Drinking kombucha is said to improve digestion through probiotics and boost immunity through antioxidants, all from an added symbiotic colony of bacteria and yeast (SCOBY).
Kombucha is a type of beverage made from fermented green or black tea. It is slightly fizzy and has a mild sour or vinegar-like taste. Marketed for several health benefits, most of kombucha tea’s nutritional value is not backed by any substantial scientific or medical evidence. Moreover, there are several reports about the harmful effects of the beverage. Thus, you must ask your healthcare provider before trying kombucha for any of the claimed health benefits.
There have been several, rather overenthusiastic, claims about the benefits of drinking kombucha, including:
- Managing cancer
- Treating liver diseases
- Boosting immunity through antioxidants
- Treating arthritis
- Treating and preventing cardiovascular diseases
- Managing diabetes
- Reducing weight through probiotics
- Fighting infections
- Healing wounds
- Treating gastric ulcers and other digestive issues
- Boosting skin health
- Promoting healthy hair
- Managing premenstrual syndrome (PMS)
- Preventing memory loss
None of the above benefits have enough clinical trials to support them. Hence, you must exercise adequate caution in trying the beverage or any other herbal preparation for medicinal use. There is also a risk of untoward drug–kombucha interactions, so consider your doctor’s advice.
What are the ingredients and fermentation process of kombucha?
Kombucha tea is made by fermenting black or green tea in the presence of various types of yeast and bacteria. The yeast and bacteria together form a pellicle or symbiotic culture of bacteria and yeast (SCOBY). Kombucha tea is commercially available and can be made at home easily by using a do-it-yourself (DIY) kombucha-making kit. It is generally made in glass jars covered with tight-weave fabric or paper coffee filters. Tea leaves, black or green, are first steeped in hot water along with some sugar.
Tea leaves are then removed, and the sweetened mixture is allowed to cool. After it gets cooled, some vinegar or leftover kombucha is added. This helps make the mixture acidic. Finally, a SCOBY is added. To begin the kombucha fermentation process, the brew is covered with a tight weave cloth or paper coffee filter and is left to ferment at room temperature for about 7 to 30 days.
The growing fungal spores float on the surface of the fermented tea. The fungal mycelium (a thread-like structure) keeps doubling in mass every week. A portion of these mycelia may be used for making more kombucha tea.
Although sugar is added while making kombucha tea, its content progressively decreases, whereas the acidity of the beverage increases. The yeast uses the sugar to form ethanol, whereas the bacteria use the ethanol produced to make acetic acid. The acetic acid further increases ethanol production using the yeast. Thus, the bacteria and yeast help each other to grow (symbiosis). The resultant ethanol and acetic acid prevent the growth of other microorganisms.
Several other products are also formed during the kombucha fermentation process, along with gases that make the tea fizzy. These products include mild acids, carbon dioxide, sucrose, fructose, phenolic compounds, minerals and some vitamins such as C and B.
Like other fermented foods, kombucha contains some alcohol as a by-product of the tea fermentation process, however, this alcohol content is generally very low, especially for most traditional kombucha recipes. Furthermore, the beverage does contain beneficial ingredients, such as probiotics and antioxidants.
Are there any side effects of kombucha?
Drinking kombucha tea can cause various side effects, such as:
- Liver damage
- Abdominal cramps
- Acidosis (a condition in which the pH of the blood becomes low or acidic)
- Lead poisoning (when brewed in containers that have lead, such as clay pots)
- Food poisoning
- Severe bacterial and fungal infections particularly in people with compromised immunity, such as human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS)
Kombucha is also possibly unsafe for pregnant and breastfeeding women. It should particularly be avoided in people with compromised immunity, those who have a drinking problem, those with diabetes, those undergoing surgery and those with diarrhea or irritable bowel syndrome (IBS).
According to a report by the Centers for Disease Control and Prevention (CDC) in 1995, drinking kombucha was linked to two cases of severe metabolic acidosis, resulting in the death of one of the affected people. Since then, there have been several reports of serious side effects of consuming kombucha. If at all you wish to try it, do take your doctor’s advice.