Fecal fat excretion in irritable bowel syndrome.

Irritable bowel syndrome (IBS) is considered as a diagnosis of exclusion. However, assessment of fecal fat excretion, being a cumbersome procedure, is seldom performed in the investigation of such patients [1]. In two recent studies published in Scandinavian Journal of Gastroenterology, the authors measured fecal fat excretion in two IBS populations, one with post-infectious IBS (PI-IBS) [2] and one with perceived food hypersensitivity (FH-IBS) [3]. Here the authors summarize and comment on their experience. IBS was diagnosed according to the Rome criteria. The PI-IBS group consisted of 23 patients with IBS following previously cured infection with Giardia lamblia, while the FH-IBS group consisted of 75 patients with unexplained, self-reported food hypersensitivity. Controls were 20 healthy students without IBS. While on their customary diets, patients and controls collected all feces for 3 days, and fat content of homogenized pooled feces was analyzed by a modified titration method as described previously [4]. The results are presented in Figure 1. Patients with IBS excreted significantly more fat than healthy controls (ANOVA, p = 0.01, Figure 1A). The difference between the PI-IBS and FH-IBS groups was not significant (p = 0.06). Consistent with prior results, fecal fat excretion was <7 g fat per day in the healthy controls. However, 10 (43%) of 23 PI-IBS patients and 19 (25%) of 75 FH-IBS patients excreted more than 7 g fat per day. Fecal fat excretion was unrelated to phenotype (diarrhea, constipation or