Dietary fat quantity and composition induce changes in proliferation and membrane lipids in rat colon cells

We have previously observed changes in colon cell proliferation in growing rats fed different levels of dietary fat as beef tallow or corn oil. Here we measured cellular proliferation at 18 and 30 weeks in the colon of rats fed beef tallow or corn oil and treated with the chemical carcinogen azoxymethane. Additionally, we assessed colon cell membrane lipid composition after 18 weeks on the defined diets and tumor incidence at 30 weeks. Dietary fat type and quantity significantly affected colon cell proliferation. Membrane phospholipids and free fatty acids were significantly affected by fat type. Tumor incidence was not affected by diet type. We conclude that dietary fat induces changes in cell membrane lipid composition and proliferation in the colon and these changes may be related to the development of tumors.