London, Feb 4 (IANS): Besides quitting smoking, eating a diet rich in whole grains, polyunsaturated fats and nuts can help reduce the risk of chronic lung disease, a new research has found.

Chronic obstructive pulmonary disease or COPD is an umbrella term for chronic lung diseases, such as emphysema and bronchitis, which block the airways and restrict oxygen flow around the body.

"Although efforts to prevent COPD should continue to focus on smoking cessation, these prospective findings support the importance of a healthy diet in multi-interventional programmes to prevent COPD," said the authors.

COPD is currently ranked the third leading cause of death worldwide.

Although the predominant risk factor for COPD is cigarette smoking, up to one third of COPD patients have never smoked, suggesting that other factors are involved.

So the researchers investigated the association between the Alternate Healthy Eating Index 2010 (AHEI-2010) - a measure of diet quality - and the risk of COPD.

They analysed data for more than 120,000 US men and women taking part in the Nurses' Health Study from 1984 to 2000 and the Health Professionals Follow-up Study from 1986 to 1998.

The risk of newly diagnosed COPD was one third lower in participants who ate the healthiest AHEI-2010 diet compared with those who ate the least healthy diet.

The AHEI-2010 diet score is based on 11 components, with a higher score reflecting high intakes of vegetables, whole grains, polyunsaturated fats, nuts, and long chain omega-3 fats - moderate intake of alcohol - and low intakes of red and processed meats, refined grains, and sugar sweetened drinks.

The study appeared in the journal The BMJ.