City of Hope nutritionists weigh in on study that says eating organic prevents cancer

October 25, 2018 | by Samantha Bonar

A study published Oct. 22 in JAMA Internal Medicine found that those who frequently eat organic foods lower their overall risk of developing cancer, in particular non-Hodgkin's lymphoma and postmenopausal breast cancer.
The French study examined the diets of nearly 70,000 adult volunteers, mostly white women in their mid-40s. They were followed for an average of four and a half years. The researchers found that those who ate the most organic food were 25 percent less likely to develop cancer. Specifically, they were 73 percent less likely to develop non-Hodgkin's lymphoma and 21 percent less likely to develop postmenopausal breast cancer.
Before you fill your grocery cart with all-organic produce, City of Hope nutritionists Elaine Siu, M.S., R.D., C.N.S.C., and Dhvani Bhatt, M.S., R.D., C.D.E., would like to offer some “food for thought” about this study.
While Siu and Bhatt find the study “thought-provoking,” they think it is “too early to recommend everyone start eating only organic foods.” Here are a few of their reasons why:
  • This is an observational study — it shows association, but it does not show that eating organic foods causes reduction in cancer risk.
  • The study is not consistent with other studies’ results.
  • The study asks the subjects to self-report their organic food intake, which can be highly variable and subjective. We do not know how much pesticide they actually consumed. We assume that those who say that they ate more organic had less pesticide exposure, but this is not confirmed in this study.
  • Even though the authors did try to control for other variables, the subjects were not random — they were mostly women, and they were volunteers who were more likely to consume organic to begin with. People who buy organic foods are more likely to be well-educated and of a high socioeconomic status. There are many co-factors and variables that need to be controlled in order to confirm this association.
“It is not a bad idea to buy organic if people have extra resources,” Siu said. “However, the more important thing to do is to eat more fruits and vegetables (organic or conventionally grown). Most people have limited resources; therefore, if they have to choose to eat two servings of organic fruits and vegetables vs. eating five servings of conventionally grown fruits and vegetables, it is more important to eat that five servings of conventionally grown fruits and vegetables than to eat less.”
Eating a diet rich in fruit, vegetables, whole grains and beans is one of the American Institute for Cancer Research’s top 10 recommendations for cancer prevention, Siu said. “Their recommendation is at least 400 grams or 15 ounces of nonstarchy vegetables or fruit per day.”
 “Until more studies can confirm the benefits of eating organic, we would recommend people reduce their pesticide exposures by washing their produce thoroughly,” Bhatt added. “According to the Center for Science and Environment, almost 75 to 80 percent of pesticide residues are removed by simply washing produce with cold water. People who are concerned can also choose to buy organic from the EWG's ‘Dirty Dozen list’ of fruit and vegetables that tend to have more pesticide residuals than other produce such as strawberries, spinach, nectarines, apples, grapes, peaches, cherries, pears, tomatoes, celery, potatoes and sweet bell peppers.”
“We definitely look forward to seeing more studies in this area to confirm this study’s findings,” Siu said.  

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