Condition: Prikkelbaredarmsyndroom

Black en collega's poolden gerandomiseerde onderzoeken naar dieetinterventies bij PDS. Het low-FODMAP-dieet kwam bovenaan voor zowel algehele symptomen als buikpijn, vóór standaard dieetadvies en andere eliminatiebenaderingen. De onderzoeken waren klein, moeilijk te blinderen (mensen kunnen merken wat ze eten), en de algehele zekerheid werd als laag beoordeeld. Het dieet is een instrument in drie fasen, geen manier van eten voor het leven: een strikte beperking van enkele weken, dan een gestructureerde herintroductie om persoonlijke triggers te vinden, dan het minst beperkende langetermijndieet. Onbeperkt in de strikte fase blijven, versmalt het dieet en kan gunstige darmbacteriën uithongeren, wat waarom het met een diëtist wordt gedaan.

Moayyedi and colleagues separated fiber by type. Soluble fiber (psyllium, ispaghula husk) lowered the relative risk of persistent symptoms to roughly 0.83, a number needed to treat of about 7. Insoluble fiber (bran) showed no benefit over placebo. The practical read is to add soluble fiber slowly, since starting at a full dose can itself cause bloating and wind for the first week or two before symptoms settle.

Pooled trials that separated insoluble bran from soluble fiber found bran no better than placebo for global symptoms (relative risk 1.02, 95% CI 0.82 to 1.27), and the review found no evidence of harm. This is one reason blanket high-fiber advice can fall flat in IBS. The lever is the type of fiber, not the amount.

Peppermint oil relaxes intestinal smooth muscle by blocking calcium channels. Meta-analyzes of enteric-coated preparations find a consistent benefit for global symptoms and abdominal pain over placebo, one of the better numbers-needed-to-treat among IBS therapies. The common side effect is reflux and heartburn, which the enteric coating (designed to release lower in the gut) reduces but does not remove. It is among the first things guidelines suggest trying because it is inexpensive and low-risk.

Ford and colleagues pooled randomized trials of antispasmodics in IBS. Agents such as otilonium, hyoscine, and mebeverine improved abdominal pain and global symptoms over placebo, with a favorable side-effect profile at the pooled level, though individual drugs differ and some carry anticholinergic effects such as dry mouth. They suit cramp-predominant symptoms and can be taken on demand around meals.

Gut-directed hypnotherapy is a standardized course, commonly seven to twelve sessions, that uses focused relaxation and suggestion aimed at normalizing gut sensation and function. Schaefert and colleagues found it superior to control conditions for symptom improvement, with durability in follow-up. It works on the gut-brain axis, not on diet or motility directly, which is why it can help when dietary changes have not. Access is the main limitation: trained practitioners are scarce, though app-delivered programs are being studied.

Black and colleagues ranked psychological therapies in a network meta-analysis. CBT (including gut-focused and internet-delivered forms) and gut-directed hypnotherapy came out among the most efficacious for global IBS symptoms versus control. These therapies act on the gut-brain axis, the two-way signaling between the digestive tract and the nervous system, and their benefit is evidence that this axis is a real treatment target, not that the disorder is psychological in origin. Trials are hard to blind and dropout is common, so effect sizes carry uncertainty.

ATLANTIS randomized 463 adults with IBS in UK general practice to titrated low-dose amitriptyline (10 to 30 mg) or placebo as a second-line treatment. The amitriptyline group had a clinically meaningful improvement in the IBS severity scoring system, about 27 points lower than placebo at 6 months, and were more likely to report overall relief. At these doses the drug acts as a gut-brain neuromodulator, damping visceral pain signaling and slowing transit, which also makes it better suited to the diarrhea-predominant pattern. Anticholinergic effects such as dry mouth and drowsiness are common; the trial let patients self-adjust the dose to manage them.

Rifaximin is a poorly absorbed antibiotic that acts on gut bacteria without much of it reaching the rest of the body. Menees and colleagues pooled 5 randomized trials and found it more effective than placebo for global IBS symptoms (odds ratio 1.57, 95% CI 1.22 to 2.01) and for bloating (odds ratio 1.55, 95% CI 1.23 to 1.96), with a number needed to treat around 10 for each and adverse effects no higher than placebo. The two phase 3 TARGET trials tested 550 mg three times daily for two weeks in non-constipation IBS and found global symptom relief in 40.7% on rifaximin against 31.7% on placebo. It is licensed for the diarrhea-predominant and mixed subtypes, not for constipation. The benefit is modest and symptoms commonly relapse, so a clinician weighs it as a prescription option, and repeat courses against the general case for antibiotic restraint, not as a first move.

Ford and colleagues pooled probiotic, prebiotic and synbiotic trials in IBS. The combined estimate favored probiotics for global symptoms, but between-study heterogeneity was substantial, the products and strains varied widely, and the evidence could not identify which species, strain or dose was responsible. That is why a general probiotic sold as an IBS cure over-promises: the category effect is small and inconsistent, and the benefit, where it exists, is strain-specific. A reasonable approach is a single product for around four weeks and stopping if nothing changes.

Johannesson and colleagues randomized 102 adults with IBS to a physical-activity intervention or usual care over 12 weeks. The active group improved on the IBS severity scoring system, and significantly fewer of them worsened. Exercise plausibly helps through faster transit, reduced stress arousal and effects on the gut-brain axis. The trial was small and unblinded, so this sits as an encouraging early finding, and the intervention is cheap and broadly beneficial.

Klem and colleagues pooled cohort studies following people after acute enteric infection. The prevalence of new IBS afterwards was about 10%, and the risk of IBS was roughly fourfold higher than in uninfected comparators, with risk still elevated years later. Bacterial infection, more severe illness and psychological stress at the time raised the risk. Post-infectious IBS gives a concrete, non-psychological origin for a large subgroup and points to low-grade immune activation and altered gut nerves and microbiota as mechanisms.

The Rome IV framework reclassified IBS and related conditions as disorders of gut-brain interaction. The recognized mechanisms include altered motility, visceral hypersensitivity (the gut registering normal events as painful), low-grade mucosal immune activation, shifts in the gut microbiome, changes in intestinal permeability, and altered central processing of visceral signals. This reframing replaces the older idea of a purely functional or psychosomatic complaint. The gut-brain axis runs both ways, so psychological stress does modulate symptoms, but the physiological changes are measurable and the disorder is not imagined.

IgG antibodies to foods are a normal marker of dietary exposure and tolerance, not of intolerance, so a panel of positive foods does not identify triggers. The American College of Gastroenterology guideline recommends against IgG food-antibody testing to guide the diet in IBS. The most-cited supporting study, an RCT of IgG-guided elimination, reported a symptom benefit but was hampered by imperfect blinding and a modest between-group difference, and it has not been reliably reproduced. A structured elimination and reintroduction, done with guidance, is the sounder way to find your dietary triggers.

A systematic review and meta-analysis found biopsy-confirmed celiac disease more common among people with IBS symptoms across all IBS subtypes than in comparison groups, with a pooled odds ratio of 4.48. The excess was not seen in North American studies. Because celiac disease is treatable and its untreated course carries serious harm, guidelines recommend serologic testing (such as tissue transglutaminase antibodies) as part of the diagnostic work-up. This is one of the concrete reasons an IBS diagnosis is reached after excluding specific conditions.