Influence of dietary fat on fecal mutagenicity in premenopausal women

Abstract

A dietary intervention study was conducted on 31 premenopausal women (age: 20-40 years) to investigate the relationship between dietary fat and fecal mutagenicity. After a free-living period (baseline) of one menstrual cycle, the subjects were placed on a high-fat diet (40% calories from fat) for 4 menstrual cycles, followed by a low-fat diet (20% calories from fat) for 4 menstrual cycles. One-half of the subjects were randomly assigned throughout the study to a diet with a P:S ratio of 1.0 while the other half was assigned to one with a P:S ratio of 0.3; body weight by group remained constant. Three-day stool samples were collected at the mid-follicular period during the free-living phase and during the 4th menstrual cycle of each of the 2 controlled diet periods. Mutagenicity was assayed by the SOS chromotest. Reduction of dietary fat was accompanied by a significant decrease in fecal mutagenicity in both P:S groups. Combined values, i.e., both P:S groups, were 20.3 units for high-fat diets vs. 8.78 for low-fat diets.

Food consumption and cancer of the colon and rectum in north‐eastern Italy

“…Plausible mechanisms to explain the causative role of dietary fat include the effect of oxidized fat and the elevated production of bile acids, fecal mutagens and ketosteroids (Hill et al, 1971;Cheah, 1990). Dietary fiber also influences the production of free bile acids in several ways (e.g., modification of intestinal bacterial products, increase in fecal transit or fecal bulk, absorption or inactivation of bile acids) (Cheah, 1990;Nair et aL, 1990;Newmark and Lupton, 1990). From the present data, however, it is not possible to discriminate between the effect attributable to the fibrous component of vegetables and the effect attributable to other constituents (Trock et al, 1990).…”

Epidemiology and Mechanisms Relating Diet to Risk of Colorectal Cancer

“…Fat, bile acids, p H High fat diets increase faecal mutagenicity in humans (Nair et al 1990) and lead to increased levels of bile acids in the colonic lumen (Cummings et al 1978). The secondary bile acid deoxycholic acid is known to be damaging to the mucosa and a promoter of bowel cancer in rodent systems (Narisawa et al 1974).…”