These five fermented foods are the key to good gut health – here’s why

From kimchi to kombucha, discover the delicious varieties and surprising health benefits of fermented foods…

Fermentation is an ancient technique of preserving food that brings with it an array of other benefits.

Fermenting food involves the use of microorganisms, such as bacteria, fungi or yeast, in preserving foods and drinks. These microorganisms are hugely beneficial to our gut health.

But not all fermented foods are equal. To reap the health benefits, look for foods which are labelled ‘fermented’, or as containing ‘live cultures’ or ‘probiotics’.

How to introduce fermented foods to your diet

Although food was first deliberately fermented more than eight thousand years ago, many of us are trying these recipes for the first time. This means it can be tricky to know how to integrate them into our diets.

Because fermentation is a natural chemical process, many foods can be used, and the taste can vary. Experiment with different kinds to discover one you love.

When introducing fermented foods to your meals, keeping them cold or just above room temperature is the best way to preserve the health benefits.

Nutritionist Elena Holmes explains: “Unfortunately, heat kills bacteria and probiotics are not an exception.

“Gently cooked fermented foods still retain some of the vitamins and prebiotic fibres, taste nice and are easily digested.”

It’s also important to look at the salt content of fermented foods, as recipes can vary from containing none at all to much higher levels.

For example, some kimchi recipes require rinsing the salted cabbage before adding other ingredients, while miso will often contain a high concentration of salt.

When adding saltier fermented foods to a dish, the overall amount could be balanced by not adding any additional salt to that meal.

What makes fermented foods so good for us?

According to Dr Sunni Patel, the expert behind gut health website Dish, Dash, Deets, fermented foods provide an array of probiotics to the digestive system which give a boost to the beneficial microorganisms in our guts, helping them to neutralise the harmful ones.

This strengthens the intestinal barrier and helps to improve the absorption rate of nutrients, benefitting the body beyond the gut too.

Dr Sunni says: “A well-maintained gut, supported by fermented food, is an important part of keeping our brains, bowels and metabolic systems healthy, and can boost immunity.

“On top of that, fermented foods such as kimchi are also often high in fibre, vegan vitamin B12 and folate – making them excellent dietary allrounders.”

As an added bonus, the process of fermentation usually alters and enriches the original food, making it tastier and healthier.

But that’s not all. Different types of fermented foods offer different benefits to our health and there are thousands of different varieties to discover.

To make it easy, we’ve rounded up some of the most common fermented foods and their health benefits:

Benefits of eating sauerkraut and kimchi

These popular fermented cabbage dishes are produced by lactic acid fermentation.

The vegetables are finely cut and salted before being submerged in water, allowing the naturally-present bacteria to feed on the vegetables’ carbohydrates and produce lactic acid. It’s this that preserves the food and produces its sour taste.

The bacteria also produce vitamin K and some B vitamins, increasing its nutritional value.

When you eat sauerkraut or kimchi, you also eat the lactic acid bacteria, which make themselves at home in your colon and help you to digest food.¹

In fact, fermented veggies lower gut inflammation because they supply beneficial bacteria that have a soothing effect on the gut wall.

Sauerkraut is a great source of vitamin C, vitamin K and iron as the fermenting makes them more bioavailable. It also contains some calcium, manganese, B vitamins and is an excellent source of fibre.

To get the most benefits from sauerkraut, eat it raw because cooking not only destroys vitamin C, it also kills all the good bacteria.

Kimchi is usually made from salted Chinese cabbage (Chinese leaf) and other vegetables and is flavoured with garlic, chilli and ginger.

There are hundreds of varieties and each is a little different – many contain seafood or fish-based condiments, so always check the ingredients. It’s the fermented veggies that account for kimchi’s many benefits.

It’s an excellent source of beta carotene, used by your body to make vitamin A, it’s rich in vitamins C and K, and contains good amounts of calcium and iron.

Both kimchi and sauerkraut are made from cabbage and all veg from the cabbage family have anticancer properties.²

They are also anti-inflammatory and antioxidant and so help to protect your overall health.

Combined with medical treatment, these foods can even help to combat the helicobacter pylori stomach infection.³

Benefits of eating tempeh

Tempeh is made by the fermentation of soya beans, a process that binds them together in a cake-like form. It involves soaking the beans for several hours, cooking them and then allowing them to ferment with the fungus rhizopus oligosporus.

The result is soft soybeans bound together by white mycelium (thick web of fibres) from the fungus.

Before eating, tempeh needs to be cooked and flavoured and is usually fried or smoked.

Because tempeh is made with whole soya beans, it retains all their nutrients and is therefore a good source of protein, healthy fats, carbohydrates, fibre, B vitamins (but not B12), vitamin K, iron, calcium, magnesium and some other minerals.

The plant-based protein in tempeh is high quality and there’s a lot of it –a 100 gram serving of tempeh contains around 20 grams of protein!

During the fermentation process, the fungus releases enzymes that break down some carbohydrates in the soya beans, making them easier to digest.

The same fermentation also breaks down phytic acid – that reduces the absorption of minerals such as iron or calcium – and as a result, tempeh has low levels of phytic acid, allowing more of the minerals to be absorbed.

Enjoy the tastiest benefits of fermented foods with these vegan tempeh recipes

Health benefits of miso

This traditional Japanese seasoning is produced by fermenting soya beans with salt and koji – rice fermented with the fungus aspergillus oryzae – over a long period of time.

To make koji, aspergillus oryzae is mixed with steamed rice and the fungus produces enzymes that break down rice starches into sugars, and proteins into amino acids.

Koji is then combined with cooked, crushed soya beans and salt and that starts a second fermentation in which the koji enzymes break down soya proteins, starches and fats into readily digestible amino acids, sugars and fatty acids.

The sugars in this mixture support the growth of lactic acid bacteria, which ferment the sugars and produce acid, giving rise to the characteristic umami flavour.

The final product, miso, is a thick paste rich in amino acids, iron, magnesium, manganese, zinc, several B vitamins and vitamin K.

It also contains millions of health-beneficial bacteria that help to improve your gut health. The only downside to miso is that it also contains high levels of salt, so don’t use it in large quantities.

Thanks to some of the fermenting bacteria, miso contains small amounts of vitamin B12, but it’s not enough to be your only source.

Benefits of drinking kombucha

This unique drink is made by adding bacteria and yeast to sweetened tea and allowing it to ferment for several days.

The bacteria and yeast feed on the sugar, producing acetic acid, other acidic compounds and gases that make kombucha fizzy.

All the microorganisms combined together form a floating blob, also called SCOBY (symbiotic culture of bacteria and yeasts), which can be used to ferment new kombucha.

The acetic acid in finished kombucha has antibacterial properties and can support treatment of bacterial infections and those caused by candida yeasts.

However, the acid doesn’t affect the fermenting bacteria so by drinking kombucha you’re taking in all those good bacteria that can help to improve your digestion.

Kombucha made from green tea is also a great source of antioxidants.

Can everyone enjoy the benefits of fermented foods?

Fermented foods are high in histamines, which are normally broken down by digestive enzymes, but some people don’t produce enough and have histamine intolerance.

As a result, histamine is absorbed into the bloodstream and may cause a range of unpleasant symptoms. If you know you have histamine intolerance, fermented foods are, sadly, not for you.

Discover more tasty and beneficial food preservation methods

Featured photo © ollo via Getty Images

References:

1. Leeuwendaal NK, Stanton C, O’Toole PW, Beresford TP. 2022, Fermented Foods, Health and the Gut Microbiome. Nutrients. Accessed via: ncbi.nlm.nih.gov/pmc/articles/PMC9003261/
2. Mandrich L, Caputo E. 2020, Brassicaceae-Derived Anticancer Agents: Towards a Green Approach to Beat Cancer. Nutrients. Accessed via: ncbi.nlm.nih.gov/pmc/articles/PMC7146209/
3. Fahey JW, Stephenson KK, Wallace AJ. 2015, Dietary amelioration of Helicobacter infection. Nutr Res. Accessed via: ncbi.nlm.nih.gov/pmc/articles/PMC4465045/