People who consumed the most organic foods had a 25 percent lower cancer risk compared with those who ate the least, the study found.
Specifically, eating more organically grown foods was linked to a 34 percent reduced risk of postmenopausal breast cancer, a 76 percent decreased risk for all lymphomas and an 86 percent reduced risk for non-Hodgkin lymphoma, said lead researcher Julia Baudry. She is a scientist with the Center for Research and Epidemiology and Statistics at the Sorbonne Paris Cite.
“If our findings are confirmed, organic food consumption may contribute to cancer prevention,” Baudry said, though the study did not prove they directly caused cancer risk to drop.
And people shouldn’t stop eating fruits and vegetables if they can’t afford more expensive organically grown options.
Filling your diet with fruits and vegetables is known to reduce your risk of chronic disease and cancer, regardless of whether or not they’re organic, Baudry and other experts said.
Mark Guinter, a postdoctoral fellow with the American Cancer Society, said, “More importantly than anything is making sure you consume your fruits and vegetables, avoid your red and processed meat, and eat whole grains. Those are established relationships with cancer, replicated in multiple populations.”
Guinter added that “if people are interested in changing their diets or buying foods that are known to help prevent their cancer risk, those would certainly be avenues to take rather than simply buying organic.”
For this study, Baudry and her colleagues analyzed data from nearly 69,000 people taking part in an ongoing French study of the associations between nutrition and health.
The participants all filled out questionnaires regarding their consumption of organic products. These included fruits and vegetables, dairy, meat and fish, eggs, breads and other foods.
They also filled out annual questionnaires regarding the status of their health, including instances of cancer, and were followed for 4.5 years on average.
The researchers found an association between eating organic foods and lower cancer risk, even after taking into account other risk factors for cancer.
“We did consider a variety of factors that may be involved in the relationship,” Baudry said, “such as sociodemographic, socioeconomic and lifestyle factors, as well as family history of cancer, or healthier diet in terms of nutrients and food consumption. Controlling for these factors did not substantially modify the findings.”
Organic foods are grown without pesticides, fertilizers and other chemicals. Studies have shown that people who eat organic foods have lower levels of pesticide residue in their urine, she noted.
“Exposure to pesticide has been associated with higher cancer risk” in previous studies, Baudry said.
Specifically, Guinter said, this study supports results from a British study that also found an association between organic food consumption and lower risk for non-Hodgkin lymphoma.
“Whenever you see a result that’s replicated like that, you find it a little more believable. There’s good biologic plausibility behind it,” Guinter explained.
According to Dr. Frank Hu, chair of nutrition at the Harvard T.H. Chan School of Public Health, animal studies have shown that pesticides can increase DNA damage, which can increase risk of cancer. Chemicals also can disrupt the endocrine system.
But, Guinter and Hu said, there’s not enough human evidence yet upon which to base any new dietary recommendations.
People should eat right and maintain a healthy weight through diet and exercise to prevent cancer, Hu said. Cutting back on alcohol also will help.
“Basically, increasing consumption of fruits and vegetables, whether conventional or organic, can improve overall diet quality and reduce your risk of chronic disease, including cancer,” said Hu, senior author of an editorial accompanying the new study.