Pregnant women who gorge on fatty foods may increase the chances of their daughters and even grand-daughters developing breast cancer in later life.
Researchers believe eating an unhealthy diet can permanently alter the cells of an unborn baby – and future generations.
It suggests eating well in pregnancy could reduce levels of breast cancer, the most common cancer in the UK affecting one in eight women during their lives.
Scientists at Georgetown University in Washington DC fed pregnant rats either a normal diet or one much higher in fat.
For those on the fatty diet, their daughters and grand-daughters which were fed normally, were found to have a significantly higher risk of developing breast cancer tumours.
A fatty diet is linked to higher levels of the female sex hormone oestrogen. Another group of rat on the high fat diet who were also given oestrogen supplements, affected the next three generations.
While the findings have not been confirmed in humans, lead author, Dr Sonia de Assis said: ‘What a mother eats or is exposed to during pregnancy can increase her daughter’s breast cancer risk.
‘What we found for the first time is that increased breast risk of those daughters can be passed down to grand-daughters and even great-grand daughters and that is without any further exposures.
‘This study is important because it may help our understanding of the origins of some breast cancers.’