Characterization and potential effects of manipulated intestinal microflora and diet in irritable bowel syndrome patients: preliminary study

Background and aim: Pathophysiology of Irritable Bowel Syndrome (IBS) includes psychosocial factors, visceral sensitivity and gut motility: their potential interplay seems to be influenced by exogenous and endogenous factors, as foods and gut flora. To characterize in IBS patients (pts) the potential role of Adverse Reactions to Foods (ARF) and the changes of gut flora induced by treatments by means of functional tests and faecal marker (SCFA, short-chain fatty acids); to evaluate if SCFAs concentrations were related to particular clinical features of IBS pts. Material and methods: 36 IBS pts presented diarrhoea (n.14;39%), abdominal pain (n.12;33%) and constipation (n.1O;28%). Pts were randomized to 2 main groups: 1)"flora"(n.20) with treatments aimed to modify gut flora (probiotic, antibiotic, fiber); 2)"other"(n.1O) with "classical" treatments (diet, antispasmodics). At baseline and at the end of treatment period, SCFAs concentrations, symptom scores and psychological assessment were determined. In all pts Lactose Breath Test (LB1) was performed; if positive, Glucose BT (GB1) was carried out. Findings were analyzed using Pearson correlation, Student t-test and paired t-test (p significant if value <0.05). Results: At baseline, concentrations of single and total SCFAs were found extremely variable without any relation to symptoms nor food intolerances. Pre vs post treatment SCFAs concentrations did not significantly change inside "flora" nor "other" groups. Anxiety disorders and mood alterations were found in 18 (67%) and 12 of27 pts (44.5%). Pre vs post treatment psychological scores did not significantly change, but symptoms scores improved inside each group ("flora" 1O.6±4.8 vs 7.47±4.4, p=O.OOI; "other" 10±4.8 vs 5.5±3.7, p=0.019). Milk Intolerance (MI) were reported by 24 of 34 pts (71 %); LBT was positive in 21 of 34 (62%): the consistency between reported and confirmed MI was low (19 of 34,56%).GBT was negative in all of 21 positive LBT. Conclusions: Actually, in these pts, measurement of faecal SCFAs is a not reliable marker for characterization of gut flora because of wide interindividual variability. Any treatment seems not to infl uence the psychological state, but improves abdominal symptoms. Screening for MI could be considered because of symptoms improvement by exclusion diet and pts' poor ability to identify offending foods.