Kombucha

Geschatte leestijd: 6 minuten Kombucha is a sweetened, lightly alcoholic tea that is associated with many health effects. Claims that cannot be substantiated while consumption appears not free of risks.

What is kombucha?

Kombucha, also written as “komboecha” in the Netherlands, is a sweet green or black tea that is fermented. This means that the glucose in the tea is converted into ethanol (alcohol). In kombucha, this is done not only with yeast, but also with the help of acetic acid bacteria. The yeast and acetic acid bacteria form a symbiosis. Together, they form an organism that resembles a jelly-like layer of transparent mushrooms. Somewhat resembling a layer of mold that can form in a glass of drink and thus form a floating layer on top of the drink. This creates a lightly alcoholic, lightly sparkling drink.

Kocha kinoko instead of Kombucha

When we translate words from Japanese into the Latin alphabet, things can quickly go wrong. Even if only because of the need to determine the Latin spelling phonetically (based on the sound). We cannot look at the original spelling given the three Japanese scripts hiragana, katakana, and kanji tell us nothing. This, of course, leads to mistakes in translations. Kombu-cha (or however you want to spell it) is actually a drink made from kelp. A very different drink that is not fermented and therefore does not contain alcohol.

昆布 = kombu = kelp 
お茶 = ocha  = tea

The term that Japanese people use for what we call kombucha tea is actually kocha kinoko.

Kombucha tea

The layer formed by the symbiosis of yeast and acetic acid bacteria, often called mushroom or tea fungus, is often called kombucha itself. So when we talk about ‘kombucha,’ it is important to make a clear distinction between this symbiosis itself and the tea made with it.

What is kombucha good for?

If you tend to put kombucha in the same category as things like nettle tea or ginseng, that’s not strange. All examples of remedies that your grandmother would advise for complaints from headaches to heartache. That’s not to say that such remedies cannot have positive effects on health, but that these effects are often exaggerated. Thus, the lightly alcoholic tea is often associated with preventing or curing cancer. Personally, I have great difficulty with people who make unsubstantiated claims regarding the prevention or cure of (the various forms of) cancer. My Jomanda-Millecam alarm immediately starts ringing when I read various non-scientific sources about kombucha.

What is kombucha good for according to users?

If we are to believe tradition, then with kombucha we can almost achieve world peace [1,2,3]. Why, for example, use a cocktail of drugs to slow the effects of AIDS when you can cure it with kombucha [4]? And why do we make such a fuss about cancer when the Japanese apparently already have a solution in the form of this tea? Anorexia, aging, diabetes, rheumatism, kombucha doesn’t shy away from it. These are just some of the claims about kombucha as revealed in a systemic review from 2000 [4]. Not impressed yet? Kombucha could also cure asthma, herpes, insomnia, diarrhea, and cataracts. What about shrinking the prostate and increasing libido? Why buy a facial cream when you can get rid of your wrinkles with this tea? Why dye your hair when you can get rid of your gray hair by drinking kombucha? What’s your excuse for having hemorrhoids or high blood pressure when it’s so easy to remedy with a few sips of this oriental delicacy?

What is kombucha good for according to science?

Your excuse, of course, is that you have a set of working brains and possess a reasonable bullshit radar. If someone makes certain claims to you about the health effects of a product, your standard answer is: And we’re not talking about studies conducted with petri dishes (in vitro) or animals [5,6]. Unfortunately, however, no trials have been conducted with humans that could substantiate any of the above claims [2,3,5]. Researchers from the Universities of Exeter and Plymouth conducted a systemic review in 2003 of the alleged effects and the actual effects [1]. They concluded that the tea was an “extreme example” of alternative medicine due to the large difference between the large number of health claims and their diversity versus the effects and risks as established in research. The researchers therefore concluded that the unsubstantiated claims do not outweigh the known risks of kombucha. The tea should not be recommended for therapeutic use.

According to the researchers, kombucha only works therapeutically for the person who sells it.

Or as a Japanese person would say: “Kombucha wa totemo baka desu!” (freely translated: “kombucha is complete bullshit”)

Is kombucha dangerous?

Let’s further delve into those known risks. Death from kombucha is one of the serious yet rare side effects of kombucha, presumably caused by contamination when the drink is made at home [7,8]. Because the drink is often homemade and uses fermentation, disease-causing microorganisms can contaminate the tea [5]. Think of other serious side effects including severe liver and kidney damage, but also metabolic acidosis (“blood acidification”) [9,10,11]. Such acidification and associated effects should be prevented by fermenting the drink too long [14,15]. At least one case of death has been associated with drinking kombucha, although it could not be proven that the drink was the (sole) cause of death [12,13].

Contaminated kombucha

As mentioned, there is a risk of contamination during the production process. Think of unwanted bacteria, among other things. In one case, there was even anthrax infection due to local administration of kombucha [1]. However, the tea could be contaminated during storage in this case. People with a weakened immune system are warned against using kombucha. The same advice applies to people with existing medical conditions, pregnant women (and women who are breastfeeding), and children under 4 years of age [7,16,17]. Also, consideration should be given to the low alcohol content of the tea when using certain medications [18]. A review from 2019 confirms the large number of potential negative health effects. Nevertheless, according to the researchers, use is safe at dosages of up to 113 grams per day by healthy individuals. These researchers also point to possible acidification and leaching of heavy metals from the packaging.

Is kombucha banned?

The IOCOB Foundation evaluates alternative medicines and classified kombucha in the category of ‘quackery’. In 2000 and 2003, the researchers advised against the use of the tea due to the potential risks [19]. In Belgium, they went further and banned the sale of medicines based on kombucha [20].

Fear mongering?

Not exactly a positive conclusion here. Health effects that cannot be demonstrated while there are considerable concerns about side effects. I noticed that the decision of IOCOB was followed by rather angry reactions from (apparently) kombucha fans. They accuse IOCOB, among other things, of attributing side effects that can also occur with other medical and food products. For example, a reader refers to a study (on rats) mentioned by IOCOB in the references, which showed that no poisoning occurred. Another points out that any risks are mainly caused by errors during production. It can be argued that the evidence for the mentioned risks is thinner than the evidence for side effects of commonly used medication. However, the point is that you can expect that medication to actually have the intended positive effect on health. If you can question the positive effects of kombucha, why would you take the risk of adverse side effects? If you just find it a very tasty drink, then that’s a different consideration. However, don’t expect to be protected against cancer or AIDS now.

References

1. Ernst E (2003). “Kombucha: a systematic review of the clinical evidence”. Forschende Komplementärmedizin und Klassische Naturheilkunde. 10 (2): 85–87. doi:10.1159/000071667. PMID 12808367.
2. Bauer, Brent (July 8, 2017). “What is kombucha tea? Does it have any health benefits?”. Mayo Clinic. Retrieved 2018-09-05.
3. Jayabalan, Rasu (21 June 2014). “A Review on Kombucha Tea—Microbiology, Composition, Fermentation, Beneficial Effects, Toxicity, and Tea Fungus”. Comprehensive Reviews in Food Science and Food Safety. 13 (4): 538–550. doi:10.1111/1541-4337.12073.
4. Jarrell J, Cal T, Bennett JW (2000). “The Kombucha Consortia of yeasts and bacteria”. Mycologist. 14 (4): 166–170. doi:10.1016/S0269-915X(00)80034-8.
5. Villarreal-Soto, Silvia Alejandra; Beaufort, Sandra; Bouajila, Jalloul; Souchard, Jean-Pierre; Taillandier, Patricia (2018). “Understanding Kombucha Tea Fermentation: A Review”. Journal of Food Science. 83(3): 580–588. doi:10.1111/1750-3841.14068. ISSN 0022-1147. PMID 29508944.
6. Kapp JM, Sumner W (February 2019). “Kombucha: a systematic review of the empirical evidence of human health benefit”. Ann Epidemiol. 30: 66–70.
7. https://www.sciencedirect.com/science/article/pii/S1047279718307385?via%3Dihub
8. “Kombucha”. www.mskcc.org. Memorial Sloan Kettering Cancer Center. 22 May 2014. Retrieved 2017-04-10.
9. Russell J, Rovere A, eds. (2009). “Kombucha Tea”. American Cancer Society Complete Guide to Complementary and Alternative Cancer Therapies (2nd ed.). American Cancer Society. pp. 629–633. ISBN 9780944235713. Serious side effects and occasional deaths have been associated with drinking Kombucha tea.
10. Dasgupta, Amitava (2013). “Effects of herbal remedies on clinical laboratory tests”. In Dasgupta, Amitava; Sepulveda, Jorge L. (eds.). Accurate Results in the Clinical Laboratory: A Guide to Error Detection and Correction. Amsterdam, NH: Elsevier. pp. 78–79. ISBN 978-0-1241-5783-5.
11. Dasgupta, Amitava (2011). Effects of Herbal Supplements on Clinical Laboratory Test Results. Berlin, Germany: Walter de Gruyter. pp. 24, 108, 112. ISBN 978-3-1102-4561-5.
12. Abdualmjid, Reem J; Sergi, Consolato (2013). “Hepatotoxic Botanicals—An Evidence-based Systematic Review”. Journal of Pharmacy & Pharmaceutical Sciences. 16 (3): 376–404. doi:10.18433/J36G6X. PMID 24021288.
13. Bryant BJ, Knights KM (2011). Chapter 3: Over-the-counter Drugs and Complementary Therapies. Pharmacology for Health Professionals (3rd ed.). Elsevier Australia. p. 78. ISBN 978-0-7295-3929-6.
14. Unexplained Severe Illness Possibly Associated with Consumption of Kombucha Tea — Iowa, 1995 (Report). Morbidity and Mortality Weekly Report. 44. CDC. 8 December 1995. pp. 892–893, 899–900. Retrieved 18 July 2015.
15. Kombucha”. Memorial Sloan Kettering Cancer Center. 22 May 2014. Retrieved 1 June 2015.
16. Nummer, Brian A. (November 2013). “Kombucha Brewing Under the Food and Drug Administration Model Food Code: Risk Analysis and Processing Guidance”. Journal of Environmental Health. 76 (4): 8–11. PMID 24341155.
17. Greenwalt, C. J.; Steinkraus, K. H.; Ledford, R. A. (2000). “Kombucha, the Fermented Tea: Microbiology, Composition, and Claimed Health Effects”. Journal of Food Protection. 63 (7): 976–981. doi:10.4315/0362-028X-63.7.976. ISSN 0362-028X. PMID 10914673.
18. Food Safety Assessment of Kombucha Tea Recipe and Food Safety Plan(PDF) (Report). Food Issue, Notes From the Field. British Columbia (BC) Centre for Disease Control. 27 January 2015. Retrieved 1 July 2015.
19. Martini, Nataly (March 2018). “Potion or Poison? Kombucha”. Journal of Primary Health Care. 10 (1): 13.
20. iocob.nl/2005/12/kombucha/
21. ejustice.just.fgov.be/mopdf/2000/12/07_2.pdf#Page1