What food has probiotics? What do I need to know about the sources?

We’ve already defined probiotics as live bacteria and yeasts that when consumed confer health benefits on humans, but a couple other definitions are also good to know:

Prebiotics are nondigestible compounds, mostly carbohydrates, that promote the survival and establishment of probiotics in our bodies.

Foods that have prebiotics include asparagus, Jerusalem artichokes, bananas, oatmeal, red wine, honey, maple syrup, and legumes, among many others.

what food has probiotics and prebiotics

Asparagus is rich in prebioc inulin, a nutrient that help probiotics establish and thrive in our bodies.

Synbiotics are the combination of probiotics and prebiotics.

Live, unpasteurized yogurt, kefir, fermented sauerkraut, and kombucha are good examples of synbiotics.

We’ll go into more detail about prebiotics, probiotics, and symbiotics in later blog posts, but for now it’s worth noting that in many studies where they actually have looked at the effect of probiotics alone or probiotics with their prebiotics a greater health affect was often observed with the prebiotics and the probiotics than with only the probiotics. This would support consuming synbiotics like live fermented foods.

So, what food has probiotics? Today you can find probiotics in many, many places. There has been huge growth in the marketing and production of “pure” probiotics or probiotic supplements and you can find pills and little packets of probiotics in the pharmacy or health sections in your supermarkets, but much better still, you can find probiotics in many many fermented products, the list of which is enormous. In a later blog post we’ll go into more detail about fermentation, what it is, and why its so central to a healthy and exciting and sustainable diet, but for this post on probiotics a brief introduction is in order: Humans have been fermenting (using microbes to alter the food) food for millennia. Many many societies throughout human history have developed methods for fermenting everything from milk to pickles to mushrooms to grain to meat to fish to just about any food you can think of. Humans ferment food for many reasons including, and perhaps most importantly, food preservation, but also to make food more nutritious, as well as to make it tastier. As a result, most cultures in the world have evolved with fermented foods. Here in Sweden some of the most common food sources are dairy products like yogurt, kefir, filmjolk, sour cream, and some live cheeses, as well as non dairy products like kombucha, lacto fermented (using bacteria instead of only vinegar) vegetables (ex. Sauerkraut), miso, tempeh, and apple-cider vinager. In addition you can find many newer fermented or probiotic products in the refrigerated section of most supermarkets that are vegetable or fruit based. Generally speaking, any raw (uncooked) fermented product is likely to contain both probiotics and prebiotics, but there is little scientific consensus which ones are best or which ones are best for particular health benefits. Yogurt is, at present by far the most studied, largely due to it’s already widespread consumption, and, perhaps as a result of this, it’s being represented by the largest industry. Research into probiotics has shown that, in addition to them having a number of positive health affects they are A) generally considered safe and B) positive responses to them are often dose dependent (ie. the more pre- and pro-biotics consumed the greater the effect).

What’s all the fuss about probiotics?

Probiotic food and nutritional additives have gained a lot of attention in both research and mainstream media lately. There has been a huge growth in interest in probiotic products over the last 10 years around the world. There is a growing body of evidence to support their importance in our diet; both to treat and prevent specific diseases and as part of a healthy diet. Perhaps unsurprisingly, the global demand for, and production of probiotic products has risen tremendously; to an estimated 32.6 billion US$ in 2014, with a predicted annual increase of 20%. The European market accounts for 42% of this, and dairy products account for 70%. Despite this, the European Union nutritional and health claims regulation adopted in December, 2012 barred the labeling of products as pro-biotic, claiming they are “unauthorized health claims”. This ruling, and these EU regulations have been criticized by many, we believe rightly so, as being overly strict and placing too high a burden of evidence on health claims for which there is in fact a great deal of high-quality scientific support. Before we get into the potential benefits of probiotics and what evidence there is to support those benefits we thought we would take a moment to provide a little bit of background information regarding our digestive system, the human “microbiome”, the term “probiotic” itself, and the history of fermentation and probiotics. This topic is a pretty big can of worms, so while we will do our best to distill the important information, we have to break this post up into a number of sections.


Probiotic products’ are products that contain ‘probiotics’. Definitions of probiotics vary; the word is derived from pro and biota, meaning “for life”. A good definition for the purpose of this blog post is:

Probiotics are live bacteria and yeasts that when consumed confer health benefits on humans.


Acidophulus bacteria in filmjolk consist of different strains, just like the species domesticated dog can does. Many of the positive health effects of probiotics are strain-specific, which is one of the reasons these effects are so complicated to describe.

Bacteria and yeasts (as well as viruses and other single-celled microbes) are naturally found on and in every body. These microbes, which make up the human “microbiome” are so numerous and important that they have even been called our “hidden organ”. Most of these microbes live in our gastro-intestinal tract or “gut” (stomach, large intestines, small intestines colon), but we also have rich microbial communities on our skin and in our mouths, and, for women, in our vaginas; we’ll be focusing on our gut microbes in this post. An estimated 100 trillion microorganisms representing more than 500 different species inhabit every normal, healthy digestive system. In fact, if you count up all these cells, the ones that are in the human body but are not “human” cells, there are 10 times more not human cells in a human body than there are human cells. These microbial communities are very complex and they change in relation to many factors, including if we have taken antibiotics or even if we have a carbohydrate-rich or protein-rich diet, if we are vegetarian or not; in fact, our gut communities change in relation to our diet in as little as 24 hours1. In addition to responding to what food we put into our bodies, the microbes in our gut do A LOT for use. They break down and digest our food into nutrients that we can absorb into our bodies. They also produce important nutrients (vitamins, amino-acids, etc…) that we may not consume in our food. They regulate our immune system and they protect against disease-causing pathogens we may consume orally. These are a few of the many things our gut microbes do for us, and in the proceeding sections of this multi-part blog post on probiotics, as well as in future posts, we’ll go into them in a bit more detail.

The most common types of probiotics are in the bacterial groups (genera) Lactobacillus and Bifidobacterium, but many more exist, and even yeasts (which are fungi) are getting increased attention lately for their potential to confer benefits upon us. One of the tricky things with probiotics is that many positive effects of probiotics are strain-specific, meaning specific bacteria- and yeast-strains do specific things. A “strain” refers to a specific group within a species ex. a golden retriever and a cockerspaniel are two strains of the species domestic dog. As we’ll describe later, this strain specificity of probiotic properties has made research into the health benefits of probiotics and labelling of probiotic microbes much more difficult. In kombucha, the most numerous bacteria are Komagataeibacter sp. (formerly called Gluconacetobacter) and ‘Lactobacillus’, and Acetobacter sp. The most common yeasts are Pichia sp. and Saccharomyces sp 2.

So, if every healthy body contains trillions of helpful microbes anyway, the question is why it is beneficial to consume additional products containing probiotics? One reason to consume probiotic products is to replenish the good bacteria in your guts after e.g. an antibiotic treatment. This has been one of the most common “medical” uses of probiotics; doctors routinely advise patients to eat some live yogurt after a round of antibiotics to help recolonize the GI tract after the antibiotics have potentially killed a lot of the microbes living there. Another reason is to treat a number of diseases that affect us, including chronic diseases like Crohn’s disease, ulcerative colitis, Irritable Bowel syndrome, eczema or viral or bacterial diarrhea. Recent research has also indicated, however, wider ranging potential health benefits of probiotic supplementation including reduced inflammatory responses, reduced allergies, lower blood pressure, weight management, and even cancer prevention. However, the evidence to support these claims is complex and while it is very convincing for some of the aforementioned claims (like treating diarrhea) it is less certain or very preliminary for others. In the following posts on probiotics we’ll go into more detail about the evidence supporting the health benefits of probiotic supplementation, and the consumption of probiotic fermented foods and drinks like kombucha, as well as recent changes in the food labelling laws that affect how probiotic products can be marketed. But first, in the the next post we’ll discuss how to get probiotics and what are good sources of them.



1: Clemente JC, Ursell LK, Parfrey LW, Knight R. 2012. The Impact of the Gut Microbiota on Human Health: An Integrative View. Cell 148: 1258-1266.


2: Marsh AJ, O’Sullivana O, Hill C, Rossa RP, Paul D. Cottera PD. 2014. Sequence-based analysis of the bacterial and fungal compositions of multiple kombucha (tea fungus) samples. Food Microbiology 38: 171-178.


Hello, welcome to Roots Kombucha’s blog, which we have called “Rooted in knowledge”.  Here we are going to write about the knowledge and science behind a lot of the topics we, as brewers, fermenters, and food and drink producers find relevant and interesting. We’re gonna discuss obvious topics like probiotics, fermentation, and microbiology as well as related issues like nutritional research and labeling laws, and maybe anything else we think of that’s interesting.

Our thinking is that “Rooted in knowledge” should be a place to go to get a bit deeper understanding of some important topics that interest a lot of us.  We are often frustrated by how superficial a lot of what’s out there on the web is, oversimplifying complex issues and making huge statements in a brochure-like way, without any evidence to back it up, leaving us wondering how credible they are. Then, on the other extreme you have scientific articles, which are hard to find for most people, hard to access (paywall), and, for many, even harder to read. We want to make this informative, give you the nuances, and hopefully still make it easy to read and interesting. We hope that we can help you better understand and filter the flood of health-related info we are deluged with. Are ginger, turmeric, and lacto-bacteria really that good for me? Why has the EU banned companies from using the term “probiotic”? What’s the difference between “fermented” and “rotten”? What are antioxidants or enzymes, how do they work and should I care? These are a few of the topics we plan on delving into.

Our name “Rooted in knowledge” derives from our pride that what we do, what we produce, what we market, and what we write here, are just that, rooted in science. We started this blog because we think that a lot of customers and friends are interested in the knowledge that we have about fermentation, nutrition, health, and food chemistry and we’re happy to share it, hopefully in nicely sized, entertaining, interesting portions.

When we write “we”, we mainly mean one of Roots Kombucha’s founders, Nicholas Rosenstock. Beyond being a kombucha brewer, Nick has a doctorate in microbiology and is a fermentation fanatic, science-, gardening-, food-, and nutrition-nerd and the personification of the type of person the T-shirt designers had in mind when they printed “Fuck Google…ask me”. He knows, quite simply, a lot, and has a burning desire to spread his knowledge far and wide. Nick’s cofounder Matthias Lehner is also working on this blog as well is their partner Elin Rosenstock.