Kombucha - It has a funny name and funny taste, but some serious beneficial health claims surrounding its consumption. Full of probiotics, there are reports out there stating that drinking kombucha can prevent various types of cancer and cardiovascular disease, while promoting liver functions and stimulating the immune system. Pretty bold stuff for a fizzy drink.
Kombucha has gotten pretty popular, and you may have noticed all the different brands and flavours available in stores (I picked up a pumpkin-spice one this fall). It’s even offered “on tap” at some bars/restaurants. But what is it exactly?
Fermentation of sugared tea with a Symbiotic Culture of acetic acid Bacteria and Yeast (SCOBY) is what yields kombucha tea. Its taste is both sweet and acidic, and has the fun fizzy carbonation aspect to it. Kombucha originated in northeast China, around 220 B.C., where it was used for its detoxifying and energizing properties. It was then brought to Japan, to cure the Emperor of his digestive problems. Eventually, kombucha made its way to Russia and eastern Europe, and then to Germany. This is where kombucha got it’s internationally used name – Kombucha is the internationally used Germanized form of the Japanese name. Neat.
Kombucha is prepared by placing the SCOBY into a sugared tea broth for fermentation. Here is where things get tricky when it comes down to the research… there are so many different types of bacteria and yeast used, not to mention different tea varieties, length of fermentation time, amounts of sugar… therefore comes the dispute over the beneficial effects of kombucha. For example – kombucha prepared from green tea produces a higher concentration than kombucha prepared with black tea; fermenting with molasses as the sugar source produces more lactic acid than acetic acid; Gluconic acid isn’t produced until day 6 of fermentation, and the maximum peak varies as fermentation continues.
As well, most of the research that has been done has used animal experimental models, not humans. More research is definitely needed, with more standards in place. But, we can still break it down to see what effects kombucha can have (it’s been around for thousands of years… that means something)
Let’s look at the SCOBY: various acetic acid bacteria: Acetobacter species and Gluconobacter oxydans and yeasts (e.g. Saccharomyces sp., Zygosaccharomyces kombuchaensis, Torulopsis sp., Pichia spp., Brettanomyces sp. and Zygosaccharomyces bailii. Several lactic acid bacteria have also been isolated.
After fermentation, kombucha is a chemical cocktail that includes sugars; tea polyphenols; organic food acids; fiber; ethanol; amino acids including lysine; essential elements such as Copper, Chromium, Iron, Manganese, Nickel, and Zinc; water-soluble vitamins such as vitamin C, and several B vitamins; carbon dioxide; antibiotic substances; and hydrolytic enzymes. That is a lot of stuff!
The acetic acid component of kombucha has antimicrobial effects, and can inhibit the growth of pathogens such as H. pylori, C. albicans, E. coli – to name a few. Acetic acid and catechins are known to inhibit a number of Gram-positive and Gram-negative microorganisms.
Kombucha has antioxidant activity due to the presence of tea polyphelnols, ascorbic acid, and DSL (D‐saccharic acid‐1,4‐lactone produced by Gluconacetobacter sp) . Kombucha tea has shown a higher antioxidant activity than unfermented tea, due to the modification of tea polyphenols produced by the bacteria and yeast during fermentation. Antioxidant activity have many beneficial effects on health, such as: alleviation of inflammation and arthritis, immune enhancement, and cancer prevention.
Tea polyphenols have possible anticancer mechanisms including inhibition of gene mutation, inhibition of cancer-cell proliferation, induction of cancer-cell apoptosis, and termination of metastasis. Anticancer properties of kombucha tea might be due to the presence of tea polyphenols and their degradation products formed during fermentation.
And potential health risks? Home brewers should be aware that there are potential risks associated with a low pH brew leaching heavy metals from containers. Kombucha does contain small amounts of alcohol, so pregnant women, children, those with liver disease, pancreatitis, or in recovery from addictions should not consume this beverage. There have been case reports of hyponatremia, lactic acidosis, and toxic hepatitis, where kombucha has been implicated (but not necessarily confirmed).
My suggestion? Stick to home-brewed kombucha rather than the commercially made ones – KeVita, a popular brand, was actually purchased by PepsiCo – do you think this company has your health in mind? Also, kombucha sold commercially has to be below the 0.5 percent alcohol by volume threshold, but as it sits on the shelf, that alcohol volume can rise as fermentation continues. Commercially made kombucha also needs to be made shelf-stable, and so typically has a higher acid content and/or less varieties of bacteria and yeast, and they are also often pasteurized. This then takes away the reason you’re probably drinking it in the first place! Not to mention the price – as a supplement, this is pretty costly!
Kombucha may not be the magical answer you’re looking for, to cure all your ailments. (Let’s be real… there is no magical answer. Health will not be found in any supplement or food out there – it takes a well rounded, supported approach – reach out to me to learn more). Buying and drinking a kombucha every day will probably clean out your wallet faster than it will clean out your insides. Have kombucha as a part of your diet, in moderation, rotating it with other fermented foods that are full of probiotics and other benefits, such as sauerkraut, kimchi, and kefir. This will expose you to a wide range of effects: polyphenols from tea, different strains of probiotics, fiber from cabbage – etc. Experiment with making these products yourself, enjoy different flavours and varieties, and always remember to look at your health as a whole!
References:
R. Jayabalan, R.V. Malbaša, E.S. Lončar, J.S. Vitas, M. Sathishkumar. A review on kombucha tea-microbiology, composition, fermentation, beneficial effects, toxicity, and tea fungus
Compr Rev Food Sci Food Saf, 13 (4) (2014), pp. 538-550
J.M Kapp, W. Sumner. Kombucha: a systematic review of the empirical evidence of human health benefit. Annals of Epidemiology (30) (2019) pp. 66-70
D. Mackeen. Are there benefits to drinking kombucha? The New York Times. (2019) https://www.nytimes.com/2019/10/16/style/self-care/kombucha-benefits.html