Kombucha: Studies Show Risks Outweigh Benefits

Kombucha

Proponents of kombucha tea claim the drink, created by certain types of fungi and bacteria that contribute to the fermentation of the tea, has anti-cancer properties and can “detox” the body. Kombucha is a type of black or green tea from the plant Camellia sinensis, that is fermented for about a week,  to which certain types of bacteria, fungi and sugars are added. However, the cumulative scientific evidence as well as studies conducted in the past decade show that kombucha drinks’ risks outweigh their benefits.

According to the American Nutrition Association, kombucha is claimed to have originated in China thousands or hundreds of years ago – depending on the source – and has mystical powers to prolong life and improve health. Some even claim that drinking kombucha can treat AIDS, diabetes, obesity and a host of common diseases and disorders. However, none of these claims have been verified.

Examine.com, an independent research organization that reviews various nutritional topics and trends, recently evaluated kombucha and its claims. Although it is rich in antioxidants, there is no evidence to compare it with catechins found in green tea or vitamin C, which have been proven to help reduce the risk of cancer. Examine.com pointed out that kombucha has saccharolactone, which is a bioactive compound that is claimed to “exert anti-cancer effects in the colon.” Even though studies in rats and in vitro have shown that it may have healing properties, saccharolactone is difficult to apply in human subjects for two reasons: No human studies have ever been done on saccharolactone either in kombucha or by itself, and kombucha intake can increase the risk of death if the drink is prepared improperly. Cross-contamination during the production process can increase the growth of certain bacteria and fungi that may cause “cutaneous anthrax” and “acute renal failure,” according to a few reported case studies. With the given evidence available, Examine.com stated that there is no proven and significant benefit of drinking kombucha nor is it very practical as a health supplement, “considering there’s hardly any evidence for its health effects, but plenty of evidence for the damage it can do.”

Not all animal studies show that kombucha compounds’ benefits outweigh their risks. A study on kombucha’s healing effects on lab rats that was conducted at Tehran University’s Department of Pathology in Iran was published in 2013 in Diagnostic Pathology. Rats that were administered kombucha fungus showed better wound healing than those that were given Nitrofurazone, a type of ointment, but the results and differences “were not significant.”

Scott Gavura, BScPhm, MBA, who is a pharmacist and writer, pointed on Science-Based Medicine to a 2003 systematic review that was published in a Swiss journal
(Forsch Komplementarmed Klass Naturheilkd) that did not find any clinical trials or case series in which kombucha had any hint of medical benefits. “Based on what’s known about the active ingredients, there’s no reason to expect it would offer any medicinal effects other than the consequence of low levels of alcohol or caffeine.” Like Examine.com, Gavura listed documentation of toxicity and harm related to kombucha consumption, including hepatitis and metabolic acidosis.

kombucha
The Kombucha “mother.”

Even though drinking kombucha has risks that outweigh the “benefits,” both Examine.com and Gavura agree that if people like the taste of the product, drink it wisely. Examine.com suggested that consumers purchase kombucha from “trustworthy producers with sanitary working conditions and properly trained staff” to minimize cross-contamination. Gavura said that drinking kombucha “probably won’t kill you.” Considering the lack of documented health benefits, there is no real benefit to consume it unless it is just for the taste. As with any food, Gavura suggested that people should weigh the risks and benefits. In the case of kombucha, it may not be a wise choice for some people.

By Nick Ng

Sources:

Examine.com
Diagnostic Pathology
Forsch Komplementarmed Klass Naturheilkd
Journal of Medicinal Food
American Nutrition Association

11 Responses to "Kombucha: Studies Show Risks Outweigh Benefits"

  1. Petra   November 12, 2016 at 11:41 am

    Why do you say there is no research that would show the benefits? I’m asking because there is. For example an article published a year before you wrote this article. Its called: Effect of Kombucha, a fermented black tea in attenuating oxidative stress mediated tissue damage in alloxan induced diabetic rats. You should check it out.

    Reply
  2. Yogi   September 3, 2014 at 12:36 pm

    You realize that there are no studies to speak on the benefits because big pharm doesn’t want to waste money testing “natural” remedies. They don’t make a profit on things we can make in our kitchen. I do want to point that from someone who did not know of Kombucha before today that your article is extremely negative and one sided. It presents “information” that supports your theory that the risk of drinking is higher than benefits. How much research did you conduct with actual people. People who drink kombucha and believe that there are benefits. How many deaths have occurred….what were the cirumstances? What are the side effects, how many affected? And I should note that you when you site Wikipedia more than once, your argument kind of looses ground.

    Reply
  3. Nick Ng   July 29, 2014 at 5:04 pm

    Thanks, Tabitha. You can evaluate the quality of the health claims by the type of evidence available. Here’s a start.

    http://sourcesandmethods.blogspot.com/2011/05/evaluating-analytic-methods-what-counts.html

    Reply
  4. Brooke Greene   July 29, 2014 at 4:31 pm

    Kombucha is fermented with a colony of bacteria and yeast. There is no fungus involved at all. It would be easier to accept your conclusions if you’d done your research.

    Reply
    • Nick Ng   July 29, 2014 at 4:58 pm

      http://en.wikipedia.org/wiki/Yeast

      Yeast is classified in the Fungi kingdom, thus, it is a type of fungus.

      “Kombucha is a fermented beverage made from tea and sugar, where the addition of inoculum and subsequent fermentation is thought to produce unique health bioactives.[1] This inoculum is commonly referred to as ‘tea fungus’ and contains a mixture of bacteria and fungi which act during the fermentation process. A pellicle which forms during this process is referred to as the ‘fungus’, and the fungus produces Alcohol which helps the bacteria produce the aforementioned bioactives.[2]

      “The tea used is from the Camellia sinensis plant and usually refers to the black tea, although green tea is sometimes used. When black tea is used (as black tea itself requires fermentation to be produced) the final kombucha product is sometimes referred to as being doubly fermented.”

      “The essential organisms that make up the tea “fungus” are an acetic-acid producing strain of bacteria (usually the Acetobacter genus, both and being identified) and yeast.[1] Strains of lactic acid-producting (Lactobacillus) and gluconic acid-producing (Gluconobacter oxydans being identified) bacteria can also be present.[1]

      “There are various yeast fungi that are seen, including Brettanomyces/Dekkera, Candida, Kloeckera, Pichia, Saccharomyces, Saccharomycoides, Shizosaccharomyces, Torulospora and Zygosaccharomyces.[1][3] Although most have been unidentified, up to 163 strains of yeast have been detected,[1] with four major yeasts being Zygosaccharomyces bailii, T.delbrueckii, C.stellata, and S.pombe.[1]

      Although kombucha contains a variety of bacteria and fungi, it appears to be safe for human consumption when properly processed and consumed in moderation (details in the safety and toxicology section).”

      http://examine.com/supplements/Kombucha/

      http://www.ncbi.nlm.nih.gov/pubmed/15282124

      And yes, I had already done my research before writing this.

      Reply
      • sabrina   August 3, 2014 at 6:41 pm

        Then we should all start saying beer is fermented with fungus. I believe your choice to use the word fungus instead of yeast is intended to spin this in a negative way instead of bridging the readers understand to commonly know fermented products. You could simply say that the yeast which are part of the kombucha culture are common beer yeast and the bacteria are ones found in vinegar production as well as yogurt.

        Reply
        • Brooke Greene   August 3, 2014 at 9:12 pm

          Thank you. My thoughts exactly.

          Reply
          • Benito Olamendi   May 25, 2016 at 8:04 am

            This author is trying so hard to discredit Kombucha, while marketing Tyson Chicken on the website and siting Wikipedia as his resources. LOL

        • Nick Ng   August 4, 2014 at 9:34 am

          “Then we should all start saying beer is fermented with fungus. I believe your choice to use the word fungus instead of yeast is intended to spin this in a negative way instead of bridging the readers understand to commonly know fermented products.”

          False. I am stating facts with no intention to “spin” anything in a “negative way.” Your presumption of my motive is a form of ad hominem attack – “poisoning the well.”

          “The next time you hear someone else challenging the motives of another, pay attention it might mean their argument is weak. And the next time you hear yourself challenging the motives of another, consider it a sign that your opinion is probably not as well-formed as you thought.”

          http://betabeat.com/2014/08/dont-poison-the-well-questioning-someones-motives-exposes-your-weak-argument/

          As explained in my previous post, yeast is currently classified in the Fungi kingdom, and the species in Kombucha are from that classification. Here are two examples.

          http://en.wikipedia.org/wiki/Brettanomyces

          http://en.wikipedia.org/wiki/Candida_%28fungus%29

          “You could simply say that the yeast which are part of the kombucha culture are common beer yeast and the bacteria are ones found in vinegar production as well as yogurt.” Perhaps I could have, and it would not change the facts that yeast is a type of fungus.

          There is a difference in how a term is used in language and how one perceives it. The term “fungus” or “fungi” is used as a denotation. While it some people may perceive the word is used as a connotation of their beliefs, sometimes their projection of the usage of the word can be false. Thus, if you have a negative connotation toward a word, then you would perceive it as “negative.” Vice versa, if you have a positive or no connotation of the word, then the perception would be different.

          “Fungus” used here is about the classification of yeast, no different than using the word “bacteria.”

          https://www.csun.edu/~bashforth/098_PDF/06Sep15Connotation_Denotation.pdf

          Reply
  5. Tabitha Farrar   July 28, 2014 at 7:53 pm

    Thank you for a rational and balanced look at this. I have often wondered if the health claims are valid or not.

    Reply
    • Benito Olamendi   May 25, 2016 at 8:05 am

      This author is trying so hard to discredit Kombucha, while marketing Tyson Chicken on the website and siting Wikipedia as his resources. LOL

      Reply

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