Scientific Name(s): SCOBY., Symbiotic culture of bacteria and yeast.
Common Name(s): "fungus" Japonicus, Champagne of life, Combucha tea, Dr. Sklenar's kombucha mushroom infusion, Kargasok tea, Kombucha mushroom, Kombucha tea, Kwassan, Manchurian "fungus", Manchurian tea, Pellicle, Spumonto, T'chai from the sea, Teekwass, Tschambucco, Yeast/bacteria fungal symbiont, Zoogleal mat
Medically reviewed by Drugs.com. Last updated on Aug 1, 2019.
Evidence does not support the pharmacologic claims for kombucha teas; case reports of severe toxicity exist.
There is no clinical evidence to support specific dosage recommendations for kombucha.
Use in immune-suppressed patients, and during pregnancy and lactation is not advised.
None well documented.
Cases of nausea and allergic responses have been reported.
Information is limited. Rare case reports of severe toxicity exist.
Kombucha is not a fungus or a mushroom, but rather a cellulose pellicle or mat fermented in a black tea and sugar mix.1 Pellicle is sometimes referred to as a symbiotic colony of bacteria and yeast (SCOBY),2, 3 the bacterial portion of which generally contains Gluconacetobacter xylinus (formerly known as Acetobacter xylinum), that ferments the ethanol produced by the yeast component. Kombucha tea is the resultant sour-tasting, fermented liquid broth, described as resembling sparkling apple cider. Black or green tea has been used, and a number of other beverages, teas (including fruit-based teas), Jerusalem artichoke, milk, and whey, have also been described.1, 4, 5
Kombucha should not be confused with the seaweed konbu (Japanese). See Seaweed monograph.
Kombucha tea has grown rapidly in popularity and has been touted as a miracle cure for a wide variety of illnesses ranging from memory loss to premenstrual syndrome.6
The name "kombucha" is derived from Japanese in that it is brewed in a seaweed (kombu) tea (cha). In Western countries, the product is typically propagated in black tea. Growing spores are floated on the surface of brewed, sweetened black tea, with the mycelium doubling in mass approximately every week. The mass is then divided, and the new portion is propagated on new tea media. In this manner, kombucha mycelium can be propagated at a rapid rate for commercial distribution.7
As the growth matures, it ferments the beverage slightly, which is then consumed for its purported medicinal properties. Consumption of fermented teas has long been popular in Eastern cultures, and the use of this particular mycelial growth may date back several centuries.
Despite extravagant claims for its pharmacologic activity, some experts believe that the tea fulfills the US Food and Drug Administration’s criteria for identifying a fraudulent product, including reference to non-US medical studies, an appeal to personal vanity, ancient origins, and alleged cures for a wide variety of ailments.6 Some of these claims include curing cancer, rheumatism, and intestinal disorders, as well as reversing the effects of aging.
The major bacteria in kombucha are most commonly from the genus Gluconacetobacter, with Acetobacter as the minor or trace bacterium present.5 Other bacteria such as Lactobacillus may also be present.5, 8
Zygosaccharomyces is the likely yeast, but with others such as Candida and Pichia possibly present.9 Standardization issues exist, and the many kombucha teas should be referred to in the plural rather than as kombucha tea (singular).10
The bacteria and yeast together are embedded in a cellulose pellicle, and although symbiosis between the yeast and bacteria has not been proven, a close association is evident.9, 10 The yeast produces ethanol from the sugar, which the bacteria ferments to produce acetic acid, thereby increasing the acidity of the liquid broth. Similarly, the acetic acid appears to stimulate production of ethanol by the yeast, and both ethanol and acetic acid inhibit the growth of other microorganisms.4, 9, 11
Carbon dioxide, acids (gluconic, glucuronic,11 acetic and lactic), phenolic compounds, fructose, sucrose, glucose, minerals, and vitamins (B and C) are also found in kombucha teas.1, 12 With time, the sugar content decreases, and acidity increases to a pH of approximately 2.5.9
Uses and Pharmacology
As the base liquid is generally green or black tea, some of the purported uses may be attributed to the teas themselves.11 See the Green Tea monograph.
Results of a systematic review did not support the use of kombucha teas for cancer prevention or for cancer treatment due to the lack of human studies to support claims and because of the potential risk of serious adverse events.15
Studies in rats have demonstrated decreased liver enzymes and improved creatinine and urea indices with consumption of kombucha teas for up to 30 days. Protection against acetaminophen-, carbon tetrachloride-, and radiation-induced injury has been demonstrated. Antioxidant properties may be responsible for the observed effects.16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27
Due to the presence of phenolic compounds, inhibition of pancreatic alpha-amylase has been postulated, sufficient to cause a net decrease in the absorption of glucose.12
In mice and rats, limited studies have shown that kombucha teas improve lipid profiles and indices of diabetes (glycosylated hemoglobin [HbA1c] and plasma insulin), and well as increasing antioxidant capacity and cardiac markers.16, 29, 30, 31
Studies in rodents have shown that intraperitoneal administration of kombucha teas decreased inflammation and adhesions in induced peritoneal wounds,35 while topical application of the kombucha pellicle resulted in wound healing in rats at a similar rate to that of nitrofurazone ointment.36
There are no clinical data to support the use of kombucha in wound healing, despite the suggested use of the pellicle in burns and as a temporary skin substitute.11
Kombucha teas have demonstrated in vitro antimicrobial activity against bacterial and fungal species, including some human pathogens.4, 9, 37 Antimicrobial activity has been demonstrated even after thermal denaturation4; however, clinical studies are lacking.
Indomethacin-induced gastric ulcers were healed (histological assessment) in rodents with administration of kombucha teas. Despite the acidity of kombucha tea, reduced gastric acid secretion was described.39
There is no clinical evidence to support specific dosage recommendations for kombucha.
Pregnancy / Lactation
Case reports are lacking. Based on chemical studies, inhibition of the angiotensin-converting enzyme may be possible.40
Cases of nausea and allergic responses have been reported.11 Because the final pH of kombucha teas is very acidic (pH 2.5), consumption with water is advised.9 Use in immune-suppressed patients is not advised.1
Rare case reports of severe metabolic acidosis,32, 33 cardiomyopathy,34 and hepatotoxicity28 exist.11, 15, 33 Teas produced under sterile conditions are likely to be safe for consumption, and a food code process for their production has been published.2, 9 Studies in rodents have been conducted. In a 90-day study with oral kombucha, no hematological, biochemical, or histological changes were evident.9 Another study found no evidence of harm to nerve tissue in rats,41 while the internal organs of rats (but not mice) showed lesions in a 12-week study.9
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