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March 18, 2010 Volume 31, No. 24

Gender impacts how babies’ genes are expressed in the womb

Maternal diet

Research might help mothers tailor nutrition during pregnancy

Most mothers are conscious of their diets while pregnant, knowing that diet can influence the development of their babies. According to a new study, certain foods might alter how certain genes are expressed in the placenta in mid-pregnancy. The extent to which these alterations occur depends on the babies’ gender.

MU researchers found that the placentas of developing female mice are better able to adapt to the mothers’ diets than those of developing male mice — even before the fetus begins producing sex hormones. This finding might explain why adult males appear to suffer more from the effects of nutritional stress they experienced while in the womb.

In her study, Cheryl Rosenfeld, assistant professor of biomedical sciences, examined gene expression in mice that were fed high-fat, high-carbohydrate diets versus nutrient-balanced diets.

“From previous animal studies, we know that maternal diet affects all offspring, but that males are more affected,” Rosenfeld says. “In our recent study, we examined how genes might be altered based on the type of diet a mother consumes while she is pregnant. In this case, we found that many genes are affected by diet and that male and female placentas respond differently. Curiously, some of these genes also affect the kidneys, as well as control water and salt movement in the body. Other genes that could be affected are responsible for olfactory function, or ability to smell.”

Rosenfeld suggests that findings such as these might help physicians and mothers tailor prenatal nutrition regimens to improve fetal health, thereby reducing a child’s risk of diet-related, late-onset diseases, such as hypertension and diabetes.

The researchers were surprised to find just how many genes were regulated by maternal diet. Rosenfeld says that the noticeable increased sensitivity of the female placenta might serve as a buffer to protect the female against disturbances to compounds absorbed from the mother’s intestine after a fatty meal. She says this might explain why females have a decreased risk for adult diseases compared to males who are born to women who eat a high-fat diet or are obese at the time of pregnancy.

The study, “Contrasting Effects of Different Maternal Diets on Sexually Dimorphic Gene Expression in the Murine Placenta,” was published online in the Proceedings of the National Academy of Sciences (PNAS) in March.