Updated 15th June 2022

Is kombucha good for you?

Kombucha is a fermented and slightly carbonated sweet tea. Believed to have originated in China thousands of years ago, this distinctly tart drink has soared in popularity, thanks to its supposed health benefits.

But is there any truth to the claims? Keep reading to dive into the evidence and decide if drinking kombucha is right for you.

Websites and advertisements make a variety of kombucha-based health claims, such as warding off cancer, boosting the immune system, and lowering blood pressure and cholesterol. Unfortunately, there is very little evidence from human studies to support this.

Kombucha is a probiotic, so it may help improve the health of your gut. However, there is not enough evidence to prove this either.

At ZOE, we run the world’s largest ongoing scientific study of nutrition, with over 20,000 participants so far. We understand how important your gut microbiome is for good health.

If you’d like to learn about the specific bugs that live in your gut, start by taking our free quiz.

Are there any proven health benefits?

There are many health claims out there about drinking kombucha, such as protecting against inflammation, lowering cholesterol and blood pressure, slowing cancer growth, and boosting the immune system.

But is any of it actually true? Let’s dive into the evidence.

Overall, there is very little evidence in humans supporting the health benefits of kombucha. Many of the widely spread health claims stem from studies involving rats, dogs, cows, and other animals. 

While these animal studies can give important scientific clues, it’s important to remember that their findings don’t automatically translate to humans. We need human-specific research before any health claims can be made.

In one review of 15 different animal studies, evidence suggests that drinking kombucha may help slow inflammation, improve liver function, and promote a healthy gut.

Researchers also concluded that kombucha might be helpful for controlling and treating obesity and obesity-related illnesses, although further research is needed.

Many people also believe that kombucha can help ease symptoms of intestinal diseases, such as irritable bowel syndrome (IBS). However, the evidence is not clear for this.

Potential probiotic benefits

Kombucha is a probiotic, which means it has living microorganisms in it. Once consumed, these microorganisms may take up residence in your gut and can benefit your health. 

In a review of more than 30 studies, researchers found that probiotics — such as the ones found in kombucha — might help improve symptoms of IBS. However, the quality of evidence was very low, and they made no further recommendations.

Some scientists suggest that adding kombucha to skincare and cosmetic products could be beneficial.

In one study, researchers found that kombucha ferments were associated with anti-aging and anti-inflammatory benefits, as well as promoting a healthy skin microbiome, which are the millions of microorganisms that live on your skin and play an important part in keeping you healthy. 

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Other potential health benefits

Animal studies have suggested other possible health benefits of kombucha, such as:

As mentioned, while these animal studies are important, there is very little human evidence, and it is unknown whether the results will be the same in humans.

There is some evidence to suggest that kombucha might help manage blood sugar. However, there are many different varieties of kombucha available, and some products with a higher sugar content may actually lead to spikes in blood sugar.

Although rises in blood sugar are normal after a meal, large spikes in blood sugar can cause health issues in the long run.

ZOE runs the largest nutrition science study in the world, and our research shows that everyone responds differently to foods. Even identical twins can have different blood sugar and blood fat responses to the same food.

If you’d like to learn more about how your body responds to food, start by taking our free quiz.

What’s in kombucha?

Kombucha is made from a handful of main ingredients, including black or green tea leaves, water, sugar, and something called a SCOBY, which is a disc-shaped symbiotic culture of bacteria and yeast.

Ingredients such as lavender, ginger, blueberry, or hibiscus can be added to the kombucha for a variety of flavors.

The first step of making kombucha is steeping tea in boiling water and then adding sugar. After the sweetened tea cools, the SCOBY is added.

The yeast in the SCOBY reacts with the sugar in the tea, fermenting the mixture. It will then ferment at room temperature for 7–10 days, or until it reaches the desired flavor and chemical properties.

After adding any additional flavors to the mixture and bottling the kombucha, it continues to ferment for another couple of weeks. During this time, the bottle traps the carbon dioxide produced from the fermentation process, carbonating the drink. 

The kombucha is then refrigerated, and, when produced commercially, shipped off to retailers.

Potential risks

While scientists are still studying the health benefits of drinking kombucha, there are some potential risks to be aware of.

Kombucha contains small amounts of alcohol, as it’s a byproduct of the fermentation process. So, people with liver problems, sensitivity to alcohol, or those who are pregnant may want to talk to their healthcare provider before drinking it. 

Making kombucha carefully is important for it to be safe to drink. Commercially produced kombucha is regulated, and manufacturers must follow strict food safety guidelines, whereas incorrectly preparing homemade or small-batch kombucha can be dangerous

Preparing kombucha incorrectly lets potentially harmful bacteria and molds contaminate the drink, and it may make you sick.

Dangerous chemicals can also leach into the drink if the wrong container is used. If you choose to make it at home, make sure to follow the above food safety guidelines closely.

Even with proper food safety precautions, people have reported other health complications from drinking kombucha, including:

  • lactic acidosis, or having too much lactic acid in your blood

  • yellowing of the skin, known as jaundice

  • nausea

  • vomiting

  • digestive problems, such as bloating, excess gas, or diarrhea, especially for people with IBS

Can you drink kombucha every day?

There simply isn’t enough human research for us to know the dangers of drinking too much kombucha, especially given the reported health complications and how much each product varies.

A previous study published by the Centers for Disease Control and Prevention (CDC) in 1995 states that drinking up to 4 ounces of kombucha per day is probably safe for a healthy adult.

However, the risks are unknown for people with health complications or those who drink a lot of it. The CDC have not made any updated recommendations since.

Also consider that kombucha drinks vary in calories and sugar, and drinking kombucha every day could lead to excess calorie and sugar consumption. Those who are sensitive to caffeine should also be cautious of drinking it daily.

Additionally, there may be differences in the quality of store-bought and home-brewed kombucha. As mentioned above, commercially brewed kombucha is subject to a strict set of guidelines to ensure food safety. 

Homemade brewing may not follow the same precautions and could potentially make you sick if not done correctly.

Summary

Kombucha is a fermented sweet tea made of tea, water, sugar, and a SCOBY. 

Many sources make health claims about drinking kombucha, and some animal studies have seen potential benefits. However, human studies are very limited, and results from animal studies don’t automatically translate to humans. 

There are potential risks of drinking kombucha, especially for people with other health conditions or those who are pregnant.

With the lack of long-term human studies, the dangers of drinking too much kombucha are unknown, but some people have reported complications.

Although the evidence that kombucha improves gut health is also lacking, there’s no doubt that gut bacteria are important for good health. As part of ZOE’s research, we’ve analyzed thousands of gut microbiomes.

We’ve identified 15 “good” bacteria that are associated with better health and 15 “bad” bacteria that are linked to poor health measures. If you’d like to learn more about the bacteria in your gut microbiome, start by taking our free quiz today.

We know that everyone responds to foods differently. Once you’ve taken our at-home test, we can give you personalized nutrition advice tailored to your body’s specific needs.

Sources

A mini review on antidiabetic properties of fermented foods. Nutrients. (2018). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6316541/

American College of Gastroenterology monograph on the management of irritable bowel syndrome and chronic idiopathic constipation. The American Journal of Gastroenterology. (2014). https://journals.lww.com/ajg/Fulltext/2014/08001/American_College_of_Gastroenterology_Monograph_on.2.aspx

Effect of fermentation time on the content of bioactive compounds with cosmetic and dermatological properties in kombucha yerba mate extract. Scientific Reports. (2021). https://www.nature.com/articles/s41598-021-98191-6

Effect of kombucha intake on the gut microbiota and obesity-related comorbidities: a systematic review. Critical Reviews in Food Science and Nutrition. (2021). https://pubmed.ncbi.nlm.nih.gov/34698580/

Hypoglycemic and antilipidemic properties of kombucha tea in alloxan-induced diabetic rats. BMC Complementary and Alternative Medicine. (2012). https://pubmed.ncbi.nlm.nih.gov/22591682/

Kombucha. (2019). https://www.ttb.gov/kombucha

Kombucha: a systematic review of the empirical evidence of human health benefit. Annals of Epidemiology. (2019). https://www.sciencedirect.com/science/article/pii/S1047279718307385#bib18

Kombucha brewing under the Food and Drug Administration model Food Code: risk analysis and processing guidance. Journal of Environmental Health. (2013). https://agriculture.ny.gov/system/files/documents/2019/03/kombuchanummer.pdf

Kombucha: is a cup of tea good for you? BMJ Case Reports. (2017). https://casereports.bmj.com/content/2017/bcr-2017-221702.abstract

Safety aspects and guidance for consumers on the safe preparation, handling, and storage of kombucha — a fermented tea beverage. Food Protection Trends. (2018). https://www.foodprotection.org/files/food-protection-trends/sep-oct-18-murphy.pdf

Sequence-based analysis of the bacterial and fungal compositions of multiple kombucha (tea fungus) samples. Food Microbiology. (2014). https://pubmed.ncbi.nlm.nih.gov/24290641/

The human skin microbiome. Nature Reviews Microbiology. (2018). https://www.nature.com/articles/nrmicro.2017.157

Traditional low-alcoholic and non-alcoholic fermented beverages consumed in European countries: a neglected food group. Nutrition Research Reviews. (2017). https://www.cambridge.org/core/journals/nutrition-research-reviews/article/traditional-lowalcoholic-and-nonalcoholic-fermented-beverages-consumed-in-european-countries-a-neglected-food-group/F7DBC2D563B72D393E1EC47F4B228877

Unexplained severe illness possibly associated with consumption of kombucha tea. Morbidity and Mortality Weekly Report. (1995). https://www.cdc.gov/mmwr/preview/mmwrhtml/00039742.htm

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