Transplacental effects of a 15% olive-oil diet on chemically-induced tumorigenesis in offspring

We evaluated whether feeding pregnant female rats a diet high in olive-oil, that showed a tumor-preventive effect in adults, has a similar preventive effect on chemically-induced cancer in offspring (i.e, mammary glands and c olon cancer in rats). The control group was fed the same 7% corn-oil diet a s their mothers. Experimental group I was fed a 7% corn-oil diet while thei r mothers received a 15% olive-oil diet. Experimental group II was fed the same 15% olive-oil diet as their mothers. Female offspring were twice admin istered 7,12-dimethylbenz(a)antracene (DMBA) in doses of 10 mg/rat. Male of fspring were injected 6 times with 1,2-dimethylhydrazine (DMH) in doses of 20 mg/kg body weight. Effect of DMBA was manifested in a high rate of tumor igenesis: the number of tumor-bearing rats in control offspring reached 52. 0%. This effect increased to 60.6% among offspring of experimental group II and to 67.7% in offspring of experimental group I. The mean tumor size inc reased significantly in control offspring. Following administration of DMH number of tumor-bearing rats was similar in all groups of offspring: 36.7%, 40.7% and 42.8%. Tumor types differed: the majority of tumors in the contr ol group were benign polyps and adenomas (72.1%) and the number of adenocar cinomas was low (27.9%). The number of malignant tumors increased to 37.5% in offspring of experimental group II and to 45.5% in offspring of experime ntal group I, In control group offspring, a distinct tendency to increased body weight and a significant increase in spleen weight were seen. The find ings indicate that feeding mothers a diet high in fat concentrations, even those with known tumor preventive significance in adults, lose this cancer- inhibiting role in offspring.