Incidence and significance of faecal hydroxystearic acid in alimentary disease

Three-day faecal collections were obtained from 87 patients with a variety of gastroenterological diagnoses and 12 control subjects while consuming normal diets. Faecal weight, total fatty acids, and the proportion of hydroxystearic (OHSA) acid were measured. All patients had some easily detectable hydroxystearic acid. It was found that in general the percentage of OHSA in the faecal fatty acids increased with increasing fat output. Thus most patients excreting less than 20 g of fat per day had less than 5% OHSA while those with greater steatorrhoea had levels of 6 to 23%. Exceptions were patients with mild steatorrhoea with ileal disease, ileal resections, or small intestinal bacterial colonization, who had more than 5% OHSA whilst patients with colonic resection had much lower levels of OHSA than otherwise found. It is impossible to determine whether OHSA had a specific cathartic action from this study since the data implicated total fatty acids to the same extent.