A diet packed with fruits, vegetables, and whole grains is widely considered healthy and typically seen as a cornerstone of disease prevention.
But new research from the USC Norris Comprehensive Cancer Center, part of Keck Medicine of USC, suggests the relationship may be more complex.
Findings presented at the annual meeting of the American Association for Cancer Research indicate that non-smoking Americans under 50 who follow these diets may face a higher risk of developing lung cancer.
“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,” said Jorge Nieva, MD, a medical oncologist and lung cancer specialist with USC Norris and lead investigator of the study. “These counterintuitive findings raise important questions about an unknown environmental risk factor for lung cancer related to otherwise beneficial food that needs to be addressed.”
Nieva and his team suggest that pesticide exposure could help explain the pattern. According to Nieva, commercially produced fruits, vegetables, and whole grains tend to carry higher pesticide residues than dairy, meat, and many processed foods. He also noted that agricultural workers who are regularly exposed to pesticides often have higher rates of lung cancer, which supports this hypothesis.
A New Epidemic of Lung Cancer
Lung cancer has traditionally affected older adults, with an average age of onset of 71, and has been more common in men and in people who smoke.
Since smoking rates have declined since the mid-1980s, overall lung cancer cases in the United States have dropped. An exception has emerged among non-smokers age 50 and younger, especially women, who are now more likely than men to develop the disease.
To better understand this shift, researchers launched the Epidemiology of Young Lung Cancer Project and surveyed 187 patients diagnosed with lung cancer by age 50. Participants shared information about demographics, diet, smoking history, and diagnosis.
Most participants had never smoked and developed a form of lung cancer that differs biologically from smoking-related cases. A 2021 study from the Epidemiology of Young Lung Cancer Project and the Genomics of Young Lung Cancer Project found that lung cancer subtypes in people under 40 are distinct from those seen in older adults.
