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. I enjoyed making and drinking kombucha at home for a few months (for fun as much as anything, and grossing out my kids with the SCOBYs). But then my teeth became really sensitive. I wasn’t using secondary sweeteners and so I guessed it was the acidity of the final drink. Teeth have recovered since stopping the kombucha.

  2. I was hoping the article would be a bit more scientific as well.

  3. Hi Bruce,

    I have no idea about the first one, although research into other probiotic drinks/yoghurts has had conflicting results, some the bacteria has survived in small amounts and others it has not. This may have to do with how much acid a person produces and how quickly or not the product passes through.

    Most kombucha I have tasted has a slightly sweeter taste to non fermented tea as there is usually a small amount of sugars present. Also see comment re home made v bought.

    I doubt it would rot teeth unless you were consuming large amounts,

    I suspect home made tastes different to bought due to ingredients and time from manufacture to drinking. The type of tea used would be the main one, some bought don’t specify the type though. Aplify for example (passionfruit/lemonade) says they use Green, Oolong & Pu-erh teas. Many also have added sweeteners, erythritol (naturally fermented glucose) and stevia are both common. Some also have added probiotic Bacillus coagulans as well.

  4. I drink it because I love it! I bought it from a cafe once and now I make my own, which is fun and so much nicer. If its good for you as well,,, – great!

  5. >>But is that reaction true, or is it just a placebo effect?
    You appear not to have answered this question.

    I particularly would like to know:

    1. if the bacteria in kombucha can survive the acid in the stomach to reach the intestines;
    2. why you described it as “slightly fizzy and sweet” when it can/should have a Ph of 2.7 or so;
    3. does it rot your teeth, and
    4. why home made kombucha (like I make) tastes so different to the store-bought products.

    1. Hi Bruce, we’ve asked one of our researchers and this is what they said.

      1) Microbes can survive the stomach’s acidic environment. This has been demonstrated for specific microbial strains present in Yakult where the formulation of the product was optimised to aid this. However, for Kombucha, the ingredients/formulations and microbes vary considerably between different commercial products. Therefore it is very difficult to consistently conclude whether beneficial (or unwanted) microbes reach the large bowel unless this is rigorously tested for each Kombucha recipe.
      2) Many commercially available Kombucha products have sugar added which makes it sweet.
      3) Consumption of beverages that are higher in sugar and have a low pH, including kombucha, increase the risk of tooth decay.
      4) They agree with Rach’s response. Different ingredients equal different taste.

      Hope this helps.

      Kind regards,
      Team CSIRO

      1. So great to read all these comments. I want to know how I can get my home made booch probiotics tested . I make kombucha and kefir water then add them together to make “Boochir” . On average I use roughly 1/2 cup of sugar per 1Ltr of water in the first ferment, then on the second ferment add 1 tbsp of passionfruit pulp and 100ml of the last batch brewed to a regular 750ml bottle. Its extremely fizzy and no sweetness left by day 4. I’d like to think it has a large probiotics colony as my food sensitivities ( fodmaps to nearly everything) have slowly gone away.

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