Dietary fat and antioxidant status relating to colon carcinogenesis
MetadataShow full item record
Epidemiological evidence has linked dietary fat with colorectal cancer in humans but with mixed results. Studies using animal models have shown that high fat diets containing predominantly corn oil, beef tallow or lard induce colon tumorigenesis to a greater extent than corresponding low fat diets; however, these findings are still inconclusive. Recently, some research indicated differences according to the types of fat used and support the concept that diets high in unsaturated fatty acids have a greater tumor-promoting capability than diets high in saturated fatty acids. The mechanism was proposed that free radicals were involved in colon carcinogenesis. Therefore, a polyunsaturated fatty acid (PUFA) diet would increase antioxidant activity to prevent free radical damage. Several studies have indicated that dietary lipids influence the liver microsomal mixed function oxidase system. It has been reported that the elevation of dietary polyunsaturated fatty acid intake increases the activity of the liver microsomal enzymes responsible for carcinogen metabolism. Some studies directed the diet-related effect on the susceptibility of colonic cells to nuclear-damaging agents. However, there have been very few studies on the effects of dietary fat and nuclear aberrations due to xenobiotics challenge. The purpose of this study was to examine the effect of amount and type of dietary fat on the (1) colon mucosal antioxidant status; (2) liver microsomal demethylase activity; (3) liver microsomal and cytosolic mutagenic activation; and (4) colonic epithelial nuclear aberrations during colon carcinogenesis.