Do Fruits and Veggies Raise Lung Cancer Risk? Study Raises Pesticide Questions

A new study suggests that young non-smokers who eat more fruits, vegetables, and whole grains may have a higher chance of developing lung cancer than the average person.

Researchers from the University of Southern California shared their findings at the American Association for Cancer Research annual meeting in April. The study has not yet been published in a peer-reviewed journal, but the scientists believe pesticides used on crops could be the reason behind the link.

“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 Dr. Jorge Nieva, a medical oncologist at USC Norris and the lead investigator, in a statement.

He called the results “counter-intuitive” and said they raise important questions about an unknown environmental risk tied to otherwise healthy foods.

The researchers point out that non-organic fruits, vegetables, and whole grains sold in stores often contain more pesticides than many processed foods, meat, and dairy. Past studies have shown that farm workers exposed to pesticides have higher rates of lung cancer, which could support this idea.

Lung cancer rates in the U.S. have been dropping since the 1980s, along with smoking rates. However, this is not true for non-smokers aged 50 and younger, especially women. Women in this age group are now more likely than men to get lung cancer.

“This trend is quite concerning. I think it is important for us to better understand through research why non-smokers are getting lung cancer,” said Dr. Jimmy Johannes, a pulmonologist at MemorialCare Long Beach Medical Center who was not part of the study.

What the Study Found

For the study, researchers surveyed 187 patients who had been diagnosed with lung cancer by age 50. Participants shared details about their smoking history, diet, and background.

Most of them said they had never smoked. They also had a type of lung cancer that is biologically different from the kind caused by smoking.

The researchers used the Healthy Eating Index (HEI) to compare the diets of these patients to the general U.S. population. The HEI scores diets on a scale of 1 to 100.

Young non-smoking lung cancer patients had an average HEI score of 65, compared to the U.S. average of 57. Women scored higher than men. Overall, those with lung cancer ate more fruits, vegetables, and whole grains than the average American.

Are Pesticides the Cause?

The study authors say more research is needed to confirm the link between pesticides and lung cancer in young people, especially women. Their next step would be to measure pesticide levels in blood and urine samples from lung cancer patients.

“This work represents a critical step toward identifying modifiable environmental factors that may contribute to lung cancer in young adults,” Nieva said.

Despite the findings, experts warn that people should not stop eating fruits and vegetables. The study is small and does not prove that pesticides cause lung cancer.

“This study raises an important question, but doesn’t directly measure pesticide exposure in participants. Decades of evidence still show that diets rich in fruits and vegetables help lower cancer risk. People should not reduce their intake of plant foods based on this study alone,” said Melissa Mroz-Planells, a registered dietitian nutritionist.

The Known Risks of Pesticides

Pesticides are known to be cancer-causing substances. But removing them from farming would require major changes to the food system.

“Pesticides and herbicides are poison. They’re meant to kill pests and bugs. They were developed during wartime… and now are sprayed on almost everything and contaminate much of the food supply,” said Dr. Dana Hunnes, a senior dietitian at UCLA Health who was not involved in the study.

She added that pesticides should be discussed in dietary guidelines but that eliminating them would require political will and money to change how food is grown.

Dr. George Chaux, a pulmonologist at Providence Saint John’s Health Center, said the rise in lung cancer among young non-smokers is concerning but still rare. He noted that it is often linked to genetics and ethnicity, such as people of Asian descent.

“Pesticides are known to be carcinogens, and there is a higher risk of lung cancer associated with heavy exposure, such as in agriculture workers,” he said. “This is why washing your fruits and vegetables before eating raw foods is very important.”

He added: “I would not conclude from this data nor recommend that people stay away from a healthy diet of fruits and vegetables… The best approach is to wash your fruits and vegetables well before you eat them.”

How to Lower Your Pesticide Exposure

Experts say washing produce is a simple and effective way to reduce pesticide residue.

“When eating fresh produce, I first encourage my patients to thoroughly wash all produce that they consume, regardless of the produce being organic or conventional. Rinsing under cold water and using a light friction can reduce bacteria, dirt, chemicals, and pesticides,” said Amy Bragagnini, a clinical oncology dietitian at Trinity Health Lacks Cancer Center.

She also suggested shopping at local farmers’ markets or growing your own produce if possible. “There is nothing more satisfying than picking ingredients for your family’s salad right out of your backyard,” she said.