Fruits and Vegetables Linked to Lung Cancer Risk in Non-Smokers: What You Need to Know

A new study from researchers at the University of Southern California Norris Comprehensive Cancer Center has identified an unexpected association between healthy eating patterns and an increased risk of lung cancer in younger non-smokers, raising questions about potential hidden risks in commonly recommended foods.

The research, presented at the annual meeting of the American Association for Cancer Research, found that non-smoking Americans under age 50 who reported consuming higher quantities of fruits, vegetables, and whole grains than the general population were more likely to develop lung cancer. This finding contrasts with long-standing public health guidance that emphasizes plant-based diets for reducing cancer risk.

Jorge Nieva, MD, a medical oncologist and lung cancer specialist with USC Norris and lead investigator of the study, stated: “Our research shows that younger non-smokers who eat a higher quantity of healthy foods than the general population are more likely to develop lung cancer.” The study analyzed data from 187 patients with early-onset lung cancer, most of whom had never smoked.

While the study identifies a correlation between healthier diets and higher lung cancer rates in this specific group, researchers caution that it does not establish causation. Instead, they hypothesize that pesticide residues on conventionally grown produce could be a contributing factor. The researchers estimated probable pesticide exposure using average residue levels from other sources, as they did not directly measure pesticides in participants’ food or blood.

Experts note that this type of study, which looks backward from people who already have cancer, cannot determine whether diet played a role in causing the disease. As reported by The Conversation, such observational designs are limited in their ability to establish cause-and-effect relationships and are intended to generate hypotheses for further investigation rather than overturn established dietary advice.

Medical News Today highlighted that while fruits and vegetables themselves are not believed to cause lung cancer, the study’s authors suspect environmental factors like pesticide exposure may explain the observed association. The researchers also noted a similar pattern among women who use oral contraceptives, suggesting multiple factors may be involved in the rising incidence of lung cancer among young non-smokers.

Despite declining overall lung cancer rates in the United States due to reduced smoking, incidence trends among younger non-smokers—particularly women—have been increasing. Researchers emphasize that more evidence is needed to understand whether pesticide exposure from fruits and vegetables contributes to this trend, and they plan to investigate the hypothesis further in future studies.

Health authorities continue to recommend diets rich in fruits, vegetables, and whole grains for overall health and disease prevention. The study’s authors stress that their findings should not be interpreted as a reason to avoid these foods, but rather as a call for research into potential contaminants in the food supply that could pose unforeseen health risks.