The intricate relationship between gut microbiota and overall human health has become a focal point of modern health research. From a robust immune system to better mental health, the health of our gut plays a crucial role in our well-being. As people gain a deeper understanding of gut health, microbial modulation, particularly the development of beneficial bacteria, remains a key area of interest. One of the most mature and effective measures is the use of probiotics. However, other related terms—prebiotics and postbiotics—are less well-known. So, what are these substances, and how do they contribute to our health?

What are Probiotics, Prebiotics, and Postbiotics?

Prebiotics: The Fuel The International Scientific Association of Probiotics and Prebiotics (ISAPP) defines prebiotics as “a substrate that is selectively utilized by host microorganisms conferring a health benefit.” [1] Simply put, prebiotics serve as food for our innate gut microbiota as well as the exogenous eaten probiotics, providing the necessary nutrients for their growth and proliferation [2]. Additionally, prebiotics promote bowel movements and prevent constipation [3]. Through a fermentation process, they can produce short-chain fatty acids (SCFAs) in the gut that help promoting the growth of good gut bacteria [2].

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Probiotics: The Factory The ISAPP defines probiotics as “live microorganisms that, when administered in adequate amounts, confer a health benefit on the host.” [4] They protect the gut by competitively excluding pathogenic bacteria, regulating and stabilizing the gut microbiota, enhancing the gut epithelial barrier function, and modulating the gut mucosal immunity [2]. However, there are many types of probiotic strains that come from different families of bacteria and yeasts. Therefore, the health benefits of probiotics are strain specific, individual specific, and require the intake of a certain number of live bacteria [2].

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Postbiotics: The Metabolic Byproducts of Probiotics The ISAPP defines postbiotics as “a preparation of inanimate microorganisms and/or their components that confers a health benefit on the host.” [5] This means that live microorganisms have been intentionally inactivated, leaving behind the components that confer health benefits on the host. These components include inactivated microbial cells, cell wall components, SCFAs, bacteriocins, exopolysaccharides, and other bioactive metabolites [2]. Due to their small size, they can quickly penetrate the gut mucosa and confer various health benefits, including modulation of the gut microbiota composition by inhibiting the invasion and growth of pathogens, enhancing gut barrier function by excreting antimicrobial activity and modulating immune response [2]. In addition, postbiotics are by nature nonviable and do not replicate in the gut, so they have been studied as a safer alternative to probiotics, especially for immunocompromised individuals.

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The Bottom Line

Understanding the roles of prebiotics, probiotics, and postbiotics reveals their roles in maintaining and enhancing our gut health. Each of these elements contributes uniquely to maintaining and enhancing our well-being. Prebiotics act as the fuel, nurturing the growth and activity of beneficial gut bacteria, while probiotics introduce the bacteria themselves directly. Postbiotics, on the other hand, provide additional benefits through their metabolic byproducts, offering a complementary approach that enhances the gut environment without requiring live microorganisms.

References

1. Gibson, Glenn R et al. “Expert consensus document: The International Scientific Association for Probiotics and Prebiotics (ISAPP) consensus statement on the definition and scope of prebiotics.” Nature reviews. Gastroenterology & hepatology 14,8 (2017).
2. Ji, Jing et al. “Probiotics, prebiotics, and postbiotics in health and disease.” MedComm 4,6 e420.
3. Naseer, Maliha et al. “Therapeutic Effects of Prebiotics on Constipation: A Schematic Review.” Current clinical pharmacology 15,3 (2020): 207-215.
4. Hill, Colin et al. “Expert consensus document. The International Scientific Association for Probiotics and Prebiotics consensus statement on the scope and appropriate use of the term probiotic.” Nature reviews. Gastroenterology & hepatology 11,8 (2014): 506-14.
5. Vinderola, Gabriel et al. “Frequently asked questions about the ISAPP postbiotic definition.” Frontiers in microbiology 14 1324565.