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Breast-cancer risk may trace back to bubbe

It may come as no surprise that a pregnant woman should eat a well-balanced diet. But a new study suggests that proper nutrition may have a far greater impact on the health of a woman's descendants than previously suspected.

The provocative research indicates that if a woman eats too much fat during pregnancy, it may raise the breast cancer risk of the next two generations.

In other words, not only will her daughter face greater odds of developing breast cancer, but her granddaughter will be at heightened risk too.

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These findings are based on rat experiments conducted at Lombardi Comprehensive Cancer Center of Georgetown University Hospital in Washington.

For the study, the researchers fed two groups of pregnant rats the same number of calories each day. But one group consumed a larger portion of calories – 43 per cent of calories compared with 17 per cent – in the form of fat. The researchers found an elevated number of cancers in the mammary glands of both the daughters and granddaughters of the rats that gorged on fat, according to the study results presented this week in Washington at the annual meeting of American Association for Cancer Research.

How could a high-fat diet during pregnancy have a lasting effect on multiple generations? The study's lead investigator, Sonia de Assis, doesn't believe that genetic mutations are to blame. Instead, she thinks something far more subtle may be at work – epigenetic changes, or chemical modifications of DNA. These changes regulate gene activity, essentially turning genes on and off.

Eating a high-fat diet during the crucial period of fetal development may lead to epigenetic changes that make the offspring more susceptible to cancer later in life, speculated Dr. de Assis. And this flux in epigenetic regulation may also alter the germline, or reproductive cells of the offspring, so the changes get passed down to the next generation.

Of course, it's important to keep in mind that this study was carried out on rats. Researchers still have to demonstrate that a fat-laden diet would affect human offspring in a similar fashion.

Nonetheless, the work could help explain why breast cancer seems to run in some families. Scientists have been able to identify genetic mutations that are linked to only a small percentage of breast cancers. So, some other factors – possibly related to diet or lifestyle – may be playing a role in multigenerational cases of the disease.

Dr. de Assis noted that pregnant woman are already encouraged to eat nourishing, well-balanced meals – and this latest study adds another reason to do so.

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"I think we should keep driving home the message to pregnant women that they should eat a proper diet for their own health, for their baby's health and possibly for the health of future generations as well."

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