Women who always or mostly eat organic foods are no less likely to develop cancer than women who eat a more conventional diet, according to the study published in the British Journal of Cancer.
Cancer Research UK scientists from the University of Oxford found no evidence that regularly eating a diet that was grown free from pesticides reduced a woman's overall risk of cancer.
The researchers asked around 600,000 women aged 50 or over, who were part of a project, named Million Women Study, about whether they ate organic foods, and tracked the development of 16 of the most common types of cancer in a nine year period following the survey.
The scientists' analysis found no difference in overall cancer risk when comparing the 180,000 women who reported never eating organic food with around 45,000 women who reported usually or always eating organically grown food.
Also Read
When looking at the results for 16 individual types of cancer they found a small increase in risk for breast cancer but a reduction in the risk for non-Hodgkin lymphoma in women who mostly ate organic food, although these results could be partly due to chance and other factors.
"In this large study of middle-aged women in the UK we found no evidence that a woman's overall cancer risk was decreased if she generally ate organic food," said Professor Tim Key, a Cancer Research UK epidemiologist based at the University of Oxford and one of the study authors.
"This study adds to the evidence that eating organically grown food doesn't lower your overall cancer risk. But if you're anxious about pesticide residues on fruit and vegetables, it's a good idea to wash them before eating," said Dr Claire Knight, Cancer Research UK's health information manager.
"Scientists have estimated that over nine per cent of cancer cases in the UK may be linked to dietary factors, of which almost five per cent are linked to not eating enough fruit and vegetables.