Abstract
The subchronic oral toxicity of lactitol was examined by feeding the test substance at dietary levels of 0, 5, 10, and 15% to groups of 6 male and 6 female dogs for 26 weeks. A comparison group received a diet containing 15% lactose. Although the dogs gradually were adapted to the high doses of the test compounds, diarrhea was observed in the dogs fed 10 and 15% lactitol, and 15% lactose. The diarrhea in the lactose group was less severe than in the 10% lactitol group. Body weight did not show treatment-related differences between the groups. Food intake was slightly higher in the lactitol groups than in the controls. Hemoglobin content (Hb), packed cell volume (PCV), and red blood cell counts (RBC) were slightly lower in dogs of the 15% lactitol group and the 15% lactose group. No other hematological parameters exhibited differences between the various treatment groups. Plasma glutamic-oxalacetic transaminase (GOT), glutamic-pyruvic transaminase (GPT), protein, albumin, glucose, and urea showed no treatment-related differences. However, plasma alkaline phosphatase (AP) tended to be lower in the females of all lactitol groups from day 0 to the end of the study. Transient decreases in plasma calcium and potassium levels were seen in lactitol- and lactose-fed female dogs. Semiquantitative urine analysis did not reveal any abnormalities. There was no impairment of the function of the liver or kidneys in any of the groups. The absolute and relative weights of the cecum, filled as well as empty, were relatively high in males of all lactitol groups and in females of the 10 and 15% dose groups. The weight of the colon and the small intestines, which were determined in males only, were increased in the 5 and 15% lactitol groups. Gross and microscopic examination did not reveal any pathological change that could be attributed to the feeding of lactitol or lactose. It is concluded that under the conditions of the study, daily doses of up to 4.2–6.8 g/kg b.w. are tolerated without obvious signs of toxicity.