and Prebiotics (ISAPP) consensus statement on the definition and scope of postbiotics.  Published 4 May 2021, with Publisher’s Corrections published on 15 June 2021.  Nature Reviews.  (Journal.)  (

Postbiotics-parabiotics: the new horizons in microbial biotherapy and functional foods.  Published 20 August 2020.  Microbial Cell Factories.  BioMed Central.  (


error: Content is protected !!