Replacing corn oil with canola oil may lower cancer risk not only for women, but for their unborn babies, US researchers reported.
They found that mice fed canola oil while pregnant were less likely to develop breast cancer-- and so were their unborn pups - than mice fed corn oil.
The findings are likely because of omega 6 fatty acids, the researchers told a meeting of the American Association for Cancer Research. Some research has linked high amounts of omega-6 fatty acids to health problems including cancer.
Fifty percent of the fatty acids in corn oil are omega 6, while just 20 percent of the fatty acids in canola oil are. And canola oil is much richer than corn oil in omega 3 fatty acids, which are linked with heart and cancer benefits.
Elaine Hardman and colleagues at the Marshall University School of Medicine in West Virginia tested genetically engineered mice that develop cancer early in life.
Those fed a canola-rich diet were slower to develop cancer than those fed corn oil, and so were their pups.
"By seeing a delay in their cancer development, we can hope that translates into a delay in cancer development in humans, too," Hardman said in a telephone interview.
Hardman's team also examined the mice for genetic changes associated with cancer, and found for example that CEBP alpha, a so-called transcription factor involved in breast cancer differentiation, and Egr1, a tumour suppressor gene, were overly active in the mice fed corn oil and less active in those fed canola.
And the same was true of their pups.
"The only explanation is that during gestation and lactation, the mother's diet must be imprinting the genes of the baby," Hardman said.
While research continues, Hardman said it would be easy for people to switch to canola oil.
"The bottom line message to people is this is a dietary change that would be very easy to make. It doesn't cost any money and it might help prevent cancer in the future," she said. "At worst it won't do any harm."
Fish, leafy green vegetables, some nuts and canola oil are rich in omega 3 fatty acids while omega 6 fats are found in corn or soybean products and in the meat from animals fed them, including cattle, pigs and chicken.
"Americans now eat a high percentage of omega 6 fats," Hardman said in a statement. She believes cancer rates may be linked to diets high in these fats.