How ‘live’ food gives you a good gut feeling

Eating sauerkraut and other fermented dishes makes for a healthy body and a well-functioning brain. Xanthe Clay explores the science behind it

Has a year of lockdown left you feeling not as sharp as you were? If so, one way to boost your brain power – and your mood – could be to add some sauerkraut to your supper.

Unless you’ve been hiding under a packet of Pringles for the past five years, you’ll know that these days, good health is all about the little things – microscopic in fact. In the late 1990s the term microbiota was coined to describe all the microbes – bacteria, fungi, protozoa and (yes) viruses – and their genes that live on and inside the human body. Weighing a total of around 2kg, there are about 10 times as many microbes as cells in the human body. It’s the ones in our gut that get most attention, as a healthy, diverse mixture of the right microbes performs many useful jobs, including helping digest food, regulating the immune system, reducing inflammation, protecting against disease-causing bacteria, and producing vitamins.

Increasingly, scientists are convinced that a fit microbiome is the key not just to a healthy body but to a well-functioning brain. It’s even had the seal of approval from Dr Michael Mosley himself – a sure sign that that this has gone from wacky fringe-thinking to mainstream.

In Mosley’s Radio 4 show Just One Thing, a compendium of easy fixes for good health, he describes, along with scientist Kirsten Berding Harold from University College Cork, how eating live sauerkraut, and other live fermented foods like kimchi and kefir, can boost our gut microbiome and help with sleep and mood. The live probiotics in the foods, along with healthy prebiotics (see box, left) seem to work in part by supercharging the immune system and by their anti-inflammatory effect. There’s still research to be done, but a study released last year by Monash University in Australia pointed out that inflammation underlies many conditions – obesity, type 2 diabetes, inflammatory bowel disease – and concluded that some people’s microbiota appears to have antiinflammatory properties, furthering the case for probiotic and prebiotic therapies.

But hang on – everything we eat has to go through our stomachs, where powerful acids break it down. How can the microbes survive that and inhabit our intestines? I turned to Dr Caroline Gilmartin, microbiologist turned ferment-maker (everygoodthing.co.uk ) for an answer. “It’s not terribly well researched actually,” she told me, “but food can be protective, metabolising sugars can be protective, or microbes may use other mechanisms like ‘chaperone proteins’ to carry them through. Whatever happens, stool-sample analysis frequently shows that kefir microbes and other lactobacilli are present, so they do come out the other end.”

So how can we get some of this wonder food into our diet? First off, remember that “live” is an important word here. Fermented vegetables are sometimes referred to as pickles, which is confusing, as the term covers traditional British vinegar pickles too – which are generally made with pasteurised vinegar and very much not live. Sauerkraut on the shelf in the supermarket, sitting next to the pickled onions, is pretty healthy – low in fat and calories and one of your five a day – but it isn’t a source of live bacteria. But if the jar is in the chiller cabinet, and says “live product, keep refrigerated” on the label, then you’re on to the good stuff.

You can make your own sauerkraut of course, which involves chopping a kilo of cabbage, massaging it with 25g of salt until bathed in its own brine, then packing it into a jar and leaving it for a week or so. The internet is awash with instructions. But there are now lots of small fermenters around the country making the stuff beautifully, so why not start there? Buying a single jar makes sense too, as diving in too fast may upset your stomach. Start with a couple of spoonfuls and build up to three portions a day.

Once you’ve got hold of your sauerkraut, it’s tempting to turn to a traditional German recipe, and braise it with sausages. But delicious though this is, once the temperature of fermented food gets much beyond lukewarm, the microbes will perish. Gilmartin suggests adding in a little more fresh live sauerkraut just before serving, “or just on the side”. That’s eating clever.