Mom-to-Be's Diet Protects
Daughters From Breast Cancer

Women who eat fish and nuts during pregnancy may protect their daughters against breast cancer years down the road. Eating these foods during childhood also helps.

Mothers who choose foods packed with omega-3 fatty acids during pregnancy and while nursing and then feed their kids such a diet after weaning may reduce the risk of breast cancer in their daughters by nearly 90%, early research in mice indicates.

"Just two servings of fish per week "Just two servings of fish per week and a daily fish oil supplement would be a good start for most pregnant women," says researcher W. Elaine Hardman, PhD, an assistant professor in the division of functional foods at Louisiana State University's Pennington Biomedical Research Center in Baton Rogue.

On the flip side, moms-to-be who eat a typical Western diet may be placing their children at risk of breast cancer, she says. That's because our diet is loaded with foods rich in omega-6 fatty acids -- meat, eggs, baked goods, breads, and most vegetable oils, she says.

But women whose moms have told them they ate all the junk food in sight during their pregnancy shouldn't panic. Feeding female baby mice a diet rich in omega-3 fatty acids after weaning reduced their risk of breast cancer by 40% -- even when moms ate a typical Western-style diet.

"This tells us that even if a mom doesn't consume the best diet for cancer prevention, her daughter can make up for it by consuming a diet rich in omega-3 fatty acids herself," Hardman tells WebMD. "It's never too late to switch."

The research adds to growing evidence that what a mother eats during pregnancy and while nursing affects the health of her children years down the road, says William Nelson, MD, PhD, professor of oncology at Johns Hopkins University School of Medicine in Baltimore.

The study was presented at the annual meeting of the American Association for Cancer Research.

Both omega-6 and omega-3 fatty acids are essential for good health. But in Western diets, the amount of omega-6 fatty acids is much greater than omega-3 fatty acids -- exactly the opposite of what it should be for good health, according to Hardman.

The ratio to shoot for, experts say, is roughly four times as much omega-3s as omega-6s. But the typical American diet has it totally backward -- 20 times as much omega-6s -- and that spells trouble.

Omega-3 fatty acids are found in fish, especially cold water fish such as tuna, salmon, and mackerel, as well as in canola and flaxseed oils, soybeans, and nuts. Foods rich in omega-6 fatty acids are meat, eggs, poultry, cereals, breads, baked goods, most vegetable oils, and margarine.

Hardman studied mice that were genetically predisposed to develop breast cancer.

During pregnancy, the mother mice were randomly assigned to a diet rich in either omega-6 or omega-3 fatty acids. After the baby mice were weaned at 3 months of age, they were again randomly assigned to a diet rich in either omega-6 or omega-3 fatty acids.

All of the baby mice exposed only to omega-6 fatty acids -- in the uterus, while nursing, and after weaning -- developed breast cancer by six months after birth, "which was expected in this mouse model," Hardman says.

"But fewer than 60% of the female offspring with diets rich in omega-3 fatty acids either maternally or after weaning developed [breast] tumors by 8 months," she says.

And only 13% of mice who were only given omega-3 fatty acids -- in the womb, during weaning and after birth -- developed breast tumors.

Omega-3s Block Estrogen.

Studies have shown that the hormone estrogen fuels the growth of breast tumors. And omega-3 fatty acids block the effects of estrogen, Hardman says. Other protective factors may also be at play.

It's going to take at least two generations to confirm the findings in humans, Hartman says.

In the meantime, Nelson says, there's no harm in talking with your doctor about the benefits of eating more fish, nuts, and other omega-3 fatty acid-rich foods during pregnancy: They're also good for the brain, heart, immune system, and just about all of our body systems, he says.

For pregnant women concerned about ingesting mercury pregnant women concerned about ingesting mercury in tuna and certain other fish, Hardman recommends fish oil supplements.

"But even two servings a week -- the current recommendation for pregnant women -- is still probably three or four times more than the average American gets," she says.

SOURCES: 96th Annual Meeting of the American Association for Cancer Research, Anaheim, Calif., April 16-20, 2005. W. Elaine Hardman, PhD, assistant professor, division of functional foods, Louisiana State University's Pennington Biomedical Research Center, Baton Rogue. William Nelson, MD, PhD, professor of oncology, Johns Hopkins University School of Medicine, Baltimore.

Reference Source 71
April 20 , 2005


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