Kombucha: Healthy or Harmful?


By Revital Aranbaev

Kombucha is a fermented tea that has gained lots of popularity and a substantial following in recent years. Many people drink for its assumed medicinal benefits; it is most commonly known for boosting the body’s immune system. Some say the drink can work miracles with benefits including curing baldness, detoxifying the body, repairing joints, curing cancer, reducing blood pressure and prolonging life.

It is said that kombucha originated in ancient China and was used as a health tonic for thousands of years, but various forms of fermented tea exist in other countries as well. Since the 19th century, fermented tea was used in Russia; they referred to it as "tea kvass."

Kombucha is a SCOBY – symbiotic culture of bacteria and yeasts. It is a fermented drink made with tea (usually green or black), sugar, bacteria and yeast. Even though it's often referred to as kombucha mushroom tea, kombucha is not a mushroom; it's a colony of bacteria and yeast. The natural, vegan beverage contains organic acids, B vitamins, amino acids, polyphenols, enzymes, probiotics and traces of ethyl alcohol, depending on brewing time and conditions.[i] 

In order to make kombucha, brewers rely on what’s called a starter – a bit of already fermented tea- referred to as “the mother.” Once the mother is added to sweetened tea and allowed to sit in a glass jar unrefrigerated for 7-14 days, a colony of bacteria and yeast grows above the surface. This “mother” will expand and split into smaller pieces termed “babies,” which brewers can give to friends or sell. [ii]

Though Kombucha has had a rise in the last few years it is the second wave of its popularity. The first wave was in the early 1990s when it was thought to boost immunity in people with HIV/AIDS. At that time it wasn’t as readily available.

In 1995, the Centers for Disease Control and Prevention (CDC) issued a report linking kombucha to the death of a woman and the illness of another woman. Both women experienced excessive acid buildup in the body that health professionals correlated to their daily dose of kombucha. The center did not definitively cite the tea as the culprit but the incident made people hesitant to make kombucha a part of their daily lives.

In 2003-2004 the slightly fizzy, sour & sweet drink- Kombucha made its return. At that time Whole Foods began distributing the tea nationally. In 2009, kombucha and other “functional” juices in the United States topped $295 million that year, according to SPINS Inc., a market researcher.

Kombucha’s popularity was growing as a part of a larger trend in “probiotic” foods containing bacteria, which some studies suggest benefit digestion and boost the immune system.

Studies assessing the benefits of kombucha involving humans are lacking; all studies available have been done with animals. It is good to note though that there have been numerous individual accounts that Kombucha has helped people with digestion, arthritis and even cancer.

In an interview by the Pittsburgh Post Gazette in 2007, commercial kombucha brewer G.T. Dave, credited kombucha for possibly slowing the spread of an aggressive form of breast cancer that his mother dealt with and for keeping up her strength and spirit during chemotherapy.[iii] The experience sparked her teenage son's interest and later his business. 

Research has shown that kombucha may have anti-microbial effects against harmful bacteria like E. coli. A Serbian study published in 2007 looked into combining Kombucha with other herbs. The study demonstrated that lemon balm kombucha showed strong antimicrobial effects against E. coli and Salmonella bacteria and it inhibited the growth of Staphylococcus aureus. It was shown that kombucha made from lemon balm tea had higher antioxidant activity than lemon balm tea alone, probably due to vitamins added by the fermentation process.[iv]

Promoters of kombucha also claim it protects the liver from damage. An Indian study done on animals in 2009, gave carbon tetrachloride to induce liver damage and then assessed the impact of kombucha tea along with black tea and enzyme-processed tea. Researchers found that kombucha tea had more protective effects than the other two teas.[v]

Kombucha “has prophylactic and therapeutic properties” including antimicrobial, antibacterial, and antifungal effects, according to a study destined for the June 2012 issue of Swiss Society of Food Science and Technology. Its authors state that kombucha “may be very healthful” in combating yeast infections, thrush, and other forms of candidiasis.[vi]

Unfortunately there aren’t too many studies that help asses all of the benefits that people connect to drinking Kombucha. Scientific evidence on kombucha’s benefits is just in the preliminary stages but there are numerous individual testimonials from people who drink kombucha reporting benefits like enhanced wellbeing, increased energy and weight loss and many other benefits. 

Some medical professionals, however, think the drink is dangerous. According to Dr. Michael Gregor, a physician, author, and internationally recognized  speaker, Kombucha may be harmful to your health. Published last year, the journal of Intensive Care Medicine states that, “kombucha may cause serious health risks and consumption of this tea should be discouraged.”

Renowned doctor, Andrew Weil is concerned with the same health risk that Dr. Gregor mentions, lactic acidosis (the build-up of lactic acid). According to Dr. Weil’s article, physicians at Cedars-Sinai Hospital in Los Angeles reported a life-threatening case of lactic acidosis and acute kidney failure in a 22-year-old man newly diagnosed with HIV within a few hours of his consuming kombucha tea. This happened in 2009. Dr. Weil specifically warns pregnant women, nursing mothers, the elderly, children and anyone with a compromised immune system against consuming it.

Dr. Weil is concerned with the possibility of contamination in home-brewed kombucha. “Some batches contain aspergillus, a toxin-producing fungus. This would be a significant risk for individuals with compromised immune systems, such as those with AIDS or in chemotherapy for cancer. There have been reports in the medical literature of adverse reactions, including nausea, vomiting and headaches, in people drinking more than four ounces of kombucha tea daily.”[vii]

The U.S. Food and Drug Administration also noted that the potential for contamination of kombucha tea is high because the teas are often brewed in homes in non-sterile environments. Plus if kombucha tea is brewed in ceramic pots, the acids in the tea may pull lead from the ceramic material which would lead to lead poisoning.[viii] 

Dr. Weil says that he knows of no health benefits from Kombucha. He also adds that kombucha has become extremely popular, in part due to photos of celebrities such as Lindsay Lohan and Halle Berry carrying bottles of the beverage and in part by promotion of the idea that it's a healthy drink.

Lastly, the American Cancer Society states that available scientific evidence does not support any claims that Kombucha tea can promote good health or prevent the development of certain ailments. The scientific studies that involve Kombucha tea are based on lab reports and animal findings, and reported benefits are based on personal reports.[ix]

It seems as if the arguments both ways could benefit from more substantial evidence and studies. Do you drink Kombucha tea? Please post your comments.

25 Comment(s)

  1. Yes and I make my own….

    Mark | Reply

  2. I do drink Kambucha. I have done a lot of research on it and I believe that it is beneficial for the immune system. Since I started drinking kambucha, I wake up earlier and feel more energetic. I am very health conscious and highly aware of the subtle queues my body gives me. I do understand that kambucha would not be best for all people – that is why each individual interested in drinking kambucha should do their research and give it a try before they regularly drink it.

    Gal | Reply

  3. I drink kombucha daily.  Since I started drinking it my GURD has gone away.  I have not been sick when everyone around me has been sick with the flu.   I have no heartburn problems, my bleeding ulcer has healed, my arthritis has improved, I have only had one migraine in 18 months versus having 2 or 3 a month before, and I feel better overall.  Maybe if just one of those things had happened it could be a coincidence but not all of them.  I beleive kombucha has helped my body heal naturally and I will continue to drink it daily.  I enjoy not taking all of the "modern" medicines I needed before and feeling better than I have in years.

    Jan | Reply

  4. Funny how a few dramatic instances of a "natural" health product can be blown up to huge proportions, yet thousands of people a year dying from one properly prescribed pharmaceutical gets pooh poohed into oblivion and those bringing up the statistics are discredited as quickly as possible.  Being aware of ones body and doing anything in moderation is key.  I he made my own Kombucha for over two years now.  I drink about 48 oz. per week.  I like it.  I can't say I have had huge benefits from it, but I know it has done far less harm than a soda or manufactured energy drink to my body.

    Bryan | Reply

  5. thanks trevor.  i like the taste of this tea, though i suspected, that like other grain-based asian & japanese teas – they are not so great for people who have a tendency towards candida or other immune related inbalances.  if your diet is very alkaline, well then maybe the B viatmins are bioavailable, but if not – probably better to take a B vitamin supplement.  p.s. i would be very interested in a blog about nutritional yeast as i understand that its a way for vegans to ingest a little more Vitamin B12;  yet a vegan friend warned me about the possibility of a skin rash developing – all yeast related, i suspect:  though apparently nutritional yeast doesn't contain yeast that actually rises?

    Melissa | Reply

  6. I too love Kombucha but after reading how it is made I stopped drinking so much. There is so much sugar in it and I already have issues with sugar and my health so it's not a good drink. My friend made some at home, it tasted good but again it makes me scared to drink a home brew after reading this and knowing how much sugar she put in it. 

    Stephanie | Reply

  7. I occasionally enjoy G.T. Dave Kombucha, particularly the gingerade flavor. However, I do not brew it at home.

    Zyxomma | Reply

  8. Thank you for the article! I have personally benefited from Kombucha. I am a person with severe asthma and compromised immune system. My digestion was virtually non-existant due to my illness and years of medication (I had terrible stomach and esophageal damage). Kombucha changed that and a lot more. I would be very concerned with making it at home unless I was an expert.   However, I make my judgments based on tried and true philosophy such as that of ancient medicines used in old cultures like Chinese medicine and it has worked for me so far. China and Russia are very old cultures and have greater success rates with illness treatments. If you are like me, you understand that it is the modern culture that often makes us sick and unable to overcome some of the simple issues previous generations have.

    Nia | Reply

  9. Hi Trevor, and thanks for the article.  I brew Kombucha at home and don't find it more dangerous than making your own yogurt.  We know we have to be very sanitary with fermented products – end of story.  I like the taste and have not experienced any problems with drinking between 4 and 8 ounces daily.  I use it in my green smoothies in the morning as well.  Given the choice between eating processed food which many doctors eat every day (I am an RN), and drinking Kombucha, I'll take the fermented tea – hands down.

    Linda | Reply

  10. I have made kombucha at home, in clean glass jars. I like it a lot. I don't drink it every day. Everything in moderation. I also don't like Dr. Andrew Weil. For a doctor who is allegedly "holistic" or whatever he considers himself, be is always knocking things. Sounds more like a typical Western medical dr to me. He is against colonics. Maybe he should try it before he knocks it. We all know disease starts with a toxic colon.

    Ida | Reply

  11. I have been brewing Kombucha at home for about six months and find a huge difference in my digestion and energy levels. I am also eating homemade fermented foods….I am sure there is a lot to be said against this as well. I think everything in moderation and to each their own. If it doesn't feel right to you then don't do it. Your body will tell you, just listen to it.

    Audrey | Reply

  12. Thank you for sharing this.

    Cynthia Morris | Reply

  13. I personally enjoy the occasional kombucha as a pleasant alternative to alcohol at social gatherings – people are often curious about it and it sparks great conversations. I also like it as an alternative to pop.
    I have a few friend who make their own kombucha and they say that it's very easy to tell if the mother or the batch has gone "off", but nonetheless, I wouldn't want to brew my own and don't trust the home brewed stuff as much.
    It seems wise to avoid if someone has a yeast issue.
    To answer Melissa – Nutritional yeast is pasteurized (which kills the bacteria) and tested to contain no live yeast cultures. I

    Nadine | Reply

  14. I'm sorry, but five of the sources are from Livestrong, which often includes bloggers approved at random to write articles. Although all other sources are credible, it forces me to take this review with a grain of salt…I don't mean to offend you, but when providing the public with information, especially in regards to health, it's truly important to be sure all the facts are correct (which they may or may not be in this case). I always encourage my clients to do their homework before making any major decisions about raw foods and health. Please be more careful in the future.

    Purna | Reply

  15. Melissa,
    As a nutritional consultant I can assure you that b-vitamins (aside from B12 which is not in kombucha in any event) are easy to get from a healthy diet including fresh fruits and vegetables. While I recommend my clients to take probiotic supplements (in pill form), B12 (in the methyl form) and vitamin D (as D2), I never recommend taking any other supplements. Often it is a waste of money since the nutrition can not be absorbed. Sometimes it is harmful, as some supplements contain "vitamins" that are not actually what is found in nature. For example, ascorbic acid is not the same as the vitamin C complex in nature — it is just a small part of the vitamin C complex, and acting alone it can be harmful in large doses, whereas you can't overdose on the real vitamin C found in fruits and vegetables.
    The only reason to drink kombucha for health, thereby, would be for its probiotic content. If it did contain harmful molds then it would also contain harmful mold wastes, and that is very, very serious. The toxins created by mold are what make cheese and peanuts so unhealthy (and why so many people suffer an intolerance or allergy to these foods).
    I like the taste of kombucha, but I only buy it on occasion, and I don't brew it as of yet because I'm not 100% positive how to ensure what probiotics I end up brewing. Also, I'd want to be completely certain that all the sugar is eaten by bacteria as I wouldn't want to consume any sugar.
    ~ Raederle Phoenix

    Raederle | Reply

  16. Purna,
    I completely understand your concern. I can assure you that I don’t simply use blog stats, actually if you take a look closer to which articles I’ve included, the 1st on is a simple description of Kombucha and it’s benefits, which you can easily find from other sources as well. Three of the other livestrong articles I cited, I am not actually citing the article but the study that the article mentioned. If you would open up those three livestrong articles you would see their citations are published studies. And the final livestrong article I cited was a quote from the Food and Drug Administration.

    admin | Reply

  17. Thank you for the article Trevor.  I learned some new sides to the equation with this drink.  I had actually attended a kombucha preparation class a few years back in nyc and had begun making my own drink in glass mason jars.   It was quite a timely process and eventually I ceased to prepare it and opted to buy it at the store.  
    However- when I got diagnosed with candida amongst other things from my holistic doctor she warned me about drinking kombucha noting all her patients fed the yeast further drinking it and advised me to not drink it.   So I'm sure there is some truth to your arguments.

    sara | Reply

  18. Kombucha is NOT a grain-based tea.

    Candace | Reply

  19. Great article and very timely.  I had a yeast infection yesterday, and knowing nothing about kombucha's supposed helpful properties for yeast infection, drank one I'd bought from the natural food store.  The burning sensation was gone within a couple of hours.  Then I read your article!  I agree with the man above who posted about how we make such a big deal out of the possible health risks for natural products, but very little is done about those who are getting sick and dying daily from pharmaceuticals, junk food, and food made from animals and animal secretions.
    As usual, great work Trevor.

    Mary | Reply

  20. I am unfamiliar with such a tea however it appears to be far too much trouble to make and has negligible benefits. And if acidosis is a related problem, the majority of the public have too much acid in their systems already, so why add more.

    Gerry Coffey | Reply

  21. I drank Kombucha and it made me drunk. I'm serious. I did some research and found out its made from white, refined sugar!  Its not healthy at all, its simply a fad. Snake oil.

    nomorekombucha4me | Reply

  22. Different kombuchas have different culture blends, different levels of sweetness and different levels of alcohol. Home-made brews can even come out with dangerous blends if the maker is inexperienced. The white sugar is entirely fermented in most brews. Personally, if it isn't entirely fermented until all of the sugar has been consumed by the cultures, it tastes bad to me.

    Raederle Phoenix | Reply

  23. a freeind who said to me that kombucha,,is a yeast and that i should stop drinking and brewing it for that reason,,he says my body is showing an overproduction of yeast,,gummy and itchy eyes,,and that the sugar could be exacerbating this condition,,,im al confused now cause ive been brewing and drinking for nearly ayear i like it,,and this year i have for the first time in years been waking up early every morning and dont get tired from that during the day,,,i sleep very well at night,,as i was experiencing night sweats before i started using it,,,any advise???

    paul | Reply

  24. Hi, i am from india and iam vegan. Would like to know is it vegitarian or not. Thanks

    Srinivas | Reply

  25. Hi Srinivas – the kombucha “mushroom” is made up of bacteria and yeast, but you’re drinking the tea, not the yeast, so yes, I’d say it’s vegan. It depends on how far your personal definition of “vegan” goes. Most vegans avoid insects, like honey from bees, but I’ve not heard of a vegan avoiding yeast-fermented drinks. If you drink or eat other fermented dishes like water kefir or sauerkraut, then it’s fine for you to drink kombuchu.

    Val Archer | Reply

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