The idea that fruit and vegetables might cause cancer sounds bizarre. For decades, studies have shown that people who eat more plants tend to live longer, healthier lives, with lower rates of heart disease, stroke and several common cancers.

Lung cancer is no exception: in many large studies, higher intakes of fruits and vegetables are linked with lower risks, especially in smokers.

Against that backdrop, a new suggestion that fruit and veg might be driving lung cancer in young adults is surprising.

The story behind this latest wave of anxiety doesn’t come from a definitive, landmark trial. It comes from a brief presentation at a scientific conference, based on 187 people with early‑onset lung cancer.

Most had never smoked. When researchers asked about their diets, a lot of them reported eating plenty of fruits, vegetables and whole grains – the sort of pattern most of us would call “healthy”.

Instead of measuring pesticides in their food or blood, the team estimated probable pesticide exposure using average residue levels from other sources. From there, they speculated that pesticides on otherwise healthy foods might help explain why some young non‑smokers develop lung cancer.

That is a very long way from proving that fruit and vegetables themselves are harmful. Studies like this are meant to raise questions – “could pesticides be part of the story in young lung cancer?” – not to rewrite dietary advice on their own.

Crucially, this particular study looks backwards from people who already have cancer, rather than following healthy people........

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