Study details

For the study, which was presented at the annual meeting of the American Association for Cancer Research, the researchers wanted to investigate why rates of lung cancer among nonsmokers age 50 and younger, especially women, have remained elevated.

To do this, they surveyed 187 patients who were diagnosed with lung cancer by age 50. These patients provided details on their demographics, diet, smoking history, and lung cancer diagnosis.

The majority of patients had never smoked and had a form of lung cancer that was biologically different from the type of lung cancer caused by smoking.

The researchers used the Healthy Eating Index (HEI) to rank the overall quality of each patient's diet on a scale of 1-100 in order compare their diet with the broader U.S. population. Young nonsmoking lung cancer patients had an average HEI score of 65 out of 100 compared to the national average of 57. Among the participants in the study, women had higher HEI scores than men.

On average, the researchers found that younger lung cancer patients ate more daily servings of fruit, vegetables, and whole grains than the rest of the general population. For example, participants in the study averaged 4.3 servings of dark green vegetables and legumes and 3.9 servings of whole grains per day, while the average U.S. adult eats 3.6 servings of dark green vegetables and legumes and 2.6 servings of whole grains each day.

The study also found that young women who don't smoke have a higher incidence of lung cancer than men, and that women also typically had a diet higher in produce and whole grains than men.

The researchers in the study didn't test specific foods for pesticides but instead used published data on average pesticide levels for food categories like fruits, vegetables, and grains to estimate exposure.

Discussion

According to Nieva, the link between pesticides and lung cancer in young people, especially in women, needs more research. The next step would be to confirm the link directly by measuring pesticide levels in blood or urine samples from patients, which could help reveal whether some pesticides increase lung cancer risk more than others.

Peter Shields, emeritus professor of medical oncology at Ohio State University, noted that being lean, which a person who has a diet heavy in fruits, vegetables, and whole grains could be, is known to correlate with lung cancer. "The authors may not be seeing anything more than this," he said.

"And, even more important, a role for pesticides is entirely speculative," he added, concluding that "the well-known benefits for eating fruits and vegetables … far outweigh any speculation of data interpretation from this study."

George Chaux, a board-certified interventional pulmonologist and medical director of interventional pulmonology at Providence Saint John's Health Center, noted that pesticides are "known to be carcinogens" and that they're associated with lung cancer at heavy exposure rates, like in agriculture workers.

"This is why washing your fruits and vegetables before eating raw foods is very important," he said. "I would not conclude from this data nor recommend that people stay away from a healthy diet of fruits and vegetables, which has been conclusively shown to improve overall health, including risk of colon cancer and heart disease. I would also not necessarily recommend organic foods, which tend to be more expensive; the best approach is to wash your fruits and vegetables well before you eat them."