Kombucha: What It Is, What We Know About Its Benefits and How to Drink It Safely

Kombucha is a drink made from sweetened tea that has been fermented with a culture of bacteria and yeasts, commonly called a SCOBY. The result is a lightly fizzy drink with a tangy taste and an aroma reminiscent of apple cider vinegar. It has become very popular in recent years, and with that popularity came plenty of exaggerated promises. It is worth separating what is reasonable from what is marketing.

How it is made

Tea is brewed (usually green or black), sugar is added, and the SCOBY goes in together with some kombucha from a previous batch. Over one to two weeks, the yeasts turn sugar into alcohol and carbon dioxide, and the bacteria convert part of that alcohol into organic acids such as acetic acid. That is why the drink turns sour and develops a slight sparkle.

What may be interesting about it

• Live microorganisms: unpasteurised kombucha contains living bacteria and yeasts. However, the species vary a lot from batch to batch, so it is not accurate to assume it works as a probiotic with a proven effect.
• Tea compounds: the base tea provides polyphenols, which are also found in plain tea. Part of that profile remains after fermentation.
• A swap for very sugary drinks: if you replace soft drinks with a low-sugar kombucha, your day may improve simply because you consume less added sugar.

What science has not yet confirmed

Many articles mention liver detox, stronger immunity or weight loss. So far, most studies have been done in laboratories or on animals, and trials in people are few and small. There is therefore no basis to claim that kombucha cures or prevents disease, or "cleanses" the body. Your liver and kidneys already do that job, and no drink replaces them.

The idea that it improves digestion should also be treated with caution. Some people feel fine with it, while others notice discomfort, gas or heartburn. The response is individual.

Important precautions

1. Sugar: many commercial brands contain meaningful amounts of sugar. Read the label and favour lower-sugar versions.
2. Residual alcohol: fermentation produces small amounts of alcohol. Even when a drink is sold as non-alcoholic, traces may remain, which matters to anyone who avoids alcohol for any reason.
3. Acidity: being acidic, it can irritate a sensitive stomach and, with frequent consumption, affect tooth enamel. Drinking in moderation and rinsing your mouth with water afterwards helps.
4. Caffeine: because it is made with tea, it contains some caffeine, generally less than a cup of coffee.
5. Home brewing: without strict hygiene, contamination by mould or unwanted bacteria can occur. Use well-washed glass containers, never glazed ceramic or reactive metal, and discard the batch if you see mould, which looks fuzzy and coloured.

Who should be more careful

Pregnant or breastfeeding women, young children, people with a weakened immune system and those with chronic conditions should talk to their doctor before adding it to their diet. The same applies if you take regular medication or have diabetes, because of the sugar content.

How to get started

If you want to try it, start with a small amount, around 100 to 150 ml once a day, and observe how your body reacts. You can drink it chilled, with meals or between them, and add flavour with lemon slices, ginger or fresh fruit.

In short

Kombucha can be a pleasant drink and an alternative to sugary beverages, but it is not a remedy or a shortcut to health. What really matters is still the whole picture: a varied, fibre-rich diet, good hydration, exercise and enough sleep. If you have questions about your own situation, your doctor or a dietitian is your best ally.