A small, preliminary study presented by University of Southern California investigators at the American Association for Cancer Research annual meeting suggests a possible association between pesticide exposure from produce and higher lung cancer rates in people diagnosed before age 50. The work has not yet been published in a peer-reviewed journal.
Study summary
Researchers surveyed 187 people who had been diagnosed with lung cancer by age 50. Participants provided information on smoking history, diet, and demographic background. Most of the patients reported they had never smoked, and many had tumor types that are biologically distinct from the smoking-related lung cancers typically seen in older adults.
The team compared participants’ diets to national averages using the Healthy Eating Index (HEI). On average the young lung cancer patients scored 65 out of 100 on the HEI versus a U.S. average of 57; women in the patient group scored higher than men. The investigators found that, on average, these patients reported eating more fruits, vegetables, and whole grains than the general population.
Hypothesis and rationale
Because commercially grown produce and some grains can carry pesticide residues, the authors propose that pesticide exposure from conventionally produced fruits, vegetables, and whole grains could be an environmental contributor to lung cancer in younger non-smokers. They point to prior occupational studies showing elevated lung cancer rates among agricultural workers with higher pesticide exposures as part of the rationale for this hypothesis.
Next steps planned
The researchers emphasize that their results are exploratory and call for further study. Their proposed next step is to directly measure pesticide biomarkers in blood and urine from lung cancer patients to assess whether higher internal pesticide levels are associated with diagnosis. Direct exposure measurement would be needed to evaluate any causal relationship.
Limitations
Experts caution that this is a small observational study that cannot prove causation. It relied on self-reported dietary data and did not measure individual pesticide exposure, so the proposed link between produce consumption and pesticides is speculative. Other explanations—genetic predisposition, ethnicity-related risk patterns, other environmental exposures, or chance—may account for the observations. The findings should be treated as hypothesis-generating rather than definitive.
Expert perspectives and practical advice
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; one preliminary study does not justify cutting back on produce.
– Washing fruits and vegetables under running water with gentle rubbing can remove dirt, bacteria, and some pesticide residues and is recommended regardless of whether produce is labeled organic.
– People who want to reduce uncertainty about pesticide use can consider buying from trusted local growers or farmers’ markets, choosing organic options when feasible, or growing some produce at home.
– Reducing or eliminating pesticide use in mainstream agriculture would require major policy, economic, and farming-practice changes.
Context
Overall U.S. lung cancer rates and smoking prevalence have declined since the 1980s, but that trend has not been uniform in younger non-smokers. Incidence appears to be rising in some groups under 50, and recent reports note that women in this age range may now be more likely than men to develop lung cancer. The reasons are unclear and likely involve a mix of genetic, biological, and environmental factors.
Bottom line
The USC study raises an intriguing question about potential environmental exposures tied to otherwise healthy diets, but it is preliminary and does not demonstrate that pesticide residues on produce cause lung cancer in younger non-smokers. Larger studies that directly measure pesticide exposure, account for genetics and other risk factors, and are peer-reviewed are needed. In the meantime, health professionals continue to recommend diets rich in fruits, vegetables, and whole grains and suggest simple steps—like thorough washing—to reduce potential residues on produce.