Maternal Diet and Risk of Cancer in Offspring

Abstract

Researchers at Georgetown University's Lombardi Cancer Center have found that pregnant rats (dams) fed a diet rich in whole wheat produced female pups that were at a substantially reducedrisk of developing breast cancer, compared to rats fed other grains or no grain. Their study adds to a growing body of evidence that maternal diet can affect future disease risk in the offspring.

The study, published in the November 15 issue of the International Journal of Cancer, found that the whole wheat diet in the rat dams increased expression of a number of different genes known to protect against cancer risk in their female pups, so that when the young rats were exposed to a carcinogen, they were less likely to develop breast cancer.

Those genes include ones known to reduce a human's risk for developing cancer, including BRCA1 (linked to breast and ovarian cancer) and p53 (linked to many cancers), said the study's leadauthor, Leena Hilakivi-Clarke, Ph.D., a professor of Oncology. Additionally, the offspring had lower levels of DNA adducts in their blood, suggesting an improved ability to repair damage that occurredto their DNA, a process also important to human cancer prevention.

"This does not mean that pregnant women who eat lots of whole wheat will absolutely protect their baby girls against future breast cancer development ? that is much too far a leap to make based on a study in rats," said Hilakivi-Clarke.

"But we also know from other studies that human fetal nutrition can help determine who will be at later risk for heart disease, hypertension, and diabetes, so we have confidence that our experimental model system is generating data that can be relevant to humans," she said.

"In any case, I don't know of any evidence that eating whole wheat is bad for any human, and this evidence suggests that it just might be good for pregnant women," she said.

The researchers speculate that whole wheat provides protection against development of breast cancer because it contains phytic acid, which possess strong antioxidant properties. Molecules that cause oxidative stress are unstable and can damage cells, setting up conditions that promote cancer development. Some studies have suggested that phytic acids can reduce colon cancer risk.

The researchers chose rats to study because the breast cancer that develops in these animals closely mimics the estrogen-positive cancer that occurs in 70 percent of humans. They fed four groups of pregnant dams a different diet consisting of 6 percent fiber, either from whole wheat, oat, defatted flax seed, or, in the control group, cellulose. "The only difference among the groups was the source of the fiber," Hilakivi-Clarke said. Two months after the pups were born, gene expression was measured in their mammary glands, and then the rats were given a carcinogen to induce breast cancer.

The researchers monitored the percentage of pups that developed breast cancer in each group, and how quickly the cancer appeared and progressed. They then compared the groups, and found that dams fed whole wheat had significantly fewer tumors. The oat diet group and the control group had about the same amount of cancer development, and the pups fed flaxseed had the most breast cancer.

Hilakivi-Clarke said that in the developing fetus, the whole wheat diet may be turning on and off genes that could permanently alter biological programming, priming a sustained and strong response against cancer development.

"How this happens is yet to be determined, but it likely involves changes that reduce the potential number of targets by which breast cancer could develop," she said. Researchers also do not know why defatted flax seed would increase cancer risk, Hilakivi-Clarke said. "There is great potential in these kinds of studies, and we feel confident that our model system will provide data that could beapplicable to humans," she said.

About Lombardi Comprehensive Cancer Center

The Lombardi Comprehensive Cancer Center, part of Georgetown University Medical Center and Georgetown University Hospital, seeks to improve the diagnosis, treatment, and prevention of cancer through innovative basic and clinical research, patient care, community education and outreach, and the training of cancer specialists of the future. Lombardi is one of only 39 comprehensive cancer centers in the nation, as designated by the National Cancer Institute, and the only one in the Washington, DC, area. For more information, go to http://lombardi.georgetown.edu.

For more informatin, contact: Laura Cavender; Tel.: [phone]; Email: [email protected]