Probiotics, prebiotics, and postbiotics: What, where, why?
Food Alchemist Reflections #2. Ferment-nation
In a world that has been built by words and words that have been created by humans, where does nature take the lead? It is time for a change, re-think what has been already established by our words, and create a new paradigm that includes us as part of nature. How? Through Food. Food is our common treasure, the best indicator of our planet’s health. These words represent an out-loud thought from The Food Alchemist Lab that endeavors to take you on a trip around general and specific food topics → proposing solutions, destroying myths, and waking up your interest through impactful recipes. Because your curiosity is our trigger and, once you’ve shot us, nothing will stop us from bringing a better food system, the one that listens to nature’s voice.
1. First things first
The current overfeed world
Advances in modern medicine have reduced the risk of death from communicable diseases such as measles, pneumonia, diarrhea, tuberculosis, etc. However, current overnutrition in developed and developing countries is linked to the cause of death from chronic non-communicable diseases (CNCDs) such as Diabetes Mellitus, Cancer, cardiovascular diseases, etc.
This overnutrition situation has drastically changed our food lifestyle where natural foods have been displaced by ultra-processed foods. This dietary shift is related to the increase of certain harmful groups of microorganisms in our intestine, linked to the aforementioned diseases. But now, people are more aware of gut health, that’s why the “-biotics” market is growing exponentially.
The “-biotics” market
Over the past ten years, the words microbiome, probiotics, gut health, prebiotics, and postbiotics have been trending, according to Google Trends. This trend is evident in the explosive growth of the probiotics market, estimated at USD 49.4 billion in 2018, it is projected to increase to USD 69.3 billion by 2023, with 82% comprising functional foods and beverages. Consumers are now also looking for prebiotics to improve their gut microbiome either through enriched or natural foods. In 2019, this market reached USD 250 million, with most of these products used as nutritional enhancers and as sweeteners.
Recently, an emerging market for postbiotics is also growing. This trend is also reflected in scientific literature. In 2013, there were just four articles published, while in 2020, that number jumped to 95. Some of these articles are focused on postbiotic stability in foods while others focus on their description because postbiotics are not well defined yet. Postbiotics in foods is an incoming landscape.
The “-biotics” market is growing, and people (including you), are mentioning these words more and more. However, all of us could be asking some questions: What are they? Where are they present? Why is gut health so important?
2. What, where, and why -biotics?
What?
- Probiotics: The World Health Organization (WHO) defines probiotics as “live microorganisms which, when administered in adequate amounts, confer a health benefit on the host.” Here, you can find the probiotic strains accepted by the European Food Safety Authority (EFSA).
- Prebiotics: The International Scientific Association of Probiotics and Prebiotics (ISAPP) define them as a non-digestible substrate (typically carbohydrates) that is selectively utilized by host microorganisms conferring a health benefit. They can be extracted from plants, transformed by enzymatic hydrolysis, synthesized from mono- or disaccharides such as sucrose or lactose. Table 1 below presents the accepted and candidate prebiotics.
- Synbiotics: These are defined as synergistic mixtures of probiotics and prebiotics that beneficially affect the host by improving the survival and colonization of live beneficial microorganisms in the gastrointestinal tract.
- Postbiotics: There is not yet a common definition, but they could be defined as the functional fermentation compounds produced by probiotics that have a health effect on the host. The most known postbiotics are short-chain fatty acids (SCFAs), components like microbial fractions, functional proteins, secreted polysaccharides, and extracellular polysaccharides (EPS).
Table 1. List of accepted and candidate prebiotics. Source: Lockyer, S. et Stanner, S. (2019).
Where?
All of these products are typically presented in one of two formats: dietary supplements or within foods. Even so, consumers usually prefer the second option. For this reason, this article will analyze where they are presented and how they are generated in foods.
Probiotics are microorganisms, which means that they have to be added or grown by themselves in foods. The probiotics admitted by the EFSA are specific strains that are linked to functional benefits. Thus, they should be added in specific amounts to ensure a sufficient final quantity in the probiotic-claimed product. Moreover, depending on the food matrix, some probiotics could have better growth than others, for example, Lactobacillus plantarum C2 showed different enzymatic pathways depending on the fruit juices where it was inoculated, increasing or decreasing its bioactivity (Szutowska, J, 2020). However, microorganisms that are not officially probiotics, but that also grow in foods (Lacto-fermented vegetables, cheese, or sourdough) are also beneficial to our gut health. Eating fermented foods will be better whether or not probiotics.
Otherwise, prebiotics are naturally present in fruits, whole grains, legumes, and vegetables. Also, they could be added as ingredients to products, but they have different uses in the function of the product pH, temperature, and pressure stability. Table 2 shows some examples of applications and their technological properties.
Table 2. Food applications of prebiotics. Source: Yanbo Wang (2009)
Finally, postbiotics can be present in foods by addition or derived from probiotic growth, and currently, they are being researched for their stability. Postbiotics seem to be more functional stable than probiotics because they are not an alive system influenced by multiple factors. Thus, the actual challenge is translating scientific knowledge into commercial applications to have earlier postbiotic foods (Yanbo Wang, 2009).
Why?
The use of “-biotics” foods by our grandparents, such as kefir, specific fruits, wild herbs, or kombucha, is a traditional healing habit in the world. Who has not heard about eating plums or kiwis when constipated? Who has not heard someone say that they were feeling better after one week using kombucha or kéfir? All of these are because of “-biotics.”
We know that our overall health depends on both our mental as well as our gut health. But if our total bacteria mass is heavier than our brains, what is more essential: the egg or the chicken? The statement “the gut is our second brain” is becoming more and more popular because of the connection between our microbiome and our brains. The gut-brain axis, comprising different connections mediated by neurotransmitters, and postbiotics, such as gamma-aminobutyric acid (GABA) or short-chain fatty acids (SCFA), act as such in the gut-brain axis (Davidson et al., 2018).
So, eating could modify our behavior, but why? Our intestines are constituted by three phyla (Bacteroidetes, Actinobacteria, and Firmicutes), where Bacteroidetes and Firmicutes represent 90% of the total microbiota. And our gut health could be interpreted simply thanks to the Firmicutes/Bacteroidetes ratio (a lower ratio is related to better gut health and a higher to worse). There is not 100% consensus within the scientific community. Some studies declare that the ratio is not health reliable (Magne et al., 2020; Rinninella et al., 2020). So, what should we eat to increase these benefits and reduce those harmful bacterias? Let’s learn by facts.
As you know, the western diet is high in red meat, ultra-processed foods, processed red meat, refined sugar, and low in fruits, vegetables, cereals, and legumes, while a plant-grain-based diet is almost the opposite. Different gut biomarkers of Europeans and Africans with a western and plant-grain-based diet, respectively, were compared before and after changing their dietary patterns. Results showed that in almost 40 days, European guts improved, and African guts dramatically worsened. We also should add that the African diet is rich in fermented foods (non-alcoholic or low alcoholic beverages, sour porridge, fermented cassava, sour milk, etc.). It means more prebiotics and alive microorganisms.
Our lifestyle influences our gut and our gut influences our general wellbeing. We can modify it, including more vegetables, fruits, whole cereals (full of prebiotics), and fermented foods (full of potentially probiotics and post-biotics). That’s why we want your second brain happier, thanks to the following amazing recipe, which summarizes the purpose of this article.
3. In-a-nutshell recipe
In a fast world where ready-to-eat, ultra-processed, and fast food is on our shelves, we need slow, healthy, and tasty alternatives. As we explain the holistic meaning of these new words, you may be asking yourself how you can apply this knowledge in your daily routine, in the simplest way. Because of that, we have included this recipe that gathers all this theoretical content in an application. Thus, you will be able to include it into your lifestyle in a long-term prospect.
4. References
Davidson Gabrielle L., Cooke Amy C., Johnson Crystal N. and Quinn John L. (2018). The gut microbiome as a driver of individual variation in cognition and functional behaviour. Phil. Trans. R. Soc. B, 373 (1756). http://doi.org/10.1098/rstb.2017.0286
Lockyer, S. and Stanner, S. (2019). Prebiotics — an added benefit of some fibre types. Nutr Bull, 44, 74–91. https://doi.org/10.1111/nbu.12366
Magne, Fabien; Gotteland, Martin; Gauthier, Lea; Zazueta, Alejandra; Pesoa, Susana; Navarrete, Paola; Balamurugan, Ramadass (2020). “The Firmicutes/Bacteroidetes Ratio: A Relevant Marker of Gut Dysbiosis in Obese Patients?” Nutrients 12 (5). 1474. https://doi.org/10.3390/nu12051474
Rinninella, E., Raoul, P., Cintoni, M., Franceschi, F., Miggiano, G., Gasbarrini, A., & Mele, M. C. (2019). What is the Healthy Gut Microbiota Composition? A Changing Ecosystem across Age, Environment, Diet, and Diseases. Microorganisms, 7 (1), 14. https://doi.org/10.3390/microorganisms7010014
Szutowska, J (2020). Functional properties of lactic acid bacteria in fermented fruit and vegetable juices: a systematic literature review. Eur Food Res Technol 246, 357–372 . https://doi.org/10.1007/s00217-019-03425-7
Yanbo Wang (2009). Prebiotics: Present and future in food science and technology. Food Research International, 42 (1), 8–12. https://doi.org/10.1016/j.foodres.2008.09.001.
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