Effect of short-term dietary fat on cell growth in rat gastrointestinal mucosa and pancreas.

The effects of high fat diets on gastrointestinal and pancreatic cell growth were examined in order to determine whether short-term high fat consumption leads to pancreatic and colonic cell hyperplasia. Three groups of eight rats were fed defined diets for 4 wk. The controls were fed a 5% corn oil diet (unsaturated fat) while those fed high fat diets received either 27% lard (saturated fat) plus 3% corn oil or 30% corn oil. Body weight gain and total caloric intakes were equal. Both high fat diets produced significant decreases in proximal jejunal mass (p less than 0.05), while in the distal ileum and cecum, the only change was the development of mucosal cell hypoplasia in the group fed the high unsaturated fat diet (p less than 0.05). The high fat diets produced no change in cell growth or the incorporation of [3H]thymidine into DNA of stomach, pancreas, or colon but did result in a higher level of pancreatic lipase and lower levels of amylase activity. These results show that a short-term high fat intake leads to small intestinal hypoplasia without affecting pancreatic or colonic cell growth and therefore do not support the hypothesis that dietary fat promotes pancreatic and colonic carcinogenesis by producing cell hyperplasia.