Compared to healthy controls, IBS patients developed more symptoms and had an abnormal accumulation of fluid in the small bowel in response to ingestion of the unabsorbable carbohydrate lactulose. This may be due to impaired motor activity of the small intestine or impaired function of the ileocecal segment.

Objective.Patients with perceived food hypersensitivity typically present with multiple health complaints. We aimed to assess the severity of their intestinal and extra-intestinal symptoms.Materials and methods.In a prospective study, 84 patients referred to our outpatient clinic for investigation of perceived food hypersensitivity were enrolled consecutively. Irritable bowel syndrome (IBS) was diagnosed according to the Rome III criteria. Severity and impact of bowel symptoms, fatigue and musculoskeletal pain were evaluated by using the following questionnaires: The IBS Severity Scoring System (IBS-SSS), the Fatigue Impact Scale (FIS), the FibroFatigue Scale (FFS), and visual analogue scales (VAS) for scoring of musculoskeletal pain.Results.All but one patient were diagnosed with IBS, 58% with severe symptoms. Extra-intestinal symptoms suggestive of chronic fatigue and fibromyalgia were demonstrated in 85% and 71%, respectively. Neither IgE-mediated food allergy nor organic pathology could explain the patients' symptoms. Nevertheless, malabsorption of fat was demonstrated in 10 of 38 subjects.Conclusions.Perceived food hypersensitivity may be associated with severe, debilitating illness. The comorbid triad of IBS, chronic fatigue, and musculoskeletal pain is striking and may point to a common underlying cause.

Irritable bowel syndrome (IBS) is often accompanied by extra-intestinal symptoms, including fatigue and musculoskeletal pain. The present study aimed to investigate whether these symptoms were associated with markers of enterocyte disintegrity, endotoxemia and inflammation. Patients with IBS were recruited consecutively from our outpatient clinic (n=94) and compared with a group of healthy controls (n=20). Habitual symptoms were assessed using the IBS Severity Scoring System, the Fatigue Impact Scale and Visual Analogue Scales for measuring musculoskeletal pain. A lactulose challenge test was performed to induce post-prandial symptoms, and blood samples were obtained prior to and 90 min following lactulose ingestion to determine levels of intestinal fatty acid binding protein (iFABP), lipopolysaccharide (LPS), the LPS co-receptor soluble cluster of differentiation (sCD) 14, monocyte chemoattractant protein-1 (MCP-1) and calprotectin. Habitual symptom scores were high among the included patients, and lactulose ingestion induced significantly more symptoms in the patient group compared with the healthy control group (P=0.0001). Serum levels of iFABP were reduced in IBS patients compared with healthy controls, prior to and following lactulose ingestion (P=0.0002 and P=0.0001, respectively). Following lactulose ingestion, iFABP levels decreased in IBS patients (P=0.0001) and in healthy controls (P=0.02). Fasting levels of LPS, sCD14, MCP-1 and calprotectin were not significantly different between IBS patients and healthy controls. However, following lactulose ingestion, LPS levels increased in healthy controls (P=0.03), whereas MCP-1 levels decreased in IBS patients (P=0.008). Intestinal and extra-intestinal symptom severities were not correlated with levels of circulating biomarkers. No assessed biomarker in the present study appeared to be associated with symptom development in IBS patients. However, the implications of the low levels of iFABP observed require further investigation.

BackgroundIngestion of low-digestible carbohydrates triggers symptoms in patients with irritable bowel syndrome (IBS). These carbohydrates become substrates for microbial fermentation in the colon, yielding short-chain fatty acids (SCFAs) that are readily absorbed. Aiming to compare colonic fermentation in patients with IBS and healthy controls, we analyzed the concentrations of SCFA in serum at fasting and 90 minutes following ingestion of an unabsorbable, but fermentable carbohydrate, lactulose.MethodsPatients with IBS according to Rome III criteria (n=22) and healthy controls (n=20) ingested 10 g lactulose dissolved in water. Symptoms were graded by questionnaires and SCFA were analyzed using hollow fiber-supported liquid membrane extraction coupled with gas chromatography.ResultsLactulose induced more symptoms in patients with IBS than in healthy controls (P=0.0001). Fasting serum levels of SCFA did not differ between patients with IBS and controls. However, the postprandial levels of total SCFA (P=0.0002), acetic acid (P=0.005), propionic acid (P=0.0001), and butyric acid (P=0.01) were significantly lower in patients with IBS compared with healthy controls. There was no correlation between the levels of serum SCFA and symptom severity.ConclusionLow-serum levels of SCFA after lactulose ingestion may indicate impaired colonic fermentation in patients with IBS. Conceivably, this disturbance is related to symptom generation, but the mechanism is not clear.

No abstract