Kombucha is the Western name for sweetened tea that has been fermented using a macroscopic solid mass of microorganisms called a kombucha colony.
The culture contains a symbiosis of acetic acid bacteria. The culture itself looks somewhat like a large pancake, and though often called a mushroom, a Mother of vinegar or by the acronym SCOBY (for Symbiotic Colony of Bacteria and Yeast), it is clinically known as a zoogleal mat.
The recorded history of this drink dates back to the Qin Dynasty in China around 250 BC. The Chinese called it the Immortal Health Elixir, because they believed Kombucha balanced the Spleen and Stomach and aided in digestion, allowing the body to focus on healing. Knowledge of kombucha eventually reached Russia and then Eastern Europe around the Early Modern Age, when tea first became affordable to the populace.
The name kombucha is said to have originated in Japan. Reportedly, a Korean physician called Kombu or Kambu treated the Emperor Inyko with the tea. It became known by a combination of the name, Kombu and the word, cha, meaning tea. However, in Japan, kombucha tea is known as kocha kinoko which translates as tea mushroom. Kombu literally means kelp in Japanese and the name Kombucha is used to refer to a hot drink made from powdered kelp.
Kombucha contains many different cultures along with several organic acids, active enzymes, amino acids, and polyphenols. For the home brewer, there is no way to know the amounts of the components unless a sample is sent to a laboratory. The US Food and Drug Administration has no findings on the effects of kombucha. Final kombucha may contain some of the following components depending on the source of the culture: Acetic acid, which provides much anti-microbial activity; butyric acid, gluconic acid, glucuronic acid, lactic acid, malic acid, oxalic acid, usnic acid, as well as some B-vitamins.
Health claims for kombucha focus on a chemical called glucuronic acid, a compound that is used by the liver for detoxification. The idea that glucuronic acid is present in kombucha is based on the observation that glucuronic acid conjugates are increased in the urine after consumption of kombucha.
However, the active component in kombucha is most likely glucaric acid. This compound helps in the elimination of glucuronic acid conjugates that are produced by the liver. When glucuronic acid conjugates are disposed in the bowel during the elimination process, normal gut bacteria can break up these conjugates using an enzyme called beta-glucuronidase. Glucaric acid is an inhibitor of this bacterial enzyme, so the end result is that the glucuronic acid waste is properly eliminated the first time, rather than being reabsorbed and detoxified over and over. Thus, glucaric acid probably makes the liver more efficient.
Interestingly, glucaric acid is commonly found in fruits and vegetables, and is being explored independently as a cancer preventive agent. It has also been discovered that the bacterial beta-glucuronidase enzyme can interfere with proper disposal of a chemotherapeutic agent, and that antibiotics against the gut microbiota can prevent toxicity of some chemotherapy drugs.
Other health claims may be due to the simple acidity of the drink, possibly influencing the production of stomach acids or modifying the communities of microorganisms in the GI tract. For example, anecdotal reports suggest better experience with foods that ‘stick’ going down such as rice or pasta. This is mostly due to relief of stomach gas responsible for preventing proper digestion.