Kombucha has a golden reputation in the beverage world. It’s everywhere: from supermarket shelves to workplace refrigerators and even on tap in cafés.
As this fizzy fermented tea rose in popularity, so did claims of its health benefits, from improved digestion, metabolism, immunity, liver function, heart health and more.
To make kombucha, sweetened green or black tea is fermented with a symbiotic colony of bacteria and yeast, otherwise known as a SCOBY.
During the fermentation process, the yeast in the SCOBY breaks down the sugar in the tea and releases probiotic bacteria.
Kombucha becomes carbonated after fermentation, which is why the drink is fizzy.
What is kombucha?
Kombucha is a fermented tea drink made from green or black tea (or both), sugar, yeast and bacteria, and is believed to have originated in China about 2,000 years ago. It’s made by adding a colony of live bacteria and yeast, known as a SCOBY (symbiotic colony of bacteria and yeast), to sweetened tea and leaving it to ferment for a few weeks until it turns into a slightly sweet, slightly tart beverage that’s separated from the SCOBY and bottled.
There are a range of potential health benefits of kombucha, including:
1. Gut health
As this 2014 study confirms, the fermentation process of kombucha means that the drink is rich in probiotics. Probiotic bacteria are similar to healthful bacteria that are found in the gut.
More research is needed into how kombucha improves gut health, but the link between probiotics and gut health suggests it may support the digestive system.
The link between healthy bacteria in the digestive system and immune function is becoming clearer as more studies focus on gut health. If the probiotics in kombucha improve gut health, they may also strengthen the immune system.
2. Cancer risk
There is growing evidence to suggest drinking kombucha could help reduce the risk of cancer.
A 2008 study found that kombucha helped prevent the growth of cancer cells. Further research in 2013 found that kombucha decreased the survival of cancer cells. Both studies suggest kombucha could play a role in treating or preventing cancer.
It is important to note that these studies looked at the effects of kombucha on cancer cells in a test tube. More research is needed to see if people who drink kombucha have a reduced risk of developing cancer.
3. Infection risk
A type of acid called acetic acid, also found in vinegar, is produced when kombucha is fermented.
A study carried out in 2000 found that kombucha was able to kill microbes and help fight a range of bacteria. This suggests that it may help prevent infections by killing the bacteria that cause them before they are absorbed by the body.
4. Mental health
There may be a link between probiotics and depression, suggesting that drinking probiotic-rich kombucha could help promote positive mental health.
There are strong links between depression and inflammation, so the anti-inflammatory effect of kombucha may help alleviate some of the symptoms of depression.
A 2017 review looked at a number of existing studies and concluded that there is strong evidence that probiotics may help treat depression. However, further research is needed to prove how effective they are.
5. Heart disease
Levels of certain types of cholesterol increase the risk of heart disease. Studies in 2012 and 2015 found that kombucha helps to reduce levels of the cholesterol linked to heart disease. Cholesterol levels and heart disease are also influenced by diet, exercise, weight, lifestyle habits, and inflammation. However, the research cited here suggests drinking kombucha may help reduce the risk of heart disease.
At the same time, it is important to note that these studies were in rats. More research is needed to prove that kombucha reduces the risk of heart disease in humans.
6. Weight loss
When kombucha is made with green tea, it may aid weight loss. A 2008 study found that obese people who took green tea extract burned more calories and lost more weight than those who did not.
If kombucha is made with green tea, it follows that it could have a similarly positive effect on weight loss.
Again, researchers need to look at kombucha and weight loss specifically before this is certain.
7. Liver health
Kombucha contains antioxidants that help fight molecules in the body that can damage cells.
Some studies, the most recent being in 2011, have found that the antioxidant-rich kombucha reduces toxins in the liver. This suggests that kombucha may play an important role in promoting liver health and reducing liver inflammation.
However, studies to date have looked at rats and more research is needed to say with certainty how kombucha can support liver health in humans.
8. Type 2 diabetes management
Kombucha may also be helpful in managing type 2 diabetes.
A 2012 study found that kombucha helped to manage blood sugar levels in rats with diabetes. This finding suggests it may be helpful in type 2 diabetes management.
Again, more research is needed to say with certainty whether kombucha can have the same benefits in type 2 diabetes management for humans.
It is important to be careful when making kombucha at home, as it can ferment for too long. It is also possible for kombucha to become contaminated when not made in a sterile environment.
Over-fermentation or contamination may cause health problems, so it may be safer to buy kombucha in a store than to make it at home.
Store-bought kombucha normally has a lower alcohol content than homemade versions, but it is important to check the sugar content.
There are many potential health benefits of kombucha. However, it is important to remember that research is ongoing and not all benefits have been proven in studies with human participants.
If made properly or bought in-store, kombucha is a probiotic-rich drink that is safe to enjoy as part of a healthful diet.