The risk of being obese as a child can be predicted by DNA modifications that arise while in the womb, and may be influenced by the mother's diet, suggests a new study.
Researchers found that lower DNA methylation levels at a gene involved in appetite regulation, SLC6A4, at birth was associated with a higher fat mass during childhood.
'Our results add to the growing evidence that epigenetic changes detectable at birth are linked to a child's health as they grow up,' said co-lead author Professor Karen Lillycrop at the University of Southampton.
'Additionally, it also strengthens the body of evidence that shows a mother's health during pregnancy can affect the future health of her child. It could allow us to more accurately predict the future risk of obesity.'
The team examined methylation at the SLC6A4 gene as part of the EpiGen Global Consortium. This gene produces a serotonin transporter, and has a key role in mood and appetite regulation, leading the authors to hypothesise that differential levels of SLC6A4 methylation at birth might predict obesity levels later in life.
To test this, they took blood samples from the umbilical cords of just under 700 babies born in the Southampton's Women Survey, and compared levels of SLC6A4 methylation with the amount of fat tissue in the children when aged four and six years.
They found that lower DNA methylation levels of SLC6A4 at birth was associated with higher levels of fat mass at six to seven years of age. They also found that the mothers of those children with lower SLC6A4 methylation were more likely to have gained more weight during their pregnancies than those mothers of children with higher levels of SLC6A4 methylation. A lower number of previous births was also associated with lower SLC6A4 DNA methylation.
The results, published in the International Journal of Obesity, were also replicated in other groups of children and adults, including the Western Australian Pregnancy Cohort Study and the UK BIOCLAIMS cohort.
Professor Keith Godfrey, another member of the Southampton team, and director of the EpiGen Global Consortium, added: 'The new findings strengthen the case that primary prevention of childhood obesity needs to begin before birth.
'Ongoing research is examining whether diet and lifestyle interventions before and during pregnancy might be able to tackle and even reverse the childhood obesity epidemic.'