EVALUATION OF THE PATHOGENESIS OF FLATULENCE AND ABDOMINAL CRAMPS IN PATIENTS WITH LACTOSE-MALABSORPTION

Aim of this study was to assess whether the interindividual difference s in the development of flatulence and cramps in patients with lactose malabsorption are due to the quantity of malabsorbed lactose or gas a ccumulation, or if accelerated intestinal transit or increased percept ion of gas might play a role. Hydrogen breath tests were performed in 43 patients with lactose malabsorption after ingestion of 50 g lactose and, on a separate day, 25 g lactulose. The unabsorbed amount of lact ose, small bowel transit time and colonic hydrogen accumulation were a ssessed in patients who did and did not develop flatulence and cramps after ingestion of lactose. The unabsorbed amount of lactose, small bo wel transit time and volume and rate of colonic hydrogen accumulation were the same in patients who did or did not have symptoms after lacto se. Patients with flatulence and cramps had a significantly longer tim e interval between the onset of the increase and peak breath hydrogen concentration (p < 0.05) and a significant correlation between the tim e of occurrence of peak symptoms and the time of peak breath hydrogen concentration (r = 0.75, p < 0.001). Our data suggest that subjective symptoms of lactose intolerance are not due to the amount of malabsorb ed lactose or to the volume or rate of gas accumulation per se, but ar e related to increased perception of gas.