Pesticides on produce may play role in lung cancer in non-smokers

By Stephen Beech

A "healthy" diet featuring plenty of fruit and vegetables can increase the risk of lung cancer, suggests new research.

Eating fruits, greens and whole grains is usually recommended by doctors to lower the risk of several diseases. including cancer.

But it may actually put non-smokers under the age of 50 at greater risk of developing deadly lung cancer, say scientists.

Pesticide residue may play a role in higher rates of lung cancer in young non-smokers, according to the findings of the American study.

Lead investigator Dr. Jorge Nieva, a medical oncologist and lung cancer specialist at the University of Southern California (USC), said: "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.

"These counter-intuitive 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 fellow researchers believe that the risk factor may be pesticides used to keep crops pest-free.

He says commercially produced, non-organic fruit, vegetables and whole grains are more likely to be associated with a higher residue of pesticides than dairy, meat and many processed foods.

Nieva also noted that agricultural workers exposed to pesticides often have higher rates of lung cancer, which adds credence to the theory.

The study also showed that young women non-smokers have a higher incidence of lung cancer than men, and that women tended to also have a diet higher in produce and whole grains than men.

Nieva says lung cancer has traditionally been a disease that affects older adults with the average age of lung cancer onset being 71, men more than women, and smokers.

But smoking rates have fallen since the mid-1980s, which has led to fewer lung cancer cases across the United States, except among one unique group — non-smokers age 50 and younger, especially women, who are now more likely to get lung cancer than men.

To investigate the trend, researchers launched the Epidemiology of Young Lung Cancer Project, which surveyed 187 patients who were diagnosed with lung cancer by the age of 50.

Patients provided details on diet, demographic, their history of smoking and lung cancer diagnosis.

Most patients had never smoked and had a form of lung cancer biologically different from lung cancer caused by smoking.

A 2021 study found that the subtypes of lung cancer seen in people under 40 were distinct from lung cancer in older adults.

Researchers used the Healthy Eating Index (HEI), a ranking of the overall quality of Americans' diet on a scale of 1-100, to compare patients' diets with the broader U.S. population.

Young non-smoking lung cancer patients had an average HEI score of 65 out of 100, compared to the national average of 57.

Among participants in the study, women had higher HEI scores than men.

On average, the young lung cancer patients ate more daily servings of fruit, veggies and whole grains than the general population.

For example, participants averaged 4.3 servings of dark green vegetable and legumes and 3.9 servings of whole grains per day, while the average American adult eats 3.6 servings of dark green vegetables and legumes and 2.6 servings of whole grains per day.

Nieva says the link between pesticides and lung cancer in young people, especially women, needs more research.

The team did not test specific foods for pesticides in the study.

Instead, they used published data on average pesticide levels for food categories such as fruits, vegetables and grains to estimate exposure.

Nieva says the next step is to confirm the link by directly measuring pesticide levels in blood or urine samples from patients.

He said it could also help reveal whether or not some pesticides increase lung cancer risk more than others.

Nieva added: "This work represents a critical step toward identifying modifiable environmental factors that may contribute to lung cancer in young adults.

"Our hope is that these insights can guide both public health recommendations and future investigation into lung cancer prevention."

The findings are due to be presented at the annual meeting of the American Association for Cancer Research in San Diego, California.