From kombucha to kefir, fermented foods are growing in popularity and there's increasing evidence that including them in your diet can improve your gut health.
What are fermented foods?
Fermented foods (and drinks) have been through the lacto-fermentation process, which means that naturally occurring good bacteria (lactobacillus) feed on the sugar and starch within the food creating lactic acid.
As well as preserving the food and altering the flavour, this process also unlocks its enzymes, B vitamins, omega-3 fatty acids and probiotics – all of which are what you need to maintain a healthy and balanced gut.
How do fermented foods help your wellbeing?
The boost that fermented foods give your gut is essential for your wellbeing. "Your gut is the centre of your being - it digests and assimilates nutrients from the food that you eat," explains Robyn Youkilis, author of Reset Your Gut. "It's where the majority of your immune system resides, and it also plays an important role in mood and hormones."
In fact, research has shown that your gut health (and what you eat) can also have a big impact on your mood. Our brains and guts are linked by a complex network of neurons, hormones and chemicals that provides feedback to the brain on how hungry we are.
The connection works both ways and stress and anger can also affect the gut, particularly if you suffer from conditions such as Irritable Bowel Syndrome or 'leaky gut syndrome'.
What are the benefits of eating fermented foods?
Include a bit of sauerkraut, kimchi and kefir or other fermented foods in your diet. The boost they'll give your gut bacteria has been found to result in a wide range of health benefits, but there are other reasons to eat them regularly too…
They can improve your digestion
Some of the sugars and starches in fermented foods have been broken down and so are easier to digest, helping to alleviate bloating, gas and heartburn.
They boost your immune system
A staggering 70-80 per cent of the immune tissue is located within your digestive system. Fermented foods help by supporting the mucosa (gut lining) which acts as a natural barrier, making the immune system more robust.
In addition, the cabbage used in sauerkraut contains glucosinolates, which have been shown in laboratory research to have anti-cancer activities. These glucosinolates are destroyed by cooking and pasteurisation but not by fermentation.
They help you lessen the amount of sugar you consume
Fermenting reduces the sugar levels in your food. This is because the bacteria, present during the fermentation process, essentially eat the sugar for you!
They make you more able to access nutrients
Fermentation can increase the availability of vitamins and minerals. In particular, promoting your ability to manufacture B vitamins and synthesise vitamin K.
They have mood-boosting properties
Studies have shown that there is a link between the gut and brain. The gut is lined with neurons that can influence our emotions and feelings.
Serotonin – the 'happy' neurotransmitter – is made in the gut and research further suggests that as probiotic bacteria can contribute to a healthy gut, they are also linked to a better mood.
They help your body get rid of toxins
Some natural compounds that interfere with the absorption of nutrients can be removed by fermentation. For example, the phytic acid found in legumes and seeds, binds minerals such as iron and zinc, reducing their absorption when eaten.
How often should we eat fermented foods?
There are lots of different opinions on this. If you're new to fermented foods, it's best to try them a couple of times a week and build up to almost every day.
You could try a couple of spoonfuls of sauerkraut, kimchi or umeboshi (Japanese fermented fruits) with a meal (or two) per day and top up with a fermented drink such as kefir or kombucha.
Generally fermented foods are beneficial for everyone, including during pregnancy. However, if you have Candida (a fungal overgrowth in the gut), you should avoid eating fermented foods.
What are the best-known fermented foods?
Apple cider vinegar
Unpasteurised cider vinegar helps your digestive system and encourages friendly gut bacteria, plus it's high in potassium and minerals. Don't be worried if it looks cloudy - it's meant to be!
This fermented drink can be made from dairy or coconut water using live kefir grains grown in liquid.
This Korean fermented cabbage has more spice than sauerkraut.
This Japanese paste is made from rice and koji – a mould. It has a savoury umami flavour and can be added to dressings.
This is a fermented tea, thought to have originated centuries ago in China. Drink it for a boost of vitamins B and C.
This drink from Eastern Europe is made with stale bread or beetroot.
Miso paste from Japan is traditionally made from fermented soy beans and is high in potassium. It comes in many varieties, but most are robust in flavour – add it to soups, stews and sauces. If soy isn't for you or you have an intolerance, try chickpea miso.
This traditional breakfast food from Japan is made with steamed or boiled fermented soybeans.
Essentially a cake made of soybeans, this is a great source of amino acids and B vitamins. Probiotic yoghurt Natural, unsweetened is best - dairy, soy or coconut. Make sure you stir in the whey (the watery bit at the top) as it holds the best nutrients (Lacto-bacillus Acidophilus).
You can make fermented pickles from most vegetables and it's surprisingly easy to do. Simply take your vegetables of choice, pack them into a sterilised jar with some salt and fill with water. Leave them to ferment for at least three days, or until they reach your desired taste and firmness.
Where can you buy fermented foods?
Fermented foods are becoming more widely available in UK supermarkets: for example, Waitrose stocks kombucha, you can buy kimchi in Tesco, Holland and Barratt has apple cider vinegar including 'the mother' (the raw enzymes used in the fermentation process), while sauerkraut is available from many familiar outlets.
For more unusual fermented foods, try specialist supermarkets or online sources including Amazon. But to get the best possible health benefits from traditionally fermented foods, buy them in health food stores and make sure they are raw and do not contain vinegar.
The ingredients needed to make your own fermented foods, such as kefir cultures and grains, can also be bought online and in specialist shops.
Can you make fermented foods at home?
Though you can buy many different fermented foods ready prepared, they are most beneficial when prepared at home. Packaged varieties are often pasteurised, which kills off all the good bacteria. In addition, home-made versions are much cheaper.
Rebecca Sullivan, author of The Art of the Natural Home, says it's easy to make your own fermented foods at home: "Fermenting, pickling and preserving are all simple things which we've forgotten how to do, but once upon a time everyone had to do it themselves. Sauerkraut is the greatest of the superfoods in my opinion, and it's one of the easiest things to make - it's literally cabbage and salt. That is it."
She advises simply massaging the cabbage with salt to bring out all of the brine, which then ferments the cabbage. Use wide-mouth glass jars for fermenting so you can easily pack in your vegetables.
Sterilise the jars before use to avoid growing the wrong type of bacteria during the fermentation process, which could make you ill.
Heat the oven to 180C/160C fan/gas 4, wash your jars and lids well in warm soapy water and dry thoroughly with a clean tea towel.
Put the jars on a shelf in the oven for 15 minutes then remove with oven gloves. Leave to cool and they are ready to fill. For more details on home fermenting, go to www.bbcgoodfood.com and for some quick and easy recipes, see below.
4 fermented food recipes to try at home
Sauerkraut originated in Germany and is a dish of chopped, fermented cabbage. It has a soft texture and a mild, slightly acidic flavour that is great with meat. It's is a good form of dietary fibre and contains vitamins C and K, potassium, calcium and phosphorus.
As well as its gut-friendly properties, the cabbage itself is packed with isothiocyanate compounds, which have cancer-fighting properties. The yeasts and bacteria needed for fermentation are already present on cabbage leaves so the only added ingredient required is salt. You can buy sauerkraut in many supermarkets.
Go for the unpasteurised version if possible – or make your own at home for a fraction of the cost by following this recipe.
Korean favourite, kimchi, is a combination of cabbage and carrots and other vegetables fermented in a spicy sauce made from garlic, ginger and shrimp paste – and sometimes chilli.
When salt is added to the cabbage, it triggers the lacto-fermentation process, as in sauerkraut. Kimchi is eaten as a side dish; or as whole leaves used as wraps for meat, fish or shellfish; or as a condiment for other meals.
Try the recipe here - it should keep for up to three weeks in a sealed container in the fridge.
A popular fermented back or green tea drink with added health benefits, kombucha is lightly sparking, a touch sour and ever-so-slightly alcoholic. Its origins are thought to be in China, but is has also been traditionally drunk in Russia and eastern Europe.
Kombucha is made by adding a SCOBY (which stands for a symbiotic culture of bacteria and yeasts) to sweetened tea, which has been allowed to cool. It's left to ferment for about a week before being transferred to another container with more sugar. Spices or fruit can be used to flavour it at this point.
This fruity Mexican drink created by Robyn Youkilis is very refreshing to drink in the hot summer months.
Tepache originates in Mexico and South America. It's refreshing by itself, but is often used as a base for cocktails or mocktails!
6 top tips for introducing fermented foods into your diet
- Add natural bio yoghurt to your fruit and granola at breakfast - it's an easy way to start your day with a good dose of probiotics.
- Try adding a side order of sauerkraut (fermented cabbage) to your meat dishes.
- Swap one or two of your daily tea, coffee or fizzy drinks for tangy kefir (fermented milk) or mildly sparkling kombucha (fermented tea).
- Use raw apple cider vinegar as a salad dressing or in the form of a drink, to promote healthy digestion.
- Sip fermented drinks, such as fruity tepache (a Mexican drink made from the peel and the rind of pineapples), for a great - and refreshing - accompaniment to any meal.
- Boost your lunchtime salads or soup during the winter with a dash of spicy kimchi (Korean fermented cabbage).