London, Feb 23 (IANS): Consuming five or more daily servings of diet rich in fruit such as apples or pears and green leafy vegetables may significantly lower the risk of developing chronic lung disease in both former and current smokers, finds a research.

Smoking is the primary risk factor for developing chronic obstructive pulmonary disease (COPD), which is set to become the third leading cause of death worldwide, according to World Health Organisation.

The findings, published online in the journal Thorax, showed that people who ate five or more portions of fruit and vegetables every day were, respectively, 40 per cent and 34 per cent, less likely to develop COPD -- respiratory condition that narrows the airways, which include bronchitis and emphysema.

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.

As oxidative tissue stress and inflammation may be involved in COPD development, and smoking is a potent trigger of these processes, the antioxidants abundant in fruit and vegetables may curb their impact, suggest the researchers," Joanna Kaluza from Warsaw University of Life Sciences in Poland.

On the other hand, both current and former smokers eating fewer than two daily portions were, respectively, 13.5 times and six times more likely to develop COPD.

While apples, pears, green leafy vegetables and peppers seemed to exert the strongest influence and depress the risk, no such associations were found of eating berry fruits, bananas, citrus fruits, cruciferous and root vegetables, tomatoes, onions, garlic or green peas, Kaluza added.

For the study, the team tracked the respiratory health of more than 44,000 Swedish men born between 1918 and 1952 and aged between 45 and 79 for 13 years up to the end of 2012.