Surprising Association Found Between Healthy Diets and Young-Onset Lung Cancer in Nonsmokers

A new USC study finds a link between healthy diets and lung cancer in nonsmoking women. Researchers suspect pesticides may be the cause.

By: AXL Media

Published: May 1, 2026, 4:56 AM EDT

Source: Information for this report was sourced from Medical News Today and USC Norris Comprehensive Cancer Center

The Paradox of Healthy Eating and Lung Cancer

While overall lung cancer rates in the United States have been declining for decades, oncologists have noted a troubling rise in cases among younger adults under 50 who have never smoked. Researchers from the USC Norris Comprehensive Cancer Center examined data from the "Epidemiology of Young Lung Cancer" study to identify potential risk factors. Surprisingly, they found that patients with young-onset lung cancer often followed diets rich in dark green vegetables, legumes, and whole grains. Specifically, participants in the study had a Healthy Eating Index (HEI) score of approximately 65%, which is significantly higher than the U.S. adult average of 57%.

Investigating the Pesticide Hypothesis

The lead author of the study, Dr. Jorge Nieva, was quick to clarify that the findings should not discourage healthy eating. Instead, the team theorizes that the association may be rooted in environmental contaminants rather than the food itself. The researchers suspect that pesticide residues found on produce and whole grains may be the underlying factor. Because women in the U.S. statistically tend to consume healthier diets than men, they may inadvertently face higher relative exposure to agricultural chemicals. Future research will focus on measuring pesticide metabolites in lung cancer patients to determine if specific chemical substances correlate with tumor mutations.

The Role of Oral Contraceptives and Estrogen

Another significant finding in the cohort was the high rate of oral contraceptive use among female participants. In the groups identified with specific genetic mutations (EGFR and mixed mutations), approximately 77% of women reported a history of taking oral contraceptives, compared to a national average of roughly 11.4% for women in the same age bracket. Dr. Nieva noted that the EGFR mutation—the most common subtype in young-onset cases—often expresses estrogen receptors. This suggests a potential endocrine-related pathway that researchers intend to explore further to see if hormonal shifts contribute to cancer development in nonsmokers.