Probiotics for irritable bowel syndrome (IBS): what UK guidance says

Irritable bowel syndrome is described by NICE CKS as a chronic, relapsing and often debilitating disorder of gut-brain interaction. The typical features are abdominal pain associated with a change in stool form or frequency, which may be related to opening the bowels and may come with bloating. The NHS lists the main symptoms as stomach pain or cramps that are usually worse after eating and better after a poo, bloating, diarrhoea and constipation, with days when symptoms are better and days when they flare up.

Probiotics are products that contain live micro-organisms, most often certain bacteria, which are intended to add to the bacteria in the gut. They are sold as capsules, powders and drinks, and the BDA also mentions yoghurt and fermented milk drinks such as kefir in this context. The NHS says probiotics may help any symptoms caused by changes in gut bacteria, which is why they sit in its list of things people with IBS can try.

It is worth being clear about what the guidance does not say. The pages read for this article treat probiotics as something that some people choose to try, not as a treatment prescribed for everyone with IBS, and none of them promises a particular result. The NHS opens its treatment page by saying that there is no single diet or medicine that works for everyone with IBS.

Three UK sources agree on the broad approach, which is to try a probiotic for a defined period and stop if it is not helping. They differ in how long a fair trial lasts.

Putting the three sources together gives a practical shape. Choose one product, take it every day as directed on the packet, and note your symptoms in a diary. The NHS and the BDA both recommend keeping a food and symptom diary when making changes, and the BDA suggests making one change at a time so you can see what has helped.

Give it long enough to judge. If you want to follow the shorter NHS and BDA timeframe, a minimum of four weeks is suggested. NICE CKS refers to at least twelve weeks for people who choose supplements. If you are not better by the end of your chosen period, the NICE CKS summary says to discontinue, and the BDA suggests you could try an alternative brand rather than adding several products together.

Avoid changing everything simultaneously. A diary is far more useful when you add a probiotic without also starting a low FODMAP diet, a new medicine and a stricter exercise routine in the same month. The BDA warns that you should give your bowels time to adjust to any changes.

Probiotics are only one small piece of IBS self-care. The NHS lists a healthy, balanced diet, keeping a diary of what you eat and any symptoms, drinking at least 8 to 10 drinks of fluid (around 1.5 litres) a day, finding ways to relax and getting plenty of exercise. It suggests not delaying or skipping meals, not eating too quickly, and not eating lots of fatty, spicy or processed foods.

For specific symptoms the NHS suggests eating oats such as porridge and up to a tablespoon of linseeds a day for bloating and cramps, cutting down on high-fibre foods and sorbitol-containing products for diarrhoea, and increasing soluble fibre and fluid for constipation. It suggests asking a pharmacist about medicines such as Buscopan, peppermint oil, loperamide or laxatives. The BDA adds that mindfulness, yoga and regular exercise may help with relaxation and that hypnotherapy or cognitive behavioural therapy could be tried if dietary changes and medicines have not helped.

If simple steps are not enough, the BDA says to ask your doctor for a referral to a dietitian, who may suggest a trial of a diet restricted in fermentable carbohydrates, known as the low FODMAP diet. NICE CKS gives specialist dietitian referral and various medicines as further options.

The NHS says to see a GP if you think you might have IBS and have had symptoms for over 4 weeks, so that they can check and run tests to rule out other problems. It also advises seeing a GP if diet changes and pharmacy medicines are not helping, or if you need to avoid lots of different foods to control your symptoms.

Some symptoms are not typical of IBS. The NHS says to ask for an urgent GP appointment or get help from NHS 111 if you have lost a lot of weight for no reason, are bleeding from your bottom or have bloody diarrhoea, find a hard lump or swelling in your tummy, or have shortness of breath, noticeable heartbeats and paler skin than usual, because these could be signs of something more serious. The BDA also lists a family history of bowel or ovarian cancer, and looser, more frequent stools persisting for more than six weeks in someone aged over 60, as reasons to discuss referral.

A probiotic should not be used to put off these conversations. If you are starting a supplement for symptoms that are new, severe or have changed, speak to your GP first.

The sources read for this page do not describe particular brands, and they do not recommend one over another. The BDA suggests simply trying one at a time and swapping brand if there is no benefit. NICE CKS refers to over-the-counter probiotic supplements, so most people buy them themselves. Ask a pharmacist if you have a medical condition, a weakened immune system or take regular medicines, because the sources here do not set out who should avoid them.

The BDA's IBS sheet points to its own food fact sheet on probiotics, which is a useful next read for the finer points of choosing between products.

On the NHS, IBS is usually diagnosed by a GP after tests such as a coeliac blood test and a poo test to rule out infection and inflammatory bowel disease. Dietitian referral is available when simple measures are not working, and the BDA notes that NHS dietitian webinars exist for IBS.

Some people see a private dietitian, which the BDA says can be found through its directory, usually to get personalised dietary guidance faster. NICE CKS refers to over-the-counter supplements, so the cost of the products themselves is likely to be the same either way. Make sure any private adviser knows your diagnosis and that red-flag symptoms have been checked.