Study finds new link between pregnancy diet and obesity

Study finds new link between pregnancy diet and obesity

Media release 19 April 2011

NZ scientists have helped produce the first objective data that quantify a link between events before birth and the risk of later disease, and provide a plausible explanation for how this occurs.

The study, led by researchers at the University of Southampton and including teams from New Zealand and Singapore, has shown for the first time that during pregnancy a mother's diet can alter the function of her child's DNA - through a process called epigenetic change - and this can lead to her child tending to lay down more fat. Importantly the study shows that this effect acts independently of how fat or thin the mother is and of the child's weight at birth.

Professor Sir Peter Gluckman, who led the New Zealand and Singapore arms of the study, says a substantial part of the project's success is due to the collaboration between The University of Auckland's Liggins Institute and Crown Research Institute AgResearch. He credits AgResearch scientists, in particular Dr Allan Sheppard, with contributing expertise in developmental epigenetics which allowed the team to prove their long-held theory.

Professor Gluckman says that some doctors and scientists have long suspected that a poor start to life plays a major role in the later development of heart disease, diabetes and obesity. However, despite numerous epidemiological and animal studies confirming this view, the model has largely been ignored by policy makers, physicians and public health practitioners for lack of objective human data.

In the current study, the team measured the epigenetic state (the degree of chemical modification) of DNA in umbilical cord tissue from nearly three hundred children and showed that this strongly predicted the degree of obesity at six or nine years of age. What surprised the researchers was the size of the effect - children vary in how fat they are, but measurement of the epigenetic change at birth allowed the researchers to predict 25% of this variation. This association is much stronger than explanations of obesity based on heredity and lifestyle.

In addition, they found that the degree of epigenetic change at birth was strongly associated with features of the mother's diet in the first third of pregnancy.

"The study demonstrates the importance of developmental factors before birth in the pathway to childhood obesity - and we already know that childhood obesity is an important predictor of later diabetes and heart disease," says Professor Gluckman.

"It confirms our suspicions that maternal nutrition does indeed influence the offspring's risk of later obesity and disease and that these factors are linked through epigenetic mechanisms. This is important as epigenetic profiles are not necessarily fixed, so there is the potential to halt progression towards disease through nutritional and or pharmacological interventions during early life.

"Finally, this study provides the most compelling argument yet for giving greater weight to improving maternal and infant health as a means of reducing the burden of chronic disease. It is manifestly insufficient to focus on interventions in the adult alone," he says.

The study team was led by Keith Godfrey, Professor of Epidemiology and Human Development at the University of Southampton. Members are part of an international consortium involving the Universities of Southampton and Singapore, the Singapore Institute for Clinical Sciences, the Liggins Institute of the University of Auckland, AgResearch New Zealand and the Medical Research Council Lifecourse Epidemiology Unit, University of Southampton.

Their findings will be published next week (26 April 2011) in the journal Diabetes. It is available ahead of publication at http://diabetes.diabetesjournals.org/content/early/2011/04/04/db10-0979.abstract.

ENDS

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