Effect of high fat and nutrient depleted diets on colon tumor formation in mice.
Abstract
We investigated the effect of high fat and nutrient depleted diets on the
formation of colon tumors in female Swiss mice treated with 1,2-
dimethylhydrazine (DMH). Mice received the following diets: control diet
(laboratory chow, 5.5% fat) or chow with added starch and/or corn oil so as
to supply a fat level of 5.5% (diet F6) or 23% (diet F23), while reducing the
level of nutrients and dietary fiber per. 100 calories to 61% of the level of
the control diet. DMH was given as 5 weekly s.c. injections. Diets were
given variously from 6 weeks before the first injection until 7 days after the
last one (initiation period) or else for the subsequent 22 weeks until sacrifice
of the mice (promotion period). A high fat diet (diet F23 vs. F6) tended to
increase adenoma formation when fed during the initiation period but this
requires further study. Feeding it in the promotion period increased the
incidence of adenocarcinomas. A nutrient depleted diet (diet F6 vs. the
control diet) caused a decreased incidence of adenocarcinomas.