It seems simple right? A kombucha scoby is by definition a symbiotic culture of bacteria and yeast. It certainly does have bacteria and yeast, so of course it must have probiotics right?
The surprising answer is that experts are not really sure if it does have probiotics or not.
I was recently in Australia attending a fermentation workshop where Kriben Govender of nourishmeorganics told everyone that the only real probiotic in kombucha may be a yeast. And that yeast is still a question.
That took me by surprise. I knew that kombucha was not known for probiotics like kefir is; however, I believed (like most people do) that its still fairly rich in probiotics in its natural form. The more I delved deeper, the more I realized that kombucha, although extremely powerful and health-giving, is not really a probiotic.
What exactly is a probiotic?
The word probiotic comes from the Greek word pro, which means “promoting” and biotics, which means “life”. So basically, it means “promoting life”. It’s more than just bacteria or yeast, its bacteria and yeast that when consumed is beneficial in some way. Typically when you think of probiotics you think of bacteria such lactobacillus or bifidoabcteria. Yeast can be probiotic too, but its much less studied. The main reason lactobacillus and bifidobacteria are considered probiotic is because they are quite abundant within the human intestines. When ingested, the live bacteria have at least transient (temporary) benefits.
The bacteria in kombucha is acetic acid bacteria. It’s different to lactic acid bacteria that ferments veggies and kefir.
Lactic acid bacteria is probiotic in nature; whereas acetic acid bacteria is not.
Why is acetic acid bacteria NOT probiotic?
Anyone who has done kombucha knows that it requires an open lid. Kombucha is powered by acetic acid bacteria and they will not survive long term with a closed lid or airlock.
The human body most likely does not have any acetic acid bacteria within the body according to one large study. The main reason is because acetic acid bacteria requires access to oxygen to survive and obviously oxygen is in short supply in the intestinal tract. Lactic acid bacteria (kefir probiotics) does perfectly fine without oxygen. Studies on the intestinal tract, oral cavity and skin show no acetic acid bacteria. The oral cavity and skin do have oxygen, but they don't seem to be present there either.
So as far as the human body is concerned, live acetic acid bacteria is most likely not probiotic.
Is the yeast probiotic?
Perhaps the only probiotic in kombucha is actually the yeast. When we hear yeast, we may think infection, candida, and all sorts of bad things. But some live yeasts that are consumed in moderation are beneficial and may be considered probiotic in nature.
Saccharomyces cerevisiae which is one of the more common yeast strains in kombucha has been extensively tested to have probiotic properties. It’s shown to help inflammatory bowl disease and several types of diarrhea. Other similar yeast strains may also be probiotic.
Unfortunately there’s not a lot of live yeast in a typical kombucha brew once its done.
The reason is because of the very low pH level. The average pH is 3.2 to 2.5 when consumed. The acetic acid bacteria is designed to survive with acid, however the yeast struggles. Yeast like acidic environments and are quite resistant to acid, but at that low of a pH, it too starts to die off.
So in the end you likely get some measure of yeast, but its quite minimal when compared to kefir and other ferments.
What about commercially made kombucha?
Funny enough the new companies are starting to add probiotics to kombucha after production, which may be more than what you get with homemade kombucha. So would I advocate commercial kombucha over homemade kombucha? Absolutely not.
I had the opportunity one time to visit a factory where commercial kombucha is made. They admitted that they did all sorts of things to the culture to suppress its natural fermentation. Especially the yeast side of things as they were concerned about CO2 and alcohol. The end product was just not that appealing, so they end up doing a force carbonation because it’s so dead and add flavors and fake sugars to make it taste right. If you’ve ever tried home-made kombucha, there’s nothing you need to add.
Kombucha is delicious and has many health benefits, but it may not actually be a probiotic like kefir. The acetic acid bacteria is not really probiotic for the human body and the yeast is fairly minimal because the typical kombucha ferment has such a low pH.
Some people might question if there's a point to consuming kombucha with such minimal probiotics. I strongly believe there is. Kombucha is known to have many health benefits irrespective of any live probiotics. Homemade sourdough is cooked and has no live probiotics, but its still incredibly healthy. Healthy foods that are beneficial to the gut come in many forms.
If you are truly looking for probiotics, then milk kefir, water kefir and ginger beer are better options.
I believe the point of kombucha is not the probiotics. It's everything else in it. It also compliments kefir quite well due to the inherent differences.
Like most things in life, diversity is key.