Irritable Bowel Syndrome

Irritable Bowel Syndrome is a common disorder with challenging treatment

Findings in modern physiology are in full accord that nothing in our bodies act in isolation. No interaction is as surprising as the intimate dance between the beneficial bacteria of our gut and the delicate synapses in our brain, mediated by the microbiota-gut-brain axis.1,2 Who would have thought that the denizens of our gastrointestinal tracts are able to modulate some of our most sophisticated brain functions, such as memory, cognition and the stress responses?3 It is this close link between gut and brain that explains why sufferers of certain gastrointestinal disorders also present with high incidences of psychopathology, or why chronic stress can cause stomach ulcers.

Irritable bowel syndrome (IBS), the most common gastrointestinal disorder of our age, is no exception. For the approximately 11% of the global population that suffer from IBS4 – chronic abdominal pain, accompanied by bloating, flatulence, constipation and diarrhoea is not the sum of the debilitating symptoms. For many, this common set of gastrointestinal symptoms walk hand in hand with elevated levels of stress and anxiety5, changes in the activity of the hypothalamic-pituitary-adrenal axis6 and alterations in cognition patterns.7,8

Despite a clear picture emerging of the range of symptoms associated with IBS, the exact cause of the syndrome is still largely unknown. This complicates the treatment of this disorder. Consequently, frustrated physicians mainly end up treating the symptoms, without an inkling of the cause. To this end, several chemical drugs are employed that target specific symptoms, but none of them have satisfactory long-term effects on patients who may well spend a lifetime suffering from chronic IBS.9 Because of this, many patients turn to alternative remedies, with minimal success.9

Unlike these treatments, probiotics have proven themselves to be quite successful in alleviating general symptoms of IBS, with none to minor adverse effects even after long-term use.10,11 Indeed, even in healthy individuals, treatment with probiotics can improve memory and alleviate stress, in addition to the beneficial effects on the digestive system.3 In patients with IBS, certain probiotic strains reduce bloating and abdominal pain, alleviate general symptoms and improve the overall quality of life.10,11 The secret to success in the case of probiotics does not solely rely on their ability to reset the imbalance in the natural gut microbiota and play a non-invasive part in gut ecology.12 Rather, these live bacteria play a direct role in the affected microbiota-gut-brain axis, in effect not just targeting a single symptom, but a range of gastrointestinal, as well as psychological, symptoms.12 The implication of abnormal gut microbiota in the initiation of IBS is underscored by the fact that IBS presents itself in many patients following a bout of gastroenteritis – inflammation of the gut caused by bacteria that greatly disturb the natural gut microbiota.13,14 In the long run, probiotics have salubrious effects because they normalise gut microbiota, which in turn affects the health of the gut and, via the microbiota-gut-brain axis, the brain, thereby targeting a whole suite of symptoms.

In the light of the plethora of probiotic treatments on the market that all claim to rebalance gut microbiota, it is wise to remember that in the world of probiotics, as in the world of men, all strains are not equal.11 Some probiotic strains provide no relief of the symptoms of IBS, whilst others provide only mild relief to some patients.10,11 All in all, the multi-strain approach seems to be superior to treatment with single strains of bacteria, probably because they align with the natural diversity of the gut environment.15 In general, it is therefore prudent to use a probiotic in the treatment of IBS with proven clinical efficiency in a randomised, double-blind, placebo-controlled clinical trial.

In a recent study on 108 Iranian adults, one of the populations with the highest worldwide prevalence of IBS, 85% of the participants who received a multi-strain probiotic, Probio-Tec® Quatro-cap-4, reported relief of general symptoms after four weeks of treatment.16 In particular, there was a marked reduction in abdominal pain, bloating and rectal tenesmus in comparison to those participants who received the placebo.16 Some degree of relapse was seen in the symptoms ten weeks after discontinuation of the treatment, a reminder that even though probiotics can treat symptoms, a cure for IBS is yet to be found.16

The multi-strain probiotic, equivalent to QuatroFlora® in South Africa, investigated in this trial, combines four strains of beneficial bacteria, namely Bifidobacterium animalis subsp. lactis BB-12®, Lactobacillus acidophilus LA-5®, Lactobacillus delbrueckii subsp. bulgaricus LBY-27 and Streptococcus thermophilus STY-31, that colonise the small bowel and the colon. Together, these bacterial strains have a greater effect on abdominal symptoms when compared to the effect of each species acting alone.15 In conjunction, these bacteria contribute to a more normalised gut environment17 and suppress pathogenic bacterial growth18, both factors that might disturb the microbiota-gut-brain axis.12 Likewise, these bacteria support the immune system, which has been shown to be markedly affected in patients with IBS.19,20

There is no miracle cure for IBS. For that to be found, the real cause of IBS must be elucidated first. Nonetheless, for now, probiotic treatment is by far superior to other chemical drugs and is safe for long-term use. Probiotics not only rebalance the delicate environment of our guts, but also play into the microbiota-gut-brain axis so that the most unlikely of pairs can live in harmony.


  1. Bercik P, Denou E, Collins J, Jackson W, Lu J, Jury J, Deng Y, Blennerhassett P, Macri J, McCoy KD, Verdu EF, Collins SM. The intestinal microbiota affect central levels of brain-derived neurotropic factor and behavior in mice. Gastroenterology. 2011 Aug; 141(2): 599-609.
  2. Diaz Heijtz R, Wang S, Anuar F, Qian Y, Bjorkholm B, Samuelsson A, Hibberd ML, Forssberg H, Pettersson S. Normal gut microbiota modulates brain development and behavior. Proc Natl Acad Sci U S A. 2011 Feb; 108(7): 3047-52.
  3. Allen AP, Hutch W, Borre YE, Kennedy PJ, Temko A, Boylan G, Murphy E, Cryan JF, Dinan TG, Clarke G. Bifidobacterium longum 1714 as a translational psychobiotic: modulation of stress, electrophysiology and neurocognition in healthy volunteers. Transl Psychiatry. 2016 Nov; 6(11): e939.
  4. Canavan C, West J, Card T. The epidemiology of irritable bowel syndrome. Clin Epidemiol. 2014 Feb; 6: 71-80.
  5. Przekop P, Haviland MG, Zhao Y, Oda K, Morton KR, Fraser GE. Self-reported physical health, mental health, and comorbid diseases among women with irritable bowel syndrome, fibromyalgia, or both compared with healthy control respondents. J Am Osteopath Assoc. 2012 Nov; 112(11): 726-35.
  6. Kennedy PJ, Cryan JF, Quigley EMM, Dinan TG, Clarke G. A sustained hypothalamic– pituitary–adrenal axis response to acute psychosocial stress in irritable bowel syndrome. Psychol Med. 2014 Oct; 44(14): 3123-34.
  7. Kennedy PJ, Allen AP, O’Neill A, Quigley EM, Cryan JF, Dinan TG, Clarke G. Acute tryptophan depletion reduces kynurenine levels: implications for treatment of impaired visuospatial memory performance in irritable bowel syndrome. Psychopharmacology (Berl). 2015 Apr; 232(8): 1357-71.
  8. Kennedy PJ, Clarke G, O‘Neill A, Groeger JA, Quigley EMM, Shanahan F, Cryan JF, Dinan TG. Cognitive performance in irritable bowel syndrome: evidence of a stress-related impairment in visuospatial memory. Psychol Med. 2014 May; 44(7): 1553-66.
  9. Lacy BE, Weiser K, De Lee R. The treatment of irritable bowel syndrome. Ther Adv Gastroenterol. 2009 Jun; 2(4): 221-38.
  10. Didari T, Mozaffari S, Nikfar S, Abdollahi M. (2015). Effectiveness of probiotics in irritable bowel syndrome: updated systematic review with meta-analysis. World J Gastroenterol. 2015 Mar; 21(10): 3072-84.
  11. McKenzie YA, Thompson J, Gulia P, Lomer MCE. British Dietetic Association systematic review of irritable bowel syndrome in adults (2016 update). J Hum Nutr Diet. 2016 Oct; 29(5): 576-92.
  12. Jeffery IB, Quigley EM, Öhman L, Simrén M, O’Toole PW. The microbiota link to irritable bowel syndrome: an emerging story. Gut Microbes. 2012 Nov; 3(6): 572-6.
  13. Spiller R, Garsed K. Postinfectious irritable bowel syndrome. Gastroenterology. 2009 May;136(6): 1979-88.
  14. Thabane M, Marshall JK. Post-infectious irritable bowel syndrome. World J Gastroenterol. 2009 Aug; 15(29): 3591-6.
  15. Ortiz-Lucas M, Tobías A, Saz P, Sebastián JJ. Effects of probiotic species on irritable bowel syndrome symptoms: a bring up to date meta-analysis. Rev Esp Enferm Dig. 2013 Feb; 105(1): 19-36.
  16. Jafari E, Vahedi H, Merat S, Momtahen S, Riahi A. Therapeutic effects, tolerability and safety of a multi-strain probiotic in Iranian adults with irritable bowel syndrome and bloating. Arch Iran Med. 2014 Jul; 17(7): 466-70.
  17. Jiang T, Savaiano DA. Modification of colonic fermentation by bifidobacteria and pH in vitro. Impact on lactose metabolism, short-chain fatty acid, and lactate production. Dig Dis Sci. 1997 Nov; 42(11): 2370-7.
  18. Gareau MG, Sherman PM, Walker WA. Probiotics and the gut microbiota in intestinal health and disease. Nat Rev Gastroenterol Hepatol. 2010 Sept; 7(9): 503-14.
  19. Major G, Spiller R. Irritable bowel syndrome, inflammatory bowel disease and the microbiome. Curr Opin Endocrinol Diabetes Obes. 2014 Feb; 21(1): 15-21.
  20. Martínez C, González-Castro A, Vicario M, Santos J. Cellular and molecular basis of intestinal barrier dysfunction in the irritable bowel syndrome. Gut Liver. 2012 Jul; 6(3): 305-15.