Two studies published in The Journal of Physiology show that events before birth can permanently change patterns of appetite and fat deposition in child and adult life. In the first study, researchers from Australia and Scotland are shedding new light on potential causes of child and adult obesity. They cite evidence which shows that there are strong associations between the prenatal experience and patterns of fat deposition and appetite regulation in postnatal life. In other words, a mother's diet can strongly influence the offspring's chances of being obese. The researchers, Prof I. C. McMillen and Dr C. L. Adam, say that prenatal exposure to either increased or decreased levels of nutrition before birth leads to an increased risk of obesity in postnatal life.
Linking prenatal exposures to patterns of postnatal feeding behavior, the researchers have addressed the question as to what extent the fetus has a functional capacity for regulating its appetite. McMillen and Adam believe they are the first to demonstrate that the fetus possesses all the components of the appetite-regulating system before birth, and that increases in nutritional supply are able to regulate the expression of these components. "The concept of a fetal appetite is a difficult and intriguing one. What our research suggests is that all the components of the system which we know regulates appetite in postnatal life are already there before birth and may be responding to signals of nutritional status. This, of course, raises the possibility that changes in the fetal environment can permanently change the way that this system develops and result in changes in feeding behavior after the individual is born," said co-researcher Beverly Mühlhäusler.
In the second study, researchers said that while many of us eat a diet high in saturated fat and sugars and do little exercise, there is emerging evidence that the diet that our mothers consume while we are in the womb and also when breast feeding may lead to obesity. For some time it has been understood that fetal undernutrition and low birthweight may "programme" the fetus to develop heart disease in adulthood - a phenomenon termed "developmental programming". Now, converging lines of evidence suggest that maternal overnutrition, and obesity in pregnancy, may be just as harmful to the developing baby as undernutrition. The study examines exposure to an energy rich diet during development and the researchers describe the consequences of a maternal diet that is high in fat or caloric intake. Overall, it appears that an individual's appetite and cardiovascular risk may be "programmed" by excess maternal energy intake so predisposing an individual to diabetes or raised blood pressure later in life.
The researchers conclude that they do not know what the ideal diet would be during pregnancy, however, they believe it is clear from the research that maternal obesity and a high saturated fat and calorie intake are not conducive to optimal development of the fetus and newborn, and may increase the risk of heart disease and diabetes in later life.
