London: Struggling to shed those extra kilos even after following a strict diet regime? Then, blame it on your mother, scientists say.
A team at the Newcastle University in the UK found that some people are programmed to be fat while still in the womb, with a mother-to-be`s lifestyle affecting the health of her baby for years to come.
They found changes around their DNA at birth which may result from their mother`s diet or exposure to pollution or stress. They then linked these changes to a higher Body Mass Index (BMI) in children aged about nine years of age.
The researchers, however, said more work is needed to definitively prove the link between these changes and obesity.
Dr Caroline Relton, who led the research, said: "Other studies have just taken genes at birth and looked at differences irrespective of whether they are differently expressed with different levels of obesity."
"The difference between this study and others is that we had a reason to focus on the genes we looked at because we knew they were differently expressed in children with a higher BMI," he told the BBC.
Childhood or adult obesity has many causes and scientists have previously linked specific genes, such as the FTO gene, with increased body weight. Others have looked at molecular changes, called epigenetics, which can play a role in how a gene functions in the body, switching genes on and off.
For their research, published in the journal Plos One, Dr Relton and his team took blood samples from 24 children aged 11 to 13 and looked for differences in the way genes are "expressed" or encoded into the many proteins which we need to grow and function.
They identified epigenetic changes in 29 genes which could be associated with higher body mass among the children.
They then looked at data from a larger study of 178 individuals, for whom there were both cord blood samples from birth, and body composition data from aged about nine.
Among these individuals, epigenetic changes to nine of the 29 genes previously identified appeared to correspond to increased body weight, although only one of these associated changes withstood rigorous further analysis, the team said.
However, Dr Relton said more research is needed to prove the epigenetic differences observed at birth and originating in the womb, are actually contributing to obesity.
"While we have discovered an association between these genes and body size in childhood we need to carry out further studies to establish whether influencing the expression of these genes by altering epigenetic patterns is indeed a trigger to obesity."
Commenting on the paper, Prof Gudrun Moore of University College London said: "The paper is an interesting study on epigentic variations and their potential association with body size indices."
Prof Tim Spector of King`s College London, said the paper represented "an exciting piece of research exploring new ways of looking at the causes of obesity".