As suggested by rodent studies and studies using human
breast cancer cells, dietary
canola oil is linked with lower
breast cancer risk. Here, we investigated the effect of maternal (pregnancy plus lactation) dietary
canola oil on the susceptibility of female Sprague-Dawley rat offspring to mammary
carcinogenesis. Although the control diet had 10%
soybean oil, the treatment diet was formulated to contain 10%
canola oil as a fat source. N-nitroso-N-
methylurea was injected to induce
mammary cancer in offspring. The offspring of canola-fed dams showed significantly decreased
tumor multiplicity (1.0 ± 0.3 vs. 1.9 ± 0.3, respectively; P = 0.04) and
tumor volume (1232.5 ± 771.0 mm(3) vs. 6,302.5 ± 1,747.4 mm(3), respectively; P = 0.01), along with increased survival rate (87% vs. 47%, respectively; P = 0.01). In addition, the
mRNA expression of development-related
gamma-glutamyltransferase 1 was significantly higher in the lactating mammary tissues of the canola group dams and mammary
tumor tissues of the offspring [2.5 ± 0.6 vs. 0.5 ± 0.2, respectively (P = 0.01) and 0.98 ± 0.03 vs. 0.56 ± 0.15, respectively (P = 0.05)]. These results suggest a potential anticancer effect of maternal dietary
canola oil and may be useful in devising prenatal nutritional strategies to reduce
breast cancer risk in humans.