Alison Dalton, BA, BS, MS - Kombucha
Kombucha is the health drink of the moment. Big claims are made for it by its fans and brewers, who say the slightly fizzy, sour-sweet drink can work miracles: boost energy, restore hair growth, detoxify your body, repair joints, cure cancer, prolong life (and those are just a few of the claims). On the con side, kombucha has likely been responsible for at least one death. (So much for prolonging life.)
With that in mind, let’s take a closer look at kombucha.
What is kombucha, anyway?
Kombucha is fermented tea. It’s made by culturing a symbiotic mass of yeast and bacteria in sweetened black or green tea.
How long has it been around?
The legend is that kombucha originated in ancient China, but there’s really no way of knowing if the wondrous tea referred to in Chinese literature was really kombucha. In any case, various forms of fermented tea have existed in many cultures for centuries. Kombucha has been consumed in Russia, where it’s referred to as “tea kvass,” since at least the 19th century. The drink also had an earlier moment in the US in the 90s, when it was thought it could boost immunity in people with HIV/AIDS.
How does kombucha fermentation work?
Kombucha fermentation depends on the “mother”—the culture, a leathery mat that floats on top of the tea like a thick pancake. The mother consists mainly of strains of acetic acid bacteria and one or more strains of yeast. The bacteria break down the sugar in the sweetened tea. The yeasts produce alcohol from the resultant sugars, and the bacteria produce acetic acid (vinegar) from the alcohol. Hence, kombucha contains a slight amount of alcohol—from 0.5% to 1.5%, below the level that would require it to be classified as an alcoholic beverage.
The mother gives rise to smaller cultures, called babies. Babies are often sold, traded, or given away by kombucha brewers.
Is kombucha good for you?
Maybe. Kombucha is a probiotic brew, meaning it contains microorganisms that may boost your immune system and assist in maintaining a healthy balance of intestinal flora. Although these organisms are beneficial for most people, they may be dangerous for people with serious illnesses or compromised immune systems.
In addition to acetic acid and alcohol, kombucha may also contain butyric acid, B vitamins, gluconic acid, lactic acid, malic acid, oxalic acid, and usnic acid. It’s often claimed that kombucha contains glucuronic acid, a chemical used by the liver for detoxification. However, chemical analysis of numerous samples of kombucha found no evidence of glucuronic acid. The same analysis found the amount of B vitamins present to be negligible.
Is it safe to make at home?
Generally, yes, if made with care. Kombucha is fairly acidic, with a pH of 2.5-4.5. (Cranberry juice has a pH of about 2.4.) The acidity discourages the growth of mold and other harmful microorganisms, but it’s still possible for dangerous microorganisms, like the fungus Aspergillus, to contaminate the kombucha. Brewers need to wash hands and equipment carefully to prevent contamination. Kombucha shouldn’t be brewed in ceramic, lead crystal, or painted containers, as the acid may leach lead and other heavy metals from them.
What studies have been done on kombucha?
To date, no clinical studies have been done using humans that back up kombucha’s purported benefits. That doesn’t mean the claimed benefits don’t exist: it simply means there are no studies to support them. Clinical studies using mice and rats have found kombucha increased energy, prolonged life, boosted immunity, and had potent antioxidant properties.
Can it really kill you?
It’s possible. In 1995, two women who drank kombucha derived from the same culture were hospitalized with severe lactic acidosis, a condition in which the body’s tissues and blood become overly acidic. One of the women died. In 2009, a 22-year-old man was hospitalized with the same condition. His doctor believed kombucha was the cause. Case studies have reported that kombucha very likely caused liver damage, serious allergic reactions, and cutaneous anthrax infections (due to skin application).
Pregnant women, children, the elderly, and anyone with a compromised immune system shouldn’t drink kombucha.
How about you?
What are your experiences—good, bad, or indifferent—with kombucha? Do you think the possible health benefits are worth the apparent risk?