Fermented foods for gut health

Taking care of your gut is still reigning supreme. We're finding out more things about how our gut affects the rest of our body all the time. And currently on our list are the potential benefits of fermented food – so let’s dig in.

When we talk about fermentation in food, we’re talking about the use of microorganisms – like yeast or bacteria – to alter food and turn it into something delicious. Fermentation is the process which helps turn sugar into wine, beer or cider, as well as helping dough to rise. Some fermented foods contain live microorganisms, which may interact with the gut microbiota.¹

Research into the health effects of fermented foods is growing, although the evidence varies between different foods, it's generally agreed that fermented foods could be considered an important part of any diet.² If you want to introduce fermented food and drinks into your diet, it can be hard to know where to start. Luckily, we’re on hand to help.

1. Kefir

Kefir is a fermented dairy drink that in Turkish, is derived from the word ‘keif’ which means ‘good feeling’. It originated in the Caucasus Mountains and Tibet.³ People make kefir by using starter grains called kefir grains, which contain live microorganisms, including lactic acid bacteria and yeast. It also contains essential minerals, vitamins, amino acids and enzymes.³ When it comes to kefir benefits, early clinical studies suggest it could potentially support gut function in adults, although exactly how kefir affects the body isn’t yet clear.⁴ There's a vegan alternative to traditional dairy-based kefir called water kefir. One 2021 study showed that while water kefir lacks protein, it may be a source of live microorganisms.⁵

2. Yoghurt

Yoghurt is one of the best and most well-known fermented foods. It’s made from milk that’s been fermented with live, friendly bacteria, namely  lactic acid bacteria. Introducing yoghurt into your diet is a good way to support your gut microbiome.⁶ Some studies have suggested that regularly eating some yoghurts containing live bacteria may help with gut health.^7,8 However, this all depends on the specific strains in the yoghurt, so make sure you’re buying the real deal and go for yoghurts with ‘live’ or ‘active’ cultures, as some yoghurts will have been pasteurised to kill the bacteria.

3. Cheese

Most cheese has been fermented but doesn’t always contain live microorganisms. This is because most of the cheese found in supermarkets will have been processed in a way that kills the live bacteria. Friendly bacteria can sometimes survive the ageing process in some cheese types though, including mozzarella, gouda, parmesan, grana padano, blue cheese, cottage cheese and cheddar.¹

While it’s not known exactly what the effects of eating cheese are on gut health, these cheeses may have positive effects on your gut microbiome.¹ Cheese can be high in saturated fat and salt, so make sure you eat it in moderation.⁹ Make sure you always check the label for live and active cultures if you want some bacterial goodness along with the protein, vitamins and minerals cheese provides.

4. Tempeh

Tempeh is originally from Indonesia but has become popular all over the world because of its high protein content and ‘meaty’, nutty and earthy taste.¹⁰ It’s made by fermenting soybeans with a specific type of fungus, which gives it its much-loved texture – plus, vitamin B12 is in some tempeh from associated live bacteria.¹⁰

5. Miso

Miso is another fermented soybean product from Japan and is most popular for its use in miso soup.¹¹ It’s traditionally produced by fermenting soybeans with a type of fungus called koji and salt, but it can also be made by mixing soybeans with rice, barley and rye. Unpasteurised miso is full of friendly live bacteria, as well as protein, fibre, vitamins and minerals, including vitamin K and copper.¹² Some studies have suggested that miso can support digestive comfort, but more conclusive research is needed.¹³ Miso is also vegan friendly but can be high in salt, so it's important to make sure that you eat it in moderation.

6. Sauerkraut

You may have already experienced sauerkraut on your frankfurter sausage or Reuben sandwich, which provides a deliciously sour and salty flavour. Vegan-friendly sauerkraut has been enjoyed by many European countries for centuries and is made by fermenting finely shredded cabbage with lactic acid bacteria.¹⁴ Sauerkraut is one of the fermented foods where there are clinical studies taking place. One such study from 2018 found that eating sauerkraut for six weeks could help digestive discomfort.¹⁵

7. Kimchi

Similar to sauerkraut, kimchi is another fermented vegetable dish (usually cabbage) but with a lot more seasoning. It’s made by fermenting cabbage or other vegetables with Lactobacillus kimchi and other lactic acid bacteria and then adding seasonings like red chilli pepper flakes, ginger, garlic, spring onion and salt.¹⁶ There have been a few studies into kimchi’s effects on the gut and preliminary evidence that kimchi may have an impact on the gut microbiota composition.¹³

8. Kombucha

Kombucha is one of the larger health food trends of the 21st century, despite having originated in Northeast China in about 220 BC and consumed extensively during the Qin Dynasty.¹⁷ Human research remains limited and it's not yet clear whether kombucha provides meaningful gut-health benefits outside of some potential effects on microbiota.¹³ Kombucha is made by fermenting black or green tea with bacteria and yeast. While traditional kombucha can be an acquired taste, you can get variations of kombucha where it's flavoured with fruits such as raspberry or lemon to make it more palatable. However, just be sure to check the label and see if it's pasteurised or not.

Fermented foods aren't going anywhere anytime soon. If anything, they'll probably just keep becoming more popular as there's choices for all diets. Plus, they can add a tasty boost to your everyday dishes. There's so much more to keep learning about the gut, like how to keep your gut healthy and how prebiotics can support your gut. 

Disclaimer – This article provides informational advice and is not a substitute for medical care. Working with experts for accuracy, we take great care to ensure the information is up-to-date and relevant. However, you should always consult your GP or healthcare professional before using supplements or alternative products, particularly if you have medical conditions or are under supervision.