[The effect of lactitol on the production of expired hydrogen in normal subjects].

In man, unabsorbed disaccharide lactitol is fermented by colonic flora with an H2 breath production proportional to the absorbed quantity. The osmolality of the ingested solution is without effect either on the oro-cecal transit time and the time of H2 peak, or on the output and peak value of H2 expired. The intestinal symptoms seemed less prominent with slighter osmolality. The beginning of H2 production and the amount of H2 recorded varied widely between different subjects and in the same subject. It is thus important to consider this variability when measuring transit time and evaluating the amount of unabsorbed sugar. The comparison between two analogous doses of lactitol and lactulose (Duphalac) shows lower H2 production with lactulose, but clinical symptoms are slightly more pronounced. The glycemic peak was significantly higher for lactulose than for lactitol.