One of my major goals as a dietitian is to increase the state of appreciation for writing as a tool to not only convey nutrition information but to enhance the state of understanding we as health professionals are able to achieve.

To that end I’m thrilled to be introducing my new writing intern Leeauna Duchesne who has today prepared for us an article exploring the difference between probiotics and fermented foods.

I know this topic is one of great interest to both the general public and my colleagues alike, so I truly hope you enjoy it.

Probiotics Vs Fermented Foods

 By Leeauna Duchesne with review and editing by yours truly

Probiotics foods are special and atypical in that they contain a tested and specific type of live bacteria that have been proven to be linked to certain health benefits.

Common probiotic foods that you may be familiar with are: probiotic yogurts (think Activia), kefir, nutrition bars, cereals, supplement powders, and beverages like kombucha (Jager et al., 2019).

While probiotic foods are typically nutrient packed, tasty and trendy, they are, however, straight up misunderstood!

Considering how often probiotic foods are confused with fermented foods (just ask Google), and also how unsure I was myself about the differences of these foods- I decided to go straight to the science and the research to find answers (and many many weeks of reading material!).

Like you, I am always looking to improve my understanding around food, as there is too much information out there, and I wanted to determine and better explain the differences of probiotic and fermented foods and why these are often ‘mislabeled’ or confused as the same. So, let’s take a look at some of the stark differences.

Probiotic foods require a known stain of beneficial bacteria that has been thoroughly tested for its quality, numeration and DNA make-up before use (Reid et al., 2008).

Labelling and words to look for on verified probiotic products include: ‘live and active cultures’, contains ‘x’ amount of probiotics, etc. and these labels are often used on probiotic  products like juices, cereals, and dairy products (Reid et al., 2008).

Sometimes, these foods will also list the name of the strain of bacteria used.

As for other probiotic foods or beverages like kombucha, you can also find the estimated amount of live microbes (*usually guaranteed at the time of processing/bottling or by the expiration date) displayed on the label/packaging, and this quantity is typically estimated and expressed in colony forming units (CFU’s) or in millions of billions (Reid et al., 2008).

Fermented foods, on the other hand, are less specific in their labelling, but have a lot of emerging evidence in science based research as being potentially just as beneficial to health, in comparison to probiotic foods. However, to date fermented foods are significantly understudied and more research funding is necessary (Marco et al., 2021).

There are many more types of fermented foods available than probiotic foods and examples include: non-probiotic/fermented yogurt, cheese, tempeh, tofu, sour cream, cottage cheese, grains, miso, and fermented vegetables like Kim Chi (Marco et al., 2021).

You can think of fermented foods as a mixed bag or consortia of bacterial and active cultures (Marco et al., 2021). More than this, fermented foods can also be probiotic foods (fermented-probiotic foods) but require well-studied and common bacteria present in the make-up of the food product (Marco et al., 2021).

With that being said, because the testing and labeling is so stringent for verified probiotic foods, most fermented foods wouldn’t actually qualify if fully tested, as there would likely be inconsistencies in the types of live bacteria and their quantities (Marco et al., 2021).

A good example of this would be a popular fermented food KimChi: (Made from napa cabbage) and often labeled as probiotic, but is technically only verified-fermented since there is usually no probiotic strain listed, no quantity of probiotics guaranteed and no time frame for microbe survival.

Does Pasteurization Kill Probiotics?

High temperature thermal processing, such as the standard pasteurization process, is commonly used in quality control of most probiotic and fermented food products, and this standard safety practice does sadly kill a certain amount of the live bacteria in both these types of foods.

It is actually common for probiotic and fermented food products to contain these heat-killed cells that used to be live microbes. These tiny bacteria are hopefully still alive by the time you ingest them, however, if the probiotics in your yogurt container or glass of kombucha are no longer alive during consumption (or die while being digested), there is some good news. Across many studies the evidence suggests that these post-mortem cells also have the caliber to improve aspects of physiology and health and can be used beyond their best before date  (Nataraj et al., 2020 ; Siciliano et al., 2021).

In fact, there has been a recent uptick in  research related to immunobiotics, what these  no longer live probiotics are being called,  and a few of the observed health benefits include: allergy reduction and management (for ex. was used as a treatment for atopic dermatitis etc.), and significant in improving the reaction and or symptoms related to lactose intolerance and malabsorption (De Vrese & Schrezenmeir, 2008; Jager et al. 2019).

Final Thoughts

The most effective and efficient way to ensure you are consuming the best quality probiotic foods is to remember the labeling requirements (strain of bacteria, quantity, and how long this is guaranteed for), as these details represent the gold standard of testing. These specifics will also help you determine whether a fermented food is actually probiotic or not.

Dairy-based foods do seem to represent the most common probiotic foods available, but there are many other options now for anyone with an allergy or symptoms related to the malabsorption of lactose.These plant based foods also contain beneficial probiotics, bacterial cultures and bioactive peptides etc. (Marco et al., 2021).

For fermentation to occur, three things are required: time for fermentation, a bacteria/ microbial strain, and a protein source  (Chakrabarti et al., 2018).

Keep these three things in mind while looking for fermented foods.

All in all, verified probiotic foods are first rate and fermented foods need some more attention and avocation but are also valuable to health.

Currently,  dietary recommendations for fermented foods are absent, and only  exist in India and Japan (Marco et al., 2021).

This has still not changed, like it has for probiotics, even with a substantial amount of research and evidence as to why fermented foods should be consumed regularly for health benefits.

Stay tuned for my upcoming article that will take a closer look at a reputable and fascinating study that examines the effects of individuals consuming either a high-fiber diet or a high-fermented food diet, and the distinctive effects these two eating styles had on the microbiome of participants.

Eat well & stay curious until then,

Leeauna Duchesne.

References

Chakrabarti, S., Guha, S., & Majumder, K. (2018). Food-Derived Bioactive Peptides in Human Health: Challenges and Opportunities. Nutrients, 10(11), 1738. https://doi.org/10.3390/nu10111738

De Vrese M, Schrezenmeir J. Probiotics, prebiotics, and synbiotics. Adv Biochem Eng Biotechnol. 2008;111:1-66. doi: 10.1007/10_2008_097. PMID: 18461293

Jäger, R., Mohr, A. E., Carpenter, K. C., Kerksick, C. M., Purpura, M., Moussa, A., Townsend, J. R., Lamprecht, M., West, N. P., Black, K., Gleeson, M., Pyne, D. B., Wells, S. D., Arent, S. M., Smith-Ryan, A. E., Kreider, R. B., Campbell, B. I., Bannock, L., Scheiman, J., Wissent, C. J., … Antonio, J. (2019). International Society of Sports Nutrition Position Stand: Probiotics. Journal of the International Society of Sports Nutrition, 16(1), 62. https://doi.org/10.1186/s12970-019-0329-0

Marco, M. L., Sanders, M. E., Gänzle, M., Arrieta, M. C., Cotter, P. D., De Vuyst, L., Hill, C., Holzapfel, W., Lebeer, S., Merenstein, D., Reid, G., Wolfe, B. E., & Hutkins, R. (2021). The International Scientific Association for Probiotics and Prebiotics (ISAPP) consensus statement on fermented foods. Nature reviews. Gastroenterology & hepatology, 18(3), 196–208. https://doi.org/10.1038/s41575-020-00390-5

Nataraj, B. H., Ali, S. A., Behare, P. V., & Yadav, H. (2020). Postbiotics-parabiotics: the new horizons in microbial biotherapy and functional foods. Microbial cell factories, 19(1), 168. https://doi.org/10.1186/s12934-020-01426-w

Reid, G., Anukam, K., & Koyama, T. (2008). Probiotic products in Canada with clinical evidence: what can gastroenterologists recommend?. Canadian journal of gastroenterology = Journal canadien de gastroenterologie, 22(2), 169–175. https://doi.org/10.1155/2008/843892

Siciliano, R. A., Reale, A., Mazzeo, M. F., Morandi, S., Silvetti, T., & Brasca, M. (2021). Paraprobiotics: A New Perspective for Functional Foods and Nutraceuticals. Nutrients, 13(4), 1225. https://doi.org/10.3390/nu13041225