They hype around kombucha has built a lot in the last few years. It’s now in every supermarket, health food shop, and probably was the alcohol free option at the last party you went to. But with anything that gets popular quickly, it’s always worth asking: does it actually do anything, or is it just fizzy tea with good branding?
We are all sick of reading AI slop, you won't find any of that here, below are fully researched referenced facts with data to back them up.
What’s in kombucha that could affect your Gut?
Kombucha is made by fermenting sweetened tea with a SCOBY, which stands for Symbiotic Culture of Bacteria and Yeast (try saying that in a hurry). During fermentation, the culture produces: organic acids (mainly acetic and lactic acid), natural carbonation (from CO2), B vitamins, live bacteria and yeast and trace amounts of alcohol (under 0.5% usually, but that depends how you brew it).
The live cultures are the bit people talk about most when it comes to gut health. Kombucha contains naturally occurring bacteria and yeast that form during fermentation. A study published in 2022 found that kombucha contains over 200 microbial species, including lactic acid bacteria, which are the same family found in yoghurt and kefir, which are also frequently celebrated for their gut supporting qualities (Tran T et al, 2022).
So what does the research actually say?
A controlled clinical trial followed participants over eight weeks, comparing those who drank kombucha against a control group. The researchers found that kombucha consumption was associated with an increase in Weizmannia, a probiotic strain that’s naturally occurs in kombucha, within the gut microbiome of participants. They also observed changes in their blood fat levels and biochemical markers (health indicators) (Cerdo T et al, 2024)
It’s a promising study. It’s also a fairly small one. The researchers themselves noted that larger trials are needed to draw firm conclusions.
A separate systematic review published in Fermentation (MDPI, 2025) looked across multiple kombucha trials focused on microbiota and metabolic health. The review found consistent evidence that kombucha positively influences gut micro composition, though effects varied depending on fermentation quality, dosage, and individual gut profiles. This is one of the key reasons why you cannot just pick up any old kombucha from the supermarket. The brewing method and how the kombucha is processed afterwards have an impact of the quality of the kombucha you receive.
The takeaway? Kombucha shows real promise, particularly for supporting microbial diversity in the gut. It’s not a cure for anything. But as part of a diet that already includes varied, wholefoods, it’s a genuinely useful addition.
Why Microbial Diversity Matters
Your gut is home to trillions of microorganisms. Scientists call this collection the gut microbiome, and it plays a role in digestion, immune function, inflammation, and even mood. Research increasingly shows that diversity within the microbiome matters: a wider variety of microbial species is generally associated with better health outcomes.4
Fermented foods like kombucha, kefir, kimchi, and natural yoghurt are among the few dietary sources that can actively introduce new live organisms into the gut. Whether they survive the digestive process and colonise long-term is still an area of active research, but short-term impacts on microbial composition have been observed in multiple studies.
What to Look for in a Good Kombucha
Quality matters enormously here. A lot of commercial kombucha is filtered down to such a refined level after brewing, which filters out almost all of the positive bacteria. If gut health is the goal, you want raw, unpasteurised kombucha that’s been properly fermented.
Look for:
- Raw and unfiltered on the label
- A short, recognisable ingredients list
- Low sugar per serving (roughly 5g or under per 100ml)
- A natural sediment or slight cloudiness (that’s the live culture)
At Future Ferments, our kombucha is carefully brewed in small batches, unfiltered, and made with real ingredients. No shortcuts.
The Bottom Line
Kombucha is not magic. It won’t fix a bad diet or cure a chronic condition. But the science does support it as a fermented drink that can contribute to a more diverse gut microbiome, especially when it’s raw, low in sugar, and properly made.
If you want more background on what kombucha actually is and how it’s made, our Kombucha 101 post covers the basics.
References
- Tran T, et al. Microbial Diversity and Characteristics of Kombucha as Revealed by Metagenomic and Physicochemical Analysis. Nutrients, 2022. PMC8704692
- Cerdo T, et al. Modulating the human gut microbiome and health markers through kombucha consumption: a controlled clinical study. Scientific Reports, 2024. Nature | PubMed
- Benefits of Kombucha Consumption: A Systematic Review of Clinical Trials Focused on Microbiota and Metabolic Health. Fermentation, MDPI, 2025. MDPI
- Valdes AM, et al. Role of the gut microbiota in nutrition and health. BMJ, 2018. BMJ