A study published on October 22nd, 2018, in JAMA Internal Medicine found that people who consume high amounts of organic food have a smaller cancer risk.
The study was performed on 68,946 French adults between May 10th, 2009, and November 30th, 2016. 78% of the participants were female, the average age at the beginning of the study was 44.2 years old with a standard deviation of 14.5 years, and at the beginning of the study all participants were cancer free. Participants reported their consumption of labeled organic foods, from which the researchers computed an organic food score.
At the end of the study, 1340 cancer cases were identified. Breast cancer was the most common, with 459 cases; there were 180 cases of prostate cancer, 135 of skin cancer, 99 of colorectal cancer, 47 of non-Hodgkin lymphoma, and 15 of other lymphoma.
High organic food scores were inversely associated with the overall risk of cancer. Specifically, non-Hodgkin lymphoma risk decreased by 86%, all lymphoma risk decreased by 76%, and postmenopausal breast cancer risk decreased by 34%. The p value—the likelihood that these results, with this method, could have been obtained through chance—was .001.
The researchers, Julia Baudry et al, theorize that these results are due to the lack of pesticides in organic food. They suggest the possibility that pesticide residues induce structural DNA damage, that they alter DNA in such a way that it leads to increased susceptibility to cancer, that they cause disorders at the mitochondrion level, or that they disturb cell homeostasis. The fact that pesticides often disrupt the endocrine system could explain the high rate of breast cancer.
They do list limitations of the study. The participants were volunteers, who were likely already health-conscious. They were mostly well-educated women, and exhibited healthier behaviors than the general French population. Organic food consumption was self-reported on a questionnaire, and quantitative consumption data over the course of the study was not available, leaving room for misclassification and for alterations in diet over the course of the study. And, of course, those participants who did not develop cancer might still develop cancer.
Still, the study is promising. The Organic Center, in a press release, called the results “striking,” particularly given the fact that the research team controlled for confounding variables such as dietary patterns and other lifestyle factors. They suggest that a “healthy diet should include an organic component,” as eating organic could prove to be a “critical tool for fighting an epidemic that is diagnosed in new patients over a million times per year.”