Smokers can reduce their risk of chronic lung disease by having more fruit and veg
Having more than five servings of fruit and veg cut the risk by over a third compared to those who ate less than two portions.
Each extra daily portion of apples, pears, green leafy vegetables and peppers was associated with a four to eight per cent reduction in risk of Chronic obstructive pulmonary disease or COPD.
But berries, bananas, citrus fruits, broccoli, cabbage, root vegetable, tomatoes, onions, garlic, or green peas "was not significantly associated with COPD," according to researchers.
Although the risk reduction was down to their antioxidant properties the best defence is not to smoke or quit, scientists at the Karolinska Institutet in Stockholm and Warsaw University of Life Sciences said.
COPD, forecast to become the world's third biggest killer, is the name for a group of lung conditions that cause breathing difficulties including bronchitis and emphysema.
Having more than five servings of fruit and veg can cut the risk
Non-smoking and smoking cessation remain the main public health message to prevent development of COPD
The lungs become inflamed, damaged and narrowed with smoking the main cause.
Diet may be an important factor in the development and prevention of COPD.
For example a diet high in fruits, vegetables, whole grains, polyunsaturated fatty acids, nuts and long chain omega-3 fats and low consumption of red and processed meat, refined grains and sugary drinks was associated with a lower risk of COPD.
In the study published in medical journal Thorax Dr Joanna Kaluza said: "Oxidative stress induced by cigarette smoking is now recognised as a major predisposing factor in the pathogeneses of COPD.
"It was observed that antioxidant capacity in patients with COPD is substantially reduced as a result of cigarette smoking, with oxidative stress persisting long after the cessation of cigarette smoking, due to the continued endogenous production of reactive oxygen species.
"Thus, it can be hypothesised that high consumption of fruits and vegetables, a rich source of antioxidants, may protect the lung against oxidative damage and prevent COPD."
Researchers made their findings after tracking the health and diets of more than 44,000 men aged between 45 and 79 over 13 years.
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Smokers and ex smokers who ate five or more daily servings of fruit and vegetable were 40 per cent and 34 per cent less likely to develop lung disease than those eating two or fewer daily servings
Each additional serving was associated with a four per cent lower risk of COPD in former smokers and an eight per cent lower risk in current smokers.
Compared with those who had never smoked and who ate five or more portions of fruit and vegetables, current and former smokers eating fewer than two daily portions were, respectively, 13.5 times and 6 times more likely to develop COPD.
The lungs become inflamed, damaged and narrowed with smoking the main cause
Dr Kaluza concluded: "High fruit and vegetable consumption was inversely associated with COPD incidence among smokers, but not among non-smokers.
"The present findings confirm the strong impact of cigarette smoking on the development of COPD and also indicate that diet rich in fruit and vegetables may have an important role in prevention of COPD.
"Nevertheless, non-smoking and smoking cessation remain the main public health message to prevent development of COPD."