Only those whose primary residence is under a rock is unaware of the gut health revolution by now. It’s time to try making the four k’s at home: kombucha, kefir, kraut and kimchi.

Anyone with even the most passing of interests in health and wellbeing has, by now, got the memo loud and clear that the microbiome is key when it comes to ensuring that our bodies are fit, well and functioning at their optimal peak. We know that there are beneficial and harmful bacteria that can live in our guts, and that the way to encourage the good guys to take up residence in our gastrointestinal system is to eat the rainbow, aiming for thirty different plants – including herbs, nuts, seeds and spices – each week. As ‘diets’ go, it is an encouraging one: the idea is to eat more delicious and polyphenol-rich foods, not fewer. Do note though, it isn’t an invitation to consume as much as possible: anything too processed can play havoc with our microbes.

One other way of encouraging the good bacteria in is to include fermented foods in our diets. These are natural probiotics that have live microbes in them, which can be seriously beneficial to our guts, as pioneering scientist and patron saint of all things microbiome Tim Spector explains here.

It is, as he says, all about the four k’s: kimchi, kombucha, kraut and kefir. If you’re curious about how to make your own and incorporate these gut-friendly foods into your diet, do take a moment to read Biome’s introduction on how to ferment vegetables at home; as Sally Fallon of Nourishing Traditions says, ‘The proliferation of lactobacilli in fermented vegetables enhances their digestibility and increases vitamin levels. These beneficial organisms produce numerous helpful enzymes as well as antibiotic and anti-carcinogenic substances. Their main by-product, lactic acid, not only keeps vegetables and fruits in a state of perfect preservation but also promotes the growth of healthy flora throughout the intestine.’ And happily none of it is as complicated as it sounds. As a rule of thumb, you’ll need a kilner jar, some sea salt and your ingredients.

To get started, we’ve put together our favourite fermenting recipes for each gut-loving K – but don’t, meanwhile, forget full fat yogurt or good quality cheese, which also have the same effect.


Kimchi is the national dish of Korea and is typically made with cabbage, although you can use almost any vegetable. Sour and spicy, it makes a great addition to toast or noodles. The BBC Good Food’s quick recipe is an excellent way to get started with this tangy treat for the gut. (Do note, vegetarians and vegans may ditch the optional fish sauce). If, however, you have hours on your hands, why not try Olive’s more elaborate recipe, which it recommends setting aside a leisurely weekend for?


For Emma Christensen, it wasn’t the health benefits of kombucha per se that had her hooked. Rather, she says, ‘It was the way it tasted: like tart green apple mixed with sour stone fruits, but with an underlying sweetness that keeps it all together. And fizzy! I couldn’t believe that something this delicious could actually be made from tea, of all things. Or that I could make it at home with a few very basic ingredients.’

As she explains, kombucha starts out as a sugary tea, which is fermented thanks the use of a SCOBY – or, to use its full name – a symbiotic culture of bacteria and yeast. But if sugar sounds like an odd place to start for a gut microbe treat, fear not; the yeast, alongside the SCOBY, will devour most of it, leaving you with a low calorie slightly fizzy tea full of probiotics that your gut will love. All you will need, aside from your kilner jar and SCOBY, is water, sugar, a few bags of black or green tea, and some starter tea from your last batch, or simply shop-bought kombucha. You can then add fruit and flavourings as you wish. Find the full recipe here.


As Great British Chef’s Karen Burns Booth points out, kimchi has a been basking in the spotlight for a little while now, but what of its ‘humble cousin’ sauerkraurt? Whether you use it liberally sprinkled all over a hotdog or to top your salads with for some welcome crunch, it is so simple to make – and can even keep in the fridge for a whole year. All you need is a white cabbage, some carraway seeds, sea salt and juniper berries. It may not be as exotic as kimchi, but it’s every bit as tasty, as well as being simpler to concoct. Find the full recipe here, and then immediately check out Burns Booth’s recipe for polish sausage and sauerkraut casserole with beer here. Delicious.


Kefir is an incredibly versatile fermented drink traditionally made from cow’s or goat’s milk, although you can use water too. As well as containing probiotics that are excellent for the gut and for digestion, kefir is a natural source of protein, calcium and B vitamins, too. Thanks to its yogurt-like flavour, you can eat it for breakfast with fruit, in smoothies or use it in savoury recipes, as you might tzatziki. Drizzle it over salads, bake it into soda bread – or even into a cake. Happily, the recipe is super simple. All you need is milk (plant-based works as well as dairy), kefir grains and a slice of lemon. Find the full recipe here.

By Nancy Alsop
July 2022

Nancy Alsop


Nancy is a magpie for the best in design and culture.