Fermented foods have gone from zero to hero, with our growing interest spurred by social media posts touting their many health benefits, from improved digestion and gut health to a more resilient immune function and a reduced risk of conditions like type 2 diabetes and heart disease.
Fermented foods are nothing new. They’ve been around for centuries, used originally as a means of preservation before refrigerators were commonplace; they also play a significant role in many food cultures. If you’ve shied away from fermented foods because the idea seems a bit weird, think again – many of the healthiest options are actually regular foods many of us eat every day.
What is fermentation?
During fermentation, micro-organisms like bacteria, yeast or fungi convert organic compounds like sugars and starch into alcohol, acids or gases. This metabolic process takes place without oxygen and is employed in the making of various foods and drinks, including alcoholic drinks like wine and beer, non-alcoholic drinks such as kombucha, and fermented foods like yogurt, sauerkraut, cheese and bread. Fermentation can be initiated by the micro-organisms naturally present in the food or environment (known as spontaneous fermentation), or by the addition of a starter culture. Kimchi and sauerkraut are produced by spontaneous fermentation, whereas a starter culture is used to produce kefir or natto, for example.
Discover our full range of health benefit guides and check out the health benefits of fermenting, what are probiotics and our favourite fermented food recipes.
What are the healthiest fermented foods?
1. Cheese (including aged cheddar, parmesan, gouda and mozzarella)
Would you believe that some cheeses are more effective than a probiotic supplement? When made traditionally, mozzarella is a classic example, although be aware that levels of beneficial bacteria will vary depending on the source of the milk used.
Discover the healthiest cheeses.
Be inspired by our recipes, including caprese salad, courgette, potato and cheddar soup and parmesan spring chicken.
2. Yogurt
Interestingly, consuming 100g of probiotic yogurt every day may be beneficial for helping manage stress and anxiety in postmenopausal women. We need to understand more about the mechanism behind this, so more studies are needed, but it may be a good habit to start.
Discover the health benefits of yogurt.
Use up yogurt to make our roast aubergines with yogurt and harissa, instant frozen berry yogurt and roasted beetroot with za’atar, chickpeas and harissa yogurt.
3. Buttermilk
Buttermilk is traditionally made from the liquid left after churning butter, but mnodern commercial versions are more likely to be made by adding lactic acid bacteria to milk. The bacteria thicken the liquid by curdling natural milk proteins (casein), which gives it a tart flavour. One of the benefits of lactic acid bacteria is that they can make lactose, the natural sugar in milk, easier to digest. Another benefit of consuming buttermilk is that it may be associated with reduced cholesterol levels in men and women.
Buttermilk is often used in baking and cooking, for example as a marinade for meat because it helps tenderise tougher cuts. Use it in these delicious recipes: green salad with buttermilk dressing, buffalo cauliflower wings, paprika buttermilk chicken courgette skewers and Irish soda bread.
4. Olives
Olives are one of the most popular fermented foods. Their natural saltwater fermentation makes them rich in a family of bacteria called lactobacillus, which are beneficial for gut health.
Discover the health benefits of olives.
Add salty olives to our chicken and olive casserole, cod with olives and crispy pancetta and tuna, olive and spinach spaghetti.
5. Sourdough
Typically made from just four ingredients – flour, water, salt and a starter culture – sourdough is easy to digest and highly nutritious. It’s the starter combined with the long fermentation that holds the key to sourdough’s taste, texture and health credentials.
The starter is a mixture of flour and water, fermented by wild yeasts and lactic acid bacteria, which gives the sourdough its rise. Traditional sourdough undergoes a slow fermentation, which makes its vitamins and minerals more accessible. The process also kickstarts the breakdown of gluten, making the bread easier to digest.
Although the beneficial bacteria in the starter are lost during baking, compounds called polyphenols become easier for us to access. These act as a fuel source for the good gut bacteria we already have and, unlike many commercially produced loaves, sourdough helps keep blood sugar levels stable.
Discover the health benefits of sourdough.
Give sourdough a go with our step-by-step recipe to make your own starter, and use it to make our classic sourdough loaf.
6. Apple cider vinegar
Apple cider vinegar is made by crushing apples and allowing yeasts to ferment the natural sugars into acetic acid. It’s the unfiltered vinegar that retains the benefits because it contains the ‘mother’, a collection of proteins, enzymes and friendly bacteria. You’ll recognise an unfiltered product when you see it because it will appear cloudy in the bottle.
Including apple cider vinegar in your diet may help improve fasting blood sugar and reduce HbA1c, a marker your doctor may check because it gives an indication of your long-term blood sugar control.
Discover the health benefits of apple cider vinegar.
Use apple vinegar to make our spicy black bean tacos.
7. Sauerkraut
Sauerkraut is essentially fermented cabbage and is thought to have originated in China more than 2,000 years ago. The process of fermentation initiates certain beneficial bacteria and it’s these, along with the process itself, that makes sauerkraut such a healthy choice.
Fermented cabbage is especially heart-healthy, being fibre-rich and a source of beneficial bacteria that help to balance cholesterol levels. It’s also a good source of potassium, and its bacterial content is thought to positively influence blood pressure.
Discover the health benefits of sauerkraut.
Make your own sauerkraut with our easy recipe.
8. Kefir
Kefir may be even better for you than yogurt. This is because it benefits from a more wide-ranging composition of beneficial bugs and yeast. These microbes are responsible for producing bioactive compounds that have numerous benefits for our health, from improving digestion to lowering cholesterol.
If you follow a dairy-free or vegan diet you can still benefit from the health-promoting effects of kefir – water kefir is made by adding kefir grains to a sugary water solution, creating a slightly fizzy drink that is typically flavoured with fruits and spices.
Discover the health benefits of kefir.
Enjoy kefir in our raspberry and kefir overnight oats and kefir breakfast smoothie.
9. Kimchi
A fermented combination of vegetables and spices, kimchi is a traditional Korean food now popular across the world. The process of fermentation, by mainly lactobacillus bacteria, is thought to enhance the nutritional value of kimchi. This is because the bacteria themselves synthesise vitamins and minerals, and the process of fermentation deactivates some less favourable compounds.
Including kimchi regularly in your diet may help you manage cholesterol and balance blood sugar levels.
Discover the health benefits of kimchi.
Add the bold flavour of kimchi to our kimchi fried rice, kimchi noodles and kimchi scrambled eggs.
10. Kombucha
Kombucha is a mildly fizzy fermented drink made from sweetened tea and a specific culture known as a ‘scoby’ (a symbiotic culture of bacteria and yeasts). The bacteria and yeast in the scoby convert sugar into ethanol and acetic acid. The acetic acid is responsible for kombucha’s distinctive sour taste and makes it a great alternative when you fancy something a little different.
Kombucha contains small amounts of vitamins and minerals, including vitamin C and vitamins B1, B6 and B12, which are produced when the yeast breaks down the sugars. Levels are likely to vary by product.
Discover the health benefits of kombucha.
Make your own kombucha with our easy recipe.
11. Miso
A traditional ingredient in Japanese and Chinese cooking, miso is made from soybeans and grains that are fermented by koji enzymes and beneficial bacteria. Miso is rich in gut-friendly bugs, protein and vitamins E and K, as well as plant compounds called isoflavones, which may have anti-cancer benefits.
Discover the health benefits of miso.
Use miso to make our miso aubergines, miso salmon with ginger noodles and miso chicken and rice soup.
12. Tempeh
A great protein alternative, tempeh is made from cooked, fermented soya beans. It’s rich in bone-friendly minerals including calcium, magnesium and phosphorus. In addition to this, the fermentation process breaks down compounds known as anti-nutrients, which may inhibit our uptake of some of these valuable minerals. This makes fermented foods like tempeh easier to digest and the nutrients they provide easier to absorb.
Discover the health benefits of tempeh.
Be inspired by our chilli tempeh stir-fry and tempeh traybake.
13. Natto
A traditional Japanese dish of fermented soybeans, natto is a rich source of good-for-you bacteria. It’s traditionally consumed at breakfast and has a beneficial effect on the gut. Containing as much as 100 times more vitamin K2 than some cheeses, it’s particularly useful for those at risk of poor bone health.
However, if you’re on blood-thinning medication, such as warfarin, you should refer to your GP or registered dietician before introducing vitamin-K-rich foods into your diet.
Learn more about natto and what makes the Japanese diet so healthy.
14. Kvass
A low- to no-alcohol lightly fermented drink from Eastern Europe, Kvass is traditionally made from dark rye bread, sugar, yeast, water and raisins. The flavour is often likened to a sweet, low-alcohol beer, with the fermentation process being triggered by wild yeasts and bacteria from key ingredients such as the rye.
When buying commercial Kvass you should be aware that it’s often made from malted barley and may be carbonated. Check the label to assess whether it has been subject to a fermentation process; if not, it will offer limited health benefits.
Where can you find fermented foods?
Fermented foods are widely available in supermarkets and health food stores as well as local farmers’ markets. Check out the chiller cabinets as well as the ambient aisles and look online for specialised cultures, including kefir grains and scoby. The likes of kimchi, kombucha and kefir are easier to find than you might first think.
Find out how to make kombucha.
What to look for on the label of fermented foods?
First off, always read the label and look for key words such as ‘live cultures’, ‘bio cultures’, ‘active cultures’ and ‘raw’ or ‘unpasteurised’. Many of these products will require refrigeration and will have a limited shelf life. A product with a shelf life that extends to months rather than a few weeks is unlikely to contain beneficial probiotic microbes. That’s because microbes are living organisms and may be damaged by long storage times and high temperatures such as those used during pasteurisation and cooking. That said, not all fermented foods need to be kept in the chiller cabinet – kombucha, miso and fermented sauces may be found in the ambient aisles of your local supermarket.
The ingredient list on the label should also be simple, with a limited number of items listed. Avoid products with added sweeteners, acidity regulators and preservatives. A final tip is look for products that are minimally processed and have been made using traditional methods, such as pickles made in a salt water brine rather than vinegar.
Enjoyed this? Now try…
4 signs you have an unhealthy gut (and what to do to help it)
Top 10 probiotics foods to support your gut health
Digestive health recipes and tips
Gut-friendly recipes
How to make kefir
How to make kombucha
Have you buying tips to share? What do you look for when selecting fermented food products? Let us know in the comments below.
This page was reviewed on 5 January 2026 by Kerry Torrens.
Kerry Torrens BSc. (Hons) PgCert MBANT is a registered nutritionist with a postgraduate diploma in Personalised Nutrition & Nutritional Therapy. She is a member of the British Association for Nutrition and Lifestyle Medicine (BANT) and a member of the Guild of Food Writers. Over the last 15 years she has been a contributing author to a number of nutritional and cookery publications including Good Food. Find her on Instagram at @kerry_torrens_nutrition_
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