--- title: "Fermented Foods and Gut Health: What the Evidence Says" description: Are fermented foods good for your gut? What the research shows for yoghurt, kefir, kimchi and sauerkraut, how to choose them, and who should take care. --- [![HealthBank](https://blog.healthbank.io/hs-fs/hubfs/HB_Logo.png?width=100&height=91&name=HB_Logo.png)HealthBank/Blog](https://blog.healthbank.io) [Blog](https://blog.healthbank.io) [Write for us](https://blog.healthbank.io/write-with-healthbank?utm_source=blog&utm_campaign=contributor&utm_medium=nav) [Help centre](https://help.healthbank.io) [Contact](https://help.healthbank.io/how-can-i-contact-you) [Back to HealthBank](https://dashboard.healthbank.io/app/dashboard) [Blog](https://blog.healthbank.io)  ›  Gut health # Are Fermented Foods Good for Your Gut? What the Evidence Says [![Robbie Clark](https://blog.healthbank.io/hs-fs/hubfs/Blog/Authors/robbie-clark-avatar.png?width=32&height=32&name=robbie-clark-avatar.png)Robbie Clark](https://www.healthbank.io/p/robbie-clark) 27 Oct 2026 Written by [Robbie Clark](https://www.healthbank.io/p/robbie-clark), BExSc (Nutrition), M (Nutr+Diet), Accredited Practising Dietitian (APD) and Exercise Scientist · Last updated 16 October 2026 · [6 references](https://blog.healthbank.io/fermented-foods-and-gut-health-what-the-evidence-says#references) The short answer - Fermented foods such as yoghurt, kefir, sauerkraut and kimchi may support gut health, but the human evidence is still limited.[1](https://blog.healthbank.io/fermented-foods-and-gut-health-what-the-evidence-says#ref-1),[4](https://blog.healthbank.io/fermented-foods-and-gut-health-what-the-evidence-says#ref-4) - In trials with healthy adults, eating fermented foods led to small improvements in bloating, wind and constipation.[4](https://blog.healthbank.io/fermented-foods-and-gut-health-what-the-evidence-says#ref-4) - Not every fermented food contains live microbes. Bread, most beer and wine, and heat-treated, shelf-stable pickles don't.[2](https://blog.healthbank.io/fermented-foods-and-gut-health-what-the-evidence-says#ref-2) - If you're pregnant, skip kombucha, kefir and other fermented drinks, and anything made with unpasteurised milk.[6](https://blog.healthbank.io/fermented-foods-and-gut-health-what-the-evidence-says#ref-6) Kimchi, kefir and kombucha have gone from health-food shops to supermarket shelves, usually with a gut health promise attached. As a dietitian, I think fermented foods are a tasty addition to a healthy diet. But the evidence is more modest than the marketing, and a few people need to be careful. Here's what the research actually shows. ## What are fermented foods? Fermented foods are made when microbes, such as bacteria or yeasts, grow in a food and change it.[2](https://blog.healthbank.io/fermented-foods-and-gut-health-what-the-evidence-says#ref-2) That's how milk becomes yoghurt, cabbage becomes sauerkraut and soybeans become miso. Common examples include: - Yoghurt, kefir and some cheeses - Sauerkraut, kimchi and other naturally fermented vegetables - Miso, tempeh and natto - Kombucha - Sourdough bread Whether a food still contains live microbes depends on how it's made. Bread is baked after fermentation, most beer and wine are filtered or treated, and shelf-stable sauerkraut and pickles are usually heat-treated. All of these are fermented, but the microbes in them are no longer alive.[2](https://blog.healthbank.io/fermented-foods-and-gut-health-what-the-evidence-says#ref-2) ## Are fermented foods the same as probiotics? No. A probiotic is a specific, identified strain of live microbe that has been shown in research to have a health benefit. Most fermented foods contain a mix of microbes that haven't been tested this way, so they shouldn't be called probiotics.[2](https://blog.healthbank.io/fermented-foods-and-gut-health-what-the-evidence-says#ref-2) That doesn't make them less worthwhile. It just means a jar of sauerkraut can't promise the same effect as a probiotic studied for a particular condition. Get support from a practitioner who treats gastrointestinal conditions Find practitioners on HealthBank who work with IBS and other gut conditions. Many offer a free discovery call, online, by phone or in person. [Find a gut health practitioner →](https://www.healthbank.io/practitioners?specialties%5B%5D=Digestive+Support&specialties%5B%5D=Irritable+Bowel+Syndrome&specialties%5B%5D=Functional+Gut+Issues) ## Are fermented foods good for gut health? They may be, but there's less human research than you might expect. Only a handful of fermented foods, including kefir, sauerkraut, natto and sourdough bread, have been tested in clinical trials for gut effects. Kefir has been studied the most. Popular foods such as kimchi, miso, tempeh and kombucha haven't yet been tested in human trials for gut health.[1](https://blog.healthbank.io/fermented-foods-and-gut-health-what-the-evidence-says#ref-1) A 2025 review pooled trials in healthy adults. People who ate fermented foods had slightly more regular bowel movements, less constipation, and less bloating and wind. They didn't have less abdominal pain. The researchers rated most of the evidence as low certainty, so the results are promising rather than proven.[4](https://blog.healthbank.io/fermented-foods-and-gut-health-what-the-evidence-says#ref-4) Fermented foods may also make your gut bacteria more varied. In a small 10-week study of 36 healthy adults, people who built up to about six servings of fermented foods a day had a more diverse mix of gut bacteria and lower levels of several inflammation markers in their blood.[3](https://blog.healthbank.io/fermented-foods-and-gut-health-what-the-evidence-says#ref-3) It's an interesting result, but it's one small study. ## Can fermented foods help with weight, mood or immunity? Researchers are studying how gut bacteria relate to weight, mood and immunity, and you'll often see fermented foods promoted for all three. So far, most of this research has been done in animals or with specific probiotic supplements rather than everyday foods, so it's too early to say that fermented foods help with these. ## How can you add fermented foods to your diet? Start small and build up over a couple of weeks. Some people notice more wind or bloating at first. Easy ways to include them: - Have plain yoghurt or kefir with breakfast, or use it in smoothies and dressings - Add a spoonful of sauerkraut or kimchi to sandwiches, salads, eggs or rice bowls - Use miso in soups, marinades and dressings - Try tempeh in stir-fries Fermented foods work best as part of an overall healthy diet with plenty of fibre-rich plant foods. Sauerkraut, kimchi and miso can be high in salt, so keep portions small if you're watching your salt intake. If you have IBS, some fermented foods may trigger symptoms, so check with your practitioner. ## How do you choose fermented foods at the supermarket? - **Look for "live cultures" on the label.** Wording such as "contains live and active cultures" tells you live microbes are present.[2](https://blog.healthbank.io/fermented-foods-and-gut-health-what-the-evidence-says#ref-2) - **Check where it's stored.** Live-culture products are usually in the fridge section. Shelf-stable versions have usually been heat-treated, so they don't contain live microbes.[2](https://blog.healthbank.io/fermented-foods-and-gut-health-what-the-evidence-says#ref-2) - **Check the sugar and salt.** Flavoured yoghurts, kefirs and kombuchas can be high in added sugar. - **Follow storage instructions and use-by dates.** ## Who should be careful with fermented foods? Most people can enjoy fermented foods safely. Pregnant women, older people and people with weakened immune systems are more at risk from foodborne illness such as Listeria, which can be serious.[5](https://blog.healthbank.io/fermented-foods-and-gut-health-what-the-evidence-says#ref-5) If that's you, avoid unpasteurised (raw) milk products and soft cheeses, and talk to your practitioner before trying fermented foods you haven't had before.[5](https://blog.healthbank.io/fermented-foods-and-gut-health-what-the-evidence-says#ref-5),[6](https://blog.healthbank.io/fermented-foods-and-gut-health-what-the-evidence-says#ref-6) Pregnant? Skip fermented drinks and unpasteurised dairy Don't drink kombucha, kefir, kvass or homemade ginger beer while pregnant, as they can be contaminated and may contain alcohol. Yoghurt made from pasteurised milk is fine.[6](https://blog.healthbank.io/fermented-foods-and-gut-health-what-the-evidence-says#ref-6) Get support from a practitioner who treats gastrointestinal conditions Find practitioners on HealthBank who work with IBS and other gut conditions. Many offer a free discovery call, online, by phone or in person. [Find a gut health practitioner →](https://www.healthbank.io/practitioners?specialties%5B%5D=Digestive+Support&specialties%5B%5D=Irritable+Bowel+Syndrome&specialties%5B%5D=Functional+Gut+Issues) ## Frequently asked questions ### Do all fermented foods contain probiotics? No. Many fermented foods contain live microbes, but they're only called probiotics when a specific strain has been shown to have a health benefit, and some fermented foods have no live microbes at all.[2](https://blog.healthbank.io/fermented-foods-and-gut-health-what-the-evidence-says#ref-2) ### Is sourdough bread good for gut health? Sourdough is fermented, but baking kills the microbes, so it doesn't add live bacteria to your gut.[2](https://blog.healthbank.io/fermented-foods-and-gut-health-what-the-evidence-says#ref-2) ### Is kombucha good for your gut? Kombucha hasn't been tested in human trials for gut health yet, and it isn't recommended during pregnancy.[1](https://blog.healthbank.io/fermented-foods-and-gut-health-what-the-evidence-says#ref-1),[6](https://blog.healthbank.io/fermented-foods-and-gut-health-what-the-evidence-says#ref-6) ### How much fermented food should I eat? There's no recommended amount. Start with a small serve a day and build up to what suits you. ### Can fermented foods cause bloating? Some people notice more wind or bloating when they first add fermented foods, so start small. Over time, trials suggest bloating may improve slightly.[4](https://blog.healthbank.io/fermented-foods-and-gut-health-what-the-evidence-says#ref-4) ## References **Research (PubMed)** 1. Dimidi E, Cox SR, Rossi M, Whelan K. Fermented foods: definitions and characteristics, impact on the gut microbiota and effects on gastrointestinal health and disease. *Nutrients.* 2019;11(8):1806. [PubMed 31387262](https://pubmed.ncbi.nlm.nih.gov/31387262/) 2. Marco ML, Sanders ME, Gänzle M, et al. The International Scientific Association for Probiotics and Prebiotics (ISAPP) consensus statement on fermented foods. *Nat Rev Gastroenterol Hepatol.* 2021;18:196–208. [DOI 10.1038/s41575-020-00390-5](https://doi.org/10.1038/s41575-020-00390-5) 3. Wastyk HC, Fragiadakis GK, Perelman D, et al. Gut-microbiota-targeted diets modulate human immune status. *Cell.* 2021;184(16):4137–4153.e14. [PubMed 34256014](https://pubmed.ncbi.nlm.nih.gov/34256014/) 4. Mukherjee A, Farsi DN, Garcia-Gutierrez E, et al. Impact of fermented foods consumption on gastrointestinal wellbeing in healthy adults: a systematic review and meta-analysis. *Front Nutr.* 2025;12. [DOI 10.3389/fnut.2025.1668889](https://doi.org/10.3389/fnut.2025.1668889) **Australian guidelines** 1. Food Standards Australia New Zealand. Listeria in food. [View source](https://www.foodstandards.gov.au/consumer/prevention-of-foodborne-illness/bacteria-foodborne-illness/listeria) 2. NSW Food Authority. Foods to eat or avoid when pregnant. [View source](https://www.foodauthority.nsw.gov.au/consumer/life-events-and-food/pregnancy/foods-to-eat-or-avoid-when-pregnant) *This article is general information, not medical advice. Speak with your practitioner about your own situation before changing your diet.* [Gut health](https://blog.healthbank.io/tag/gut-health) [![Robbie Clark](https://blog.healthbank.io/hs-fs/hubfs/Blog/Authors/robbie-clark-avatar.png?width=72&height=72&name=robbie-clark-avatar.png)](https://www.healthbank.io/p/robbie-clark) Written by **[Robbie Clark](https://www.healthbank.io/p/robbie-clark)** Robbie is a Sydney-based Accredited Practising Dietitian (APD) and Exercise Scientist with over 17 years of experience. He holds a Bachelor of Exercise Science (Nutrition) and a Master of Nutrition and Dietetics, and is the Director and Co-founder of HealthBank. [Book a free 15-min call](https://dashboard.healthbank.io/booking/attendance-modes?practitionerId=7a900b23-04a3-4c3c-b14e-e3405c1af6d7&consultationTypeId=4e536270-c479-40a5-af89-691502f4578d) [View Robbie's profile →](https://www.healthbank.io/p/robbie-clark) ## Related articles ### [Gut health What Is the Low FODMAP Diet? A Beginner's Guide for IBS What is the low FODMAP diet? How it eases IBS symptoms, the 3 steps, how long to follow it, and which foods ... Read article →](https://blog.healthbank.io/low-fodmap-diet-a-beginners-guide-for-ibs) ### [Gut health What Are Prebiotics? Foods, Benefits and How They Differ From Probiotics What are prebiotics? How they feed your gut bacteria, how they differ from probiotics, the best prebiotic ... Read article →](https://blog.healthbank.io/what-are-prebiotics-and-where-do-you-find-them) ### [Gut health How Much Fibre Do You Need a Day? Why It Matters and How to Get More How much fibre do you need a day? Australian targets for adults and kids, why fibre matters, easy ways to eat ... Read article →](https://blog.healthbank.io/fibre-why-it-matters-and-how-to-get-more) ### Questions about using HealthBank? Find step-by-step guides, or chat with our support team. 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