Prebiotics, Probiotics, and Postbiotics

Probiotics are a hot topic in the health and wellness community, so let's take moment talk about what exactly probiotics are and what they do.

It is well established that dysbiosis can negatively influence many conditions such

as diabetes, obesity, IBD, Crohn’s disease, ulcerative colitis, and colorectal cancers.

It is also commonly accepted that pre- and probiotics can promote intestinal health

and improve the prognosis and management of such conditions. Luckily, the

microbial communities in the gut can be altered by diet, lifestyle, antibiotics, and drumroll please... probiotics.

There are three main methods that we use to directly impact the microbiome. Those are

the use of prebiotics, probiotics, and/or postbiotics. Let’s discuss the differences

between them.

Prebiotics are the main food source of our gut microbes, since the majority of our

gut microbiome lives in the colon, prebiotics must be able to hold up throughout

the entire digestive process. Most of the time we think of prebiotics as non-digestible

fibers such as inulin, which is found in various fruits and vegetables. Prebiotics keep

our microbes healthy and balanced. It helps them to grow, reproduce, and produce metabolites such as the short-chain fatty acids butyrate, propionate, and acetate, which our

human bodies can use for metabolic activities. Different prebiotics can influence

which byproducts the bacteria in the gut will produce, therefore prebiotics have

variable effects on our health.

Probiotics are living microbes that are added directly into the body. Contrary to how

things may seem, probiotic bacteria do not take up permanent or even long-term

residence in your GI system. Therefore, people generally must supplement with

probiotics for weeks or months before they see or feel any benefit. Because they

are living bacteria, probiotics represent somewhat of a risk when it comes to

immune-compromised individuals, such as patients taking immunosuppressing drugs, or patients on long-term antibiotic treatments.

For this reason, postbiotics are becoming more interesting as they do not pose the same risks because there are no live bacteria involved. Postbiotics include any substance or substances (metabolites) produced by microbes as a byproduct of their metabolic functioning. Sometimes postbiotics also contain parts of cells, enzymes or other metabolites like vitamins or minerals. Because our microbiomes are constantly metabolizing the foods we consume, postbiotics are already a part of our normal bodily systems. Often, when we talk about wanting to properly feed our gut microbes it is because we want to encourage the production of these postbiotic substances. Some of the benefits of postbiotics include their immunomodulatory, anti-inflammatory, and antioxidant effects.

What about fermented foods?

For the most part, fermented foods contain pre-, pro-, and postbiotics. Because

there are live bacteria in the food, they are consuming prebiotics in the food and

simultaneously producing postbiotics. For people who tolerate fermented foods

well, eating them regularly can be a great way to naturally support the gut

microbiome.

It is worth mentioning that while it seems intuitive to take probiotics following

antibiotic treatment, there is mixed evidence on the topic. Some research has

shown that there are benefits to taking probiotics with or following antibiotics,

while other studies have found that doing so can actually slow the recovery and

reconstitution of the natural gut microbiota.

Resources:

1. Kim SK, Guevarra RB, Kim YT, et al. Role of Probiotics in Human Gut Microbiome-

Associated Diseases. 2019;29(9):1335-1340. doi:10.4014/jmb.1906.06064

2. Żółkiewicz J, Marzec A, Ruszczyński M, Feleszko W. Postbiotics—A Step Beyond

Pre- and Probiotics. Nutrients. 2020;12(8):2189. doi:10.3390/nu12082189

3. Suez J, Zmora N, Zilberman-Schapira G, et al. Post-Antibiotic Gut Mucosal

Microbiome Reconstitution Is Impaired by Probiotics and Improved by

Autologous FMT. Cell. 2018;174(6):1406-1423.e16. doi:10.1016/j.cell.2018.08.047