title: Net energy effects of dietary fat on chemically induced mammary carcinogenesis in F344 rats.
abstract: The effect of net energy, as distinct from kilocalorie intake or the percent of fat in the diet, on 7,12-dimethylbenz[a]anthracene [(DMBA) CAS: 57-97-6]-induced mammary tumorigenesis in female inbred F344 rats was investigated. Rats were fed a 5% corn oil diet from weaning until DMBA administration, when they were switched to one of three dietary regimens: 5% corn oil diet, low-fat diet fed ad libitum (LF); 30% corn oil diet, high-fat diet fed ad libitum (HF); or 30% corn oil diet fed at a level providing a calculated net energy equivalent to the group on LF [high-fat diet fed at a restricted level (HF-R)]. Calculated relative net energy values of the amounts of diet actually consumed by the groups on HF-R, LF, and HF were, respectively, 0.90, 1.00, and 1.07 (kcal equivalent to 34.1, 42.2, and 40.8, respectively). Weight gain for the groups on LF and HF-R was the same throughout the experiment (24 wk), while rats on HF weighed significantly more at 6 weeks and thereafter. Body composition analyses at 24 weeks established that the groups on HF and HF-R were equivalent in fat: protein ratio, whereas the group on LF had about 35% less body fat and 15% more body protein. Carcass energy was in the following order for rats in these diet groups: HF greater than HF-R greater than LF. At 24 weeks, tumor incidences for the groups on HF, LF, and HF-R were, respectively, 73, 43, and 7%. These data indicated that tumor appearance does not depend on the percent fat in the diet per se but rather on a complex interaction involving energy intake, energy retention, and body size.
authors.forename: G A
authors.initials: GA
authors.lastname: Boissonneault
authors.forename: C E
authors.initials: CE
authors.lastname: Elson
authors.forename: M W
authors.initials: MW
authors.lastname: Pariza
mesh_terms: D015127:9,10-Dimethyl-1,2-benzanthracene; D000818:Animals; D001823:Body Composition; D001835:Body Weight; D003043:Cocarcinogenesis; D004041:Dietary Fats / Q000378:metabolism* / Q000494:pharmacology; D002149:Energy Intake; D004734:Energy Metabolism; D005260:Female; D008325:Mammary Neoplasms, Experimental / Q000139:chemically induced* / Q000378:metabolism; D051381:Rats; D011916:Rats, Inbred F344; D013997:Time Factors
chemical_list: D004041:Dietary Fats; D015127:9,10-Dimethyl-1,2-benzanthracene