A mice study has found that if obese women shed some extra weight before pregnancy, it has health benefits for their offspring.

In the study, researchers with the Center for Pregnancy and Newborn Research at the Health Science Center and the National Institute of Nutrition in Mexico City induced maternal obesity by feeding a group of female rats a high-fat diet prior to mating.

This group of females ate the fatty chow from weaning through adolescent life to breeding and remained on it through pregnancy and lactation. Meanwhile, females in a second group were switched to normal chow one month before mating.

Only male offspring were studied. At weaning, triglycerides, leptin, insulin and insulin resistance were elevated in offspring of obese mothers and all returned to normal if their mothers had received prepregnancy dietary intervention. Fat mass and fat cell size were increased in offspring of fat mothers and these changes were significantly reversed, though not completely abolished, by the dietary intervention.

Nutrition for you two

The authors said this is the first study showing reversibility of adverse metabolic effects of maternal obesity on offspring by a pre-pregnancy intervention. Outcomes and reversibility varied by tissue affected.

`It is of interest that offspring of the obese mothers also showed high levels of leptin, a hormone that signals the brain to decrease appetite. This may mean they`ve developed a brain that is resistant to the signals that tell them they`re getting fat, and they just go on eating and thus get fat as their mothers were. That is what we mean when we say that the effects are transgenerational. Leptin levels were normal in the offspring of the intervention group, showing that we can break this cycle,` said Nathanielsz.