Mother's diet can alter the function of her child's DNA

Scientists have discovered that a mother's nutrition during pregnancy can strongly influence her child's risk of obesity many years later.

An international study, led by University of Southampton researchers 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. The process, called epigenetic change, 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 child's weight at birth.

Keith Godfrey, Professor of Epidemiology and Human Development at the University of Southampton, who led the study, says: ''We have shown for the first time that susceptibility to obesity cannot simply be attributed to the combination of our genes and our lifestyle, but can be triggered by influences on a baby's development in the womb, including what the mother ate. A mother's nutrition while pregnant can cause important epigenetic changes that contribute to her offspring's risk of obesity during childhood.''

Researchers measured epigenetic changes in nearly 300 children at birth and showed that these strongly predicted the degree of obesity at six or nine years of age. What was surprising to 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 per cent of this variation.

The study was primarily funded by the UK Medical Research Council (MRC), the National Institute for Health Research, WellChild (previously Children Nationwide), Arthritis Research UK and the University of Southampton.

The epigenetic changes, which alter the function of our DNA without changing the actual DNA sequence inherited from the mother and father, can also influence how a person responds to lifestyle factors such as diet or exercise for many years to come.