Those who consume fruit and vegetables have a 40% lower risk of an incurable lung disease

Smokers should eat make sure they eat more fruit and vegetables to prevent deadly lung disease, scientists warn.

Consuming five-a-day reduces their risk of getting chronic obstructive pulmonary disease (COPD) by 40 per cent, a study found.

Each extra portion then slashes the chances by an additional eight per cent, the new research suggests.

Former smokers can also grab the benefits from adopting a healthier diet, although the findings weren′t true for those who do not smoke.

Known to contain powerful antioxidants, the Swedish experts believe that fresh produce may help to protect the lungs from smoking damage.

But the results show only a link between apples, leafy greens and peppers. No such benefits came from eating berries, tomatoes or onions.

Study author Dr Joanna Kaluza, of the Karolinska Institute in Stockholm, said: ′All smokers and former smokers should eat as much fruits and vegetables as possible.

′Each extra serving of fruit and vegetable decreases significantly risk of COPD development.

′High fruit and vegetable consumption not only reduces the risk of chronic lung disease, but also cardiovascular disease, cancers, helps to keep proper body weight and other benefits.′

COPD is an umbrella term for a number of lung conditions, including chronic bronchitis and emphysema.

Smoking is widely known to increase the risk of the incurable disease, which can be deadly.

Believed to affect about three million Britons, it can make breathing difficult for sufferers, leaving them wheezing and coughing.

The researchers analysed data of 44,335 middle-aged men over a period of 14 years, starting in 1998.

At the start of the study, the participants completed questionnaires about how often they consumed fruit and vegetables.

The five-a-day mantra to get us all to eat more healthily has been the official advice for decades.

But last month experts said that the guidelines should be doubled - to 10 portions of fruit and vegetables a day.

This would prevent 7,200 cancer deaths and almost 14,000 from stroke every year, Imperial College London researchers claimed.

They found ten 80g portions of fruit and vegetables may cut the risk of cancer by 13 per cent and heart disease by 24 per cent.

Their smoking history was also monitored and assessed. Some 1,918 went on to develop COPD by the time the study period finished.

Around two thirds of the men were current or former smokers, according to the findings published in the journal Thorax.

The researchers divided the participants into five groups based on how many fruit and vegetables they ate daily.

After separating them by their smoking status, researchers found a significantly lower risk of developing the disease.

Ex-smokers with high consumption of greens were 34 per cent less likely to develop COPD. Each additional serving was linked to a four per cent drop in risk.

The findings could not be replicated in those who had never smoked cigarettes.

Despite the promising findings, Seif Shaheen, a professor of respiratory epidemiology at Queen Mary University in London, stressed that diet is not a cure-all for the effects of smoking.

He said: ′The most important thing you can do to reduce your chances of getting COPD is not to smoke/to stop smoking.′