A small study suggests younger non-smokers who eat more fruits, vegetables, and whole grains may have higher rates of lung cancer than the general population, and researchers speculate pesticide exposure on crops could be a factor. The findings were presented by University of Southern California investigators at the American Association for Cancer Research annual meeting in April; the work has not yet been published in a peer-reviewed journal.
Study overview
Researchers surveyed 187 people diagnosed with lung cancer by age 50. Participants provided information on smoking history, diet, and demographics. Most reported they had never smoked and had tumor types biologically different from smoking-related lung cancers.
The team used the Healthy Eating Index (HEI) to compare participants’ diets with the average U.S. score. Young non-smoking lung cancer patients averaged an HEI of 65 out of 100, versus the U.S. average of 57. Women in the patient group scored higher than men. On average, those with lung cancer reported eating more fruit, vegetables, and whole grains than the general population.
Hypothesis and rationale
The authors propose that pesticide residues on conventionally grown produce could be an environmental risk factor contributing to lung cancer in younger non-smokers. They point to previous studies showing agricultural workers with higher pesticide exposure have increased lung cancer rates. Because commercially produced fruits, vegetables, and whole grains can carry more pesticide residues than many processed foods or animal products, the researchers suggest this exposure pathway warrants further study.
Next steps and limitations
The researchers stress that additional research is needed to investigate the pesticide–lung cancer link. Their planned next step is to measure pesticide levels in blood and urine from lung cancer patients to confirm any association.
Experts caution this study is small, observational, and does not demonstrate causation. It did not directly measure pesticide exposure in participants, and other explanations — including genetic predispositions, ethnicity-related risks, or other environmental exposures — may contribute to rising lung cancer rates among younger non-smokers, particularly women.
Expert perspectives and practical advice
Several clinicians and dietitians not involved in the study urged caution in interpreting the results:
– Decades of evidence show diets high in fruits and vegetables reduce overall cancer risk. Experts say people should not reduce produce intake based on this single, preliminary study.
– Washing fruits and vegetables thoroughly under running water with light friction can reduce dirt, bacteria, and some pesticide residues and is recommended regardless of whether produce is organic.
– Frequenting local farmers’ markets, buying from trusted growers, or growing food at home can reduce uncertainty about pesticide use for those who can do so.
– Eliminating or drastically reducing pesticide use in agriculture would require major policy, economic, and farming-practice changes.
Context and concern
Although overall lung cancer rates and smoking prevalence have declined in the U.S. since the 1980s, that trend has not held for non-smokers 50 and younger. Women in this age group now appear more likely than men to develop lung cancer. The reasons remain unclear; experts suggest a mix of genetic factors and environmental exposures may be involved.
Conclusion
The USC study raises questions about potential environmental exposures linked to otherwise healthy diets, but it is preliminary and does not prove pesticides on produce cause lung cancer in younger non-smokers. Further research that directly measures pesticide exposure in patients is needed. Meanwhile, health professionals continue to recommend diets rich in fruits, vegetables, and whole grains and advise washing produce before eating.
