Mothers who have insufficient levels of B vitamins in their diet are more likely to have children with health problems such as obesity, researchers have claimed.
A study by scientists at the University of Nottingham found that disorders in adulthood can originate from conditions at the point of conception, particularly in men.
The researchers studied adult sheep whose parents had been deprived of B vitamins prior to conception.
Male offspring were found to be 25 per cent fatter and had higher blood pressure than offspring of sheep who were given a healthy diet with plenty of B vitamins.
According to the research, small reductions in parents' vitamin B12 and folate levels could lead to subtle changes in their children's DNA.
Commenting on the findings, which are published in the Proceedings of the National Academy of Sciences, researcher Dr Kevin Sinclair said: "Sweeping changes to our DNA take place during conception and we now realise that this period is particularly vulnerable to environmental influences that can affect development and lead to chemical modifications that can make permanent alterations to gene expression.
"If maternal diet is not properly balanced it can upset these processes during conception."
Mothers who have insufficient levels of B vitamins in their diet are more likely to have children with health problems such as obesity, researchers have claimed.
