Kombucha was the most searched wellness trend of 2019. We're investigating the hype behind it with science. So is kombucha a fermented friend or foe?
Two vials of orange looking liquid with straws in the foreground. There are jars with the same orange liquid in the background with cloth over it.

Kombucha is often touted as a highly nutritional swap for soft drinks. Image: Malyka Alexa/Getty Images

Did you know kombucha was the most searched for wellness trend in 2019? From DIY videos to the iconic meme, it’s no secret we all love kombucha.

Kombucha is a fermented tea drink. It’s slightly fizzy and sweet and it’s made by fermenting (breaking down) the sugars in sweetened black or green tea with a SCOBY (symbiotic colony of bacteria and yeast). It’s touted for its supposed gut health benefits as it has living microorganisms which act as a probiotic.

The ease of implementing kombucha into our lifestyles makes being healthy so easy. You get it, drink it, you’ve cleansed your gut and you feel amazing. But is that reaction true, or is it just a placebo effect?

Love your guts

The gut is amazing. Anatomically, it’s sectioned into five main parts: mouth, oesophagus, stomach, and small and large intestines. But it’s a little more complex than just a long 9-metre tube from mouth to bum. There are also secondary organs within our gastrointestinal tract – such as the liver, gallbladder and pancreas – which support digestion.

The main job of the gut is to extract essential nutrients from the food we eat and deliver them to all the cells in our body via the bloodstream. There is also increasing evidence our gut health is linked to our brain health. So, that’s why it makes sense we eat well to give our gut, and the rest of our body, the best outcome possible.

We all have a unique combination of gut bacteria known as the gut microbiome, hitting the hundreds in their varieties. Our gut bacteria establish in the first few years of life, and strongly influenced by how we’re delivered and whether we’re breastfed or not. But it does change as we age, stabilising around the time of our third birthday. It’s determined by diet, environment, genes and even our lifestyles. But sudden adverse changes in our gut microbiome can occur from disease, infection, antibiotics or other influences.

Gut health
Gut health helps weight loss

We all have our own unique combination of gut bacteria known as the gut microbiome.

Gut feeling

We’re told we should consume prebiotics and probiotics to ensure proper gut function and maintenance of a healthy gut microbiome. But what are pre- and probiotics? Probiotics are foods or drinks such as kombucha that contain live bacteria and provide a health benefit.

Researchers are investigating the effectiveness of probiotics. Some studies show the benefits of using probiotics like boosting immune health and reducing gastrointestinal disorders. But there are others which don’t replicate those same benefits. Probiotics are also extremely variable in their effectiveness. This depends on the strain you consume and whether it’s compatible with your own individual microbiota. It also depends on what food you eat it in, if there are enough microbes present or whether you have enough.

On the other hand, prebiotics are dietary fibres that pass undigested through the upper part of the gastrointestinal tract. They provide food for the ‘good’ bacteria in the large intestine. Think wholegrain bread and cereals, apples with the skin on, bananas and vegetables such as broccoli, eggplant and peas.

Bring the booch?

So how does this relate to kombucha? There’s limited and contradictory research into the gut benefits of kombucha. On top of that, there are no studies on humans which test the benefits of kombucha – they’re all lab and animal-based studies.

Let’s be clear. We’re not telling you to stop drinking kombucha. But when it comes to its benefits, it’s hit and miss. There are so many environmental factors which can cause their probiotics to not work. For example, store-bought kombucha can get hot in transit from factory to shop. This may kill the beneficial bacteria before it even gets to your mouth. Plus, the strains of good bacteria may not be compatible with your body.

If it does work for you, then great! The SCOBY may have created good bacteria that aligns with your gut microbiome. However, for a probiotic to have long-term benefits, you’d have to take it continuously. Some kombuchas are high in sugar as they have fruit juice added to aid the fermentation process and make them taste good. So, it would be best to look at your kombucha’s nutrition label before you go guzzling longnecks.

An array of cut up fruit and vegetables.

Your gut is able to achieve the same benefits as drinking kombucha. All you have to do is up your fibre from plant-based foods.

Gut health beyond the craze

If you want to achieve optimal gut health, fibre is your friend. Eating fibre provides food for the bacteria in your gut that produce a range of beneficial products including short-chain fatty acids. In doing so, they create an environment that can enhance immune response and inhibit gut inflammation. They can also reduce the growth of pathogenic bacteria such as E coli and other harmful microbes.

The best approach is to eat a wide range of plant-based foods. Focus on having a variety of coloured fruits and vegetables and a range of wholegrain breads and cereals every day. To further enhance gut health you can also include foods that contain resistant starch such as legumes, cold cooked starchy foods, green peas and firm bananas. Resistant starch promotes gut wall integrity, healthy digestion and optimal immune function.

So, if you want to improve your gut health, don’t fall for clever marketing campaigns. Instead, follow an approach supported by scientific evidence and feed your gut bacteria with a variety of plant-based foods.


  1. Very interesting article and great to learn about the benefits of fibre. I find unprocessed wheat fibre really good but not many places to buy it unfortunately. What can you say about Kefir? Does it have any probiotic benefits?

    1. Hi Rus – thanks for your question.

      Wheat fibre or wheat bran is a good source of dietary fibre that helps people stay regular. The evidence for the gut health benefits of Kefir is similar to that for Kombucha. There is limited clinical evidence showing that measures of gut health are improved when these food products that contain microbes are consumed. Based on current clinical evidence the best approach for improving the activity of the good/beneficial microbes in your gut is to focus on consuming plant based foods that are minimally processed; vegetables, fruits and wholegrain cereal foods.

      Kind regards,
      Team CSIRO

  2. I made Kombucha for a long time and know my teeth became very stained very quickly. When I stopped using the Kombucha my teeth staining stopped

  3. This is always an interesting topic. I’m hoping Grant could provide a little more information. Sorry to hear that you had to have major abdominal surgery. It sounds that the weeks after the surgery could well be worse than the surgery itself, which is endurable if you know you are on the mend. It sounds like you are well in tune with your body. Can you elaborate – did the re-establishment of your gut biome did this help with your incontinence?

  4. The Food Safety Information Council have a fact sheet on Kombucha. Some people may have dangerous side-effects from drinking too much. Check out the fact sheet on http://www.foodsafety.asn.au

  5. After major abdominal surgery, I had lost virtually all of my gut biome and was rendered incontinent. Initially I was given a probiotic yogurt with each meal however I continued to pass or vomit green bile liquids and was placed on ‘Nil by Mouth’ for a week or so, with a nasal drain. It took the best part of 2 years to feel that my gut was working well again and a gulp or two of Kombucha daily seemed to help. A mouthful of a kombucha would contain billions of bacteria, so drinking a whole bottle in one session seems pointless for this purpose. As I recovered I could feel the positive effect of my usual high fibre diet. These days, I occasionally add a probiotic or two, because my system behaves in comfortable balance. Kombucha and apple cider vinegar splashed on a salad, for example.

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