Irritable Bowel Syndrome and Probiotics – worth a shot?

In medicine, you often know something is common or important if it gets its own TLA,  or Three Letter Acronym. Irritable Bowel Syndrome, or IBS, is both. Up to 1 in 5 people in the UK get it at some point, and it causes huge distress and disability. Yet without a ‘cure’, many people are left in limbo, searching for relief.

Sufferers will try, it would seem, pretty much anything – or at least an average of 5 products a month (1). And among the most popular non-prescription remedies if probiotics. These ‘good bacteria’ have taken the world by storm – the global market is estimated to be about $32 billion a year, set to rise to $42 billion by 2016. Studies have been done looking at the impact of probiotics on everything from boosting the immune system to ‘promoting digestive health’ to treating digestive disorders like IBS.

The theory is simple. We need bacteria to digest our food, and we have trillions of them (2,3). All bacteria may be equal, but some are most definitely more equal than others. These bacteria help us to break down food in the gut, but some produce more gas than others as a by-product of digestion. The wrong proportions of bacteria could mean less effective breakdown of foods or breakdown by the wrong bacteria, resulting in wind, bloating and abdominal pain (1,4).  In IBS, there is evidence that the gut bacteria in the gut are significantly different than in people who don’t have the same symptoms (5). The ‘good’ bacteria also compete for food with bacteria that could cause infections, helping to keep them in check and possibly to ward off infections. In theory, by using probiotics we tip the balance in favour of ‘good’ bacteria.

But for a probiotic to work it needs to fulfil three tasks

  • To ‘arrive’ in the digestive system in a high enough amount to have an effect
  • To ‘survive’ the decidedly hostile environment of the stomach, with its high concentration of acid
  • To ‘thrive’ in the gut, where it is needed, by getting through the digestive process in good shape.

A recent scientific study has looked at all these three factors (6). The researhers compared a wide range of widely available probiotics and the results, to my mind, made for surprising reading. All the tablet versions of probiotics (Align, Biobalance Support, Biokult, Probio7) failed all three tests – fewer than ¾ of the initial bacteria were alive and functioning when they were first taken; they didn’t survive stomach acid in any significant number; and those that did survive showed little sign of growth once they had passed through the stomach. By contrast, liquid Symprove and powdered VSL-3 reached the area of the gut where they were needed and were able to multiply. Actimel found the acid of the stomach content hard going but did bounce back.

This study does not look at what happens in real life, but it’s one of few ‘head to head’ studies comparing several probiotics. The acid test, of course, is whether a probiotic improves symptoms compared to ‘placebo’ – in a trial where neither the doctor nor the patient knows if they are getting the ‘real thing’ or a sham medicine. Both Symprove (7) and VSL-3(8) have survived the acid test.

Are these options the answer to every IBS sufferer’s prayers? Almost certainly not – IBS is a complicated condition and every patient is different. But these studies do help us to understand what is well worth a try, and where we could be throwing good money after bad.


  1. Research Now (2014) Survey of 1029 IBS sufferers
  2. Guarner, F; Malagelada, J (2003). "Gut flora in health and disease".The Lancet 361(9356): 512–9.
  3. Steinhoff, U (2005). "Who controls the crowd? New findings and old questions about the intestinal microflora".Immunology Letters 99(1): 12–6.
  4. Gibson, Glenn R. (2004). "Fibre and effects on probiotics (the prebiotic concept)".Clinical Nutrition Supplements 1(2): 25–31.
  5. Kassinen A, Krogius-Kurikka L, Makivuokko H, et al. The fecal microbiota of irritable bowel syndrome patients differs significantly from that of healthy subjects. Gastroenterology 2007; 133: 24–33
  6. Fredua-Agyeman, M & Gaisford, S., (2014). Comparative survival of commercial probiotic formulations: Tests in biorelevant gastric fluids and real-time measurements using microcalorimetry. UCL School of Pharmacy, University College London.
  7. Sisson, G., Ayis, S., Sherwood, R., Bjarnason, I., (2014). Randomised clinical trial: a liquid multi-strain probiotic vs. placebo in the irritable bowel syndrome – a 12-week double-blind study. Aliment Pharmacol Ther. 40:51–62. 
  8. Kim HJ, Vazquez Roque MI, Camilleri M, Stephens D, Burton DD, et al. A randomized controlled trial of a probiotic combination VSL#3 and placebo in irritable bowel syndrome with bloating.Neurogastroenterol Motil.2005;17:687–696

Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. Patient Platform Limited has used all reasonable care in compiling the information but make no warranty as to its accuracy. Consult a doctor or other health care professional for diagnosis and treatment of medical conditions. For details see our conditions.


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