Are prescription probiotics worth the money?

A well-nourished gut has become as coveted a health goal as completing the rings on your Apple Watch, so Dr Megan Rossi puts personalised probiotic prescriptions under the microscope

We suspect you could correct an erroneous pronunciation of lactobacillus. You may have even considered brewing your own kombucha, and you’re in good company around here if you’re just a little bit turned on by talk of ‘live cultures’. For a subject that’s got a lot to do with poo, gut health is pretty sexy these days, and, with links to good digestion, mental wellbeing and a strong immune system, you can see why. Probiotic supplements themselves are nothing new – evidence suggests that they help support the natural balance of bacteria in your gut when it’s been disrupted by treatment or specific illnesses – but some companies are now claiming that a personalised approach is best. The promise is that, for around a hundred quid (granted, a hefty price tag) and a stool sample in the post (did I just say gut health was sexy?), they can identify which bacteria you’re lacking and prescribe a probiotic supp unique to your needs. If it sounds too good to be true, that’s because it probably is – for now, at least. There’s evidence to support taking probiotic supps in certain scenarios. During a course of antibiotics, they can support your gut defences, which will be dampened by the drugs, helping to prevent diarrhoea*. And, if you suffer from IBS, they could help reduce symptoms, although it’s not certain which strains are effective*. Also, some varieties could help keep tummy trouble at bay when you’re travelling abroad*. But scientists are yet to prove for certain what the specific benefits are for healthy people. The problem? A family of probiotics – such as lactobacillus – contains hundreds of different strains, each of which can have a hundred different functions in the body. Testing every one is impossible, at least with existing technology, as each strain is constantly changing. And even the stuff we know to be ‘good bacteria’ doesn’t have an RDA, meaning we don’t know the optimal amount. So no lab – no matter how much you pay – can assess exactly what you might be missing in order to top you up accordingly. As for the idea of ‘microbiome dysbiosis’ – or unbalanced bacteria – it’s basically fake news. So, if we’re not there yet, where are we? Scientists are using stool samples to build on their knowledge of bacteria levels in the gut. Then there are faecal transplants – which involve (brace yourself ) a poo sample from a healthy donor being inserted into the body of an ill person – used to treat a severe illness called clostridium difficile infection. But forking out for your own army of bacteria? Nice, but, like monogrammed luggage, probably not worth the money. What, then, can you do for your gut bacteria? Well, eating a wide range of fruit, vegetables, nuts and seeds has a prebiotic effect, which means that your gut bacteria feed off their dietary fibres. Fermented foods can also be helpful. Like probiotic supplements, there isn’t clinical evidence yet to show that the live cultures in foods like kimchi, sauerkraut and kombucha have any real impact on your microbiome, but if you like the taste, what’s the harm? My advice? Sip on some kefir and sit tight until the science catches up.