In vitro and in vivo lactose and lactulose effects on colonic fermentation and portal-systemic encephalopathy parameters.

Lactose intolerance occurs in the majority of human groups, excluding people from Northern Europe. Because its effect is similar to that of lactulose, lactose seems to be an alternative treatment for patients with portal-systemic encephalopathy (PSE) and lactase deficiency. The mechanism of action of lactose is similar to that of lactulose. In vivo, lactose improves PSE parameters and causes acidic diarrhea. We performed in vitro studies in a fecal incubation system to investigate the biochemical and bacteriological effects induced by different substances customarily used for the treatment of patients with PSE (lactose, lactulose and Neomycin). In vitro experiments showed that lactose and lactulose decreased aerobic flora counts and reduced the pH of fecal incubation. Both disaccharides reduced the ammonia concentration in the incubation system.