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20 February 2019, 14:28 | Updated: 20 February 2019, 14:30
A child's risk of obesity as they grow up can be influenced by modifications to their DNA which occur while in the womb and are linked to the mother's health, according to a new study.
Researchers at the University of Southampton have found these changes, known as epigenetic modifications, control the activity of genes and can lead to a greater development of fat tissue as a child grows up.
Co-lead author Karen Lillycrop, from the University of Southampton, said: "Our results add to the growing evidence that epigenetic changes detectable at birth are linked to a child's health as they grow up.
"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."
A university spokesman explained: "One of the main epigenetic modifications is DNA methylation, which plays a key role in the development of the embryo and the formation of different cell types, regulating when and where genes are switched on.
"DNA methylation can be affected by a range of environmental factors such as parental health, diet and lifestyle."
He explained the researchers examined samples from umbilical cord tissues of babies born in the Southampton Women's Survey at birth and compared them with the amount of fat tissue in the child at four and six years of age.
They analysed the levels of DNA methylation at the SLC6A4 gene which affects serotonin levels in the body and has been implicated in mood and appetite regulation.
He said: "They found that lower DNA methylation levels at the SLC6A4 gene at birth was associated with a higher fat mass at six to seven years of age.
"Each unit lower of SLC6A4 methylation at birth was associated with a 7% higher child's fat mass at age six years.
"The Southampton team compared the results to the mother's health during pregnancy and found that higher weight gain during pregnancy and a lower number of previous births was associated with lower SLC6A4 DNA methylation."
Professor Keith Godfrey, a member of the research team and director of the EpiGen Global Consortium, said: "The new findings strengthen the case that primary prevention of childhood obesity needs to begin before birth, and might 'reset' appetite levels in ways that protect infants and children from putting on excessive weight.
"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."
The university spokesman said that the results, published in the International Journal of Obesity, were replicated in other groups of children and adults, notably the Western Australian Pregnancy Cohort Study and the UK BIOCLAIMS cohort.