Do all Fermented Foods Contain Probiotics?
Although probiotics can be found in certain types of fermented foods, not all fermented foods contain probiotics. Probiotics are defined as “live microorganisms which, when administered in adequate amounts, confer a health benefit on the host.”1 Even if they contain live cultures, very few fermented foods contain microbes that meet the definition of a probiotic. With the rising popularity of probiotics, you may be asking yourself how to include them in your diet. We are here to help you define the difference between the two with a simple side by side comparison.
What are fermented foods?
Fermentation is a process where certain species of bacteria, yeast, or molds break down food components (e.g., sugar) into other products (e.g., alcohol). According to the International Scientific Association for Probiotics and Prebiotics, fermented foods and beverages are “foods made through desired microbial growth and enzymatic conversions of food components”.2 This process can be completed by microorganisms that are naturally present in the food (e.g., sauerkraut, kimchi) or by starter cultures that are added (e.g., kefir, kombucha, natto).
Fermented foods may or may not contain live microbes upon consumption. Some fermented products undergo pasteurization, smoking, baking, or filtering, which destroys the active microbes. For example, leavened bread (bread that contains a small amount of yeast or another leavening agent) is baked after fermentation; and the heat kills any remaining live microorganisms. Other foods that do not contain live microbes after fermentation include beer, wine, sourdough bread, and chocolate. So what fermented foods do contain live microbes? Check out our comparison chart below.
|Fermented foods that are not considered probiotic.||Fermented foods that are considered probiotic.|
● Sourdough bread
● Uncooked Sauerkraut*
|● Some yogurt* (with specific strains)|
● Some kefir* (with specific strains)
Why do only some fermented foods meet the accepted definition of a probiotic?
For a fermented food to be considered probiotic, it must contain a sufficient number of a specific strain of microorganisms that has a direct positive effect on human health, as demonstrated by at least one well-designed human study.3 Although some fermented foods have live microbes in them, e.g. kimchi, sauerkraut, kombucha, their strains have not been defined, and their effect on health is unclear. Since these foods do not meet the criteria stated above, they cannot be labelled as probiotic.
Not all yogurts and fermented milk products such as kefir are considered probiotics either. If they are probiotic, they will identify a specific probiotic strain, which shows demonstrated health benefits such as reducing symptoms of irritable bowel syndrome (IBS) and constipation.
When looking in the grocery store, a fermented product that claims to contain probiotics should display each strain’s designation, though some probiotics sold on the market may also use a simplified trademarked name instead.
Probiotics are known by their genus, species, sometimes subspecies, and strain. For example, for the probiotic bacterium Bifidobacterium animalis subsp. lactis CNCM I-2494, the genus is ‘Bifidobacterium’, the species is ‘animalis’, the subspecies is ‘lactis’ and the strain is ‘CNCM I-2494’.
What are the different health benefits of fermented foods vs probiotics?
Each probiotic is unique, with specific strains that can help specific conditions. Probiotics, when taken in the right dose, can help specific health conditions in the following ways:
- Managing digestive discomfort or IBS symptoms
- Reducing antibiotic-associated diarrhea
- Managing colic in infants
- Digesting fibre and other nutrients
By definition, fermented foods are not required to have a demonstrated health benefit. Nonetheless, fermented foods are a great way to include variety in your diet. The fermentation process improves the taste, texture and digestibility of food. It can also enhance the nutritional value of the food through the synthesis of vitamins and bioactive compounds, as well as the removal of anti-nutritive factors.
Why do the differences matter?
The International Scientific Association of Probiotics and Prebiotic Science (ISAPP) expresses the consequences of calling fermented foods probiotics. Professor Maria Marco, PhD, Department of Food Science and Technology at the University of California writes that mislabelling fermented foods as probiotic makes it difficult to know whether the food has health benefits.4
She adds, “News articles have written that foods like kimchi, sauerkraut made from beets or cabbage, pickles, cottage cheese, olives, bread and chocolate are rich in probiotics. As misuse continues, what becomes of legitimate probiotics shown with rigorous study to benefit health, such as reducing the occurrence and duration of diarrhea? It becomes difficult to understand what strains have scientific proof of benefit. Just as there are laws for standards of food identity, we should try to do the same when describing microbes in fermented foods”.4
Essentially, until the effects of specific microbial strains have been identified, we should simply continue enjoying fermented foods and leave the term probiotics for microorganisms with direct health benefits.
As always, CDHF recommends working with a health care professional if you are looking to add probiotics to your diet to treat a specific ailment.
This resource was made possible due to an unrestricted educational grant from Activia.
- Hill C et al. The International Scientific Association for Probiotics and Prebiotics consensus statement on the scope and appropriate use of the term probiotic. Nat Rev Gastroenterol Hepatol 2014;11(8):506-514.
- Marco ML et al. Sanders ME, Gänzle M, et al. The International Scientific Association for Probiotics and Prebiotics (ISAPP) consensus statement on fermented foods. Nat Rev Gastroenterol Hepatol 2021;18(3):196-208.
- ISAPP position statement on minimum criteria for harmonizing global regulatory approaches for probiotics in foods and supplements; 2018 Oct 9. https://isappscience.org/wp-content/uploads/2018/10/summary-document-probiotics-criteria-ISAPP.pdf
- Marco M. Do fermented foods contain probiotics? International Scientific Association for Probiotics and Prebiotics; 2022 Jan 10. https://isappscience.org/do-fermented-foods-contain-probiotics/