Women who mostly or always eat organic foods have the same overall chance of developing cancer as women who never eat it, according to a new study from the UK's University of Oxford and published in the British Journal of Cancer that followed over 600,000 middle-aged women for nearly a decade.
One of the investigators, Tim Key, professor of epidemiology and deputy director of the Cancer Epidemiology Unit at Oxford, says:
"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."
In the European Union, the US, Canada, Mexico, Japan and other countries, to produce and market organic food you have to obtain a special licence.
The word "organic" and the standards that apply to it are slightly different in various countries, but generally it forbids the use of synthetic pesticides and chemical fertilizers in the production of food.
Outside the organic movement, pesticides are widely used in agriculture, and there are concerns that residues from these get into the food chain and could increase the risk of cancer. But so far, the evidence for this is not strong enough to give any clear answers.
No difference in overall cancer risk between women who did or did not eat organic food
For this latest study, the researchers examined data on 623,080 middle-aged UK women being followed in the Million Women Study, a large national study of UK women's health that is funded by Cancer Research UK and the Medical Research Council.
The investigators asked women whether they ate organic foods, and over a 9-year period, looked at how many developed 16 of the most common types of cancer.
Cancer risks do not differ between women who eat organic food and those who do not, researchers found.
The researchers could find no difference in overall cancer risk when they compared 180,000 women who said they never ate organic food with 45,000 who said they always or usually ate it.
When they looked in more detail at each of the 16 different cancers, the researchers found a slightly higher risk for breast cancer and a lower risk for non-Hodgkin lymphoma in women who said they mostly ate organic food. But they said this result could be due to chance and other factors.Dr. Claire Knight, health information manager at Cancer Research UK, says the study adds to increasing evidence that eating organic food does not lower the risk of developing cancer, but she suggests people should wash their fruits and vegetables before eating them if they are worried about pesticide residue.
She points out that whether fruit and vegetables are conventionally grown or not, it is important to eat a well-balanced diet rich in fruits and vegetables to reduce cancer risk:
"Scientists have estimated that over 9% of cancer cases in the UK may be linked to dietary factors, of which almost 5% are linked to not eating enough fruit and vegetables."
Medical News Today recently learned about new research that suggests being overweight or obese may increase risk for ovarian cancer. After reviewing 25 studies involving 4 million women - including 16,000 with ovarian cancer - researchers found that for every 5 additional body mass index (BMI) units, there was a 6% increase in the risk of developing ovarian cancer.