An Apple A Day May Keep The Pulmonologist Away

British Researchers Report Apples May Improve Lung Function

McLean, VA. – New research suggests we can all breathe easier – literally – by eating an apple a day. Researchers at the University of Nottingham in the United Kingdom report that persons eating more than five apples a week – the proverbial “apple a day” – had better lung function and lower risk of respiratory disease such as asthma than non-apple eaters. Apple eaters also reported less wheezing, researchers said. Their report was based on a study of the potential relationship between foods and respiratory health in 2,633 adults between 1991 and 2000.

Lung function was evaluated based on self-reports of wheezing, physician-diagnosed asthma and measured forced expiratory volume, or the force with which a person can exhale air. Persons with strong lung function can forcefully exhale more air than persons with poor lung function. “We suspect that what we are seeing is an antioxidant effect,” University of Nottingham lead researcher Dr. Emma Broadfield told Reuters Health, noting apples’ high antioxidant content. Antioxidants counter the natural although sometimes damaging transformation of cells that have been oxidized – that is, exposed to oxygen in the body.

According to figures from the Centers for Disease Control and Prevention (CDC), the prevalence of asthma has grown 75 percent between 1980 and 1994. The American Cancer Society reports that lung cancer is the leading cause of cancer deaths in the United States. “Many people are worried about the damaging effects of cigarette smoke, air pollution and other lung irritants”, said Dr. Dianne Hyson, a registered dietitian and nutrition researcher with the University of California-Davis Medical Center. “This research adds to the growing body of science demonstrating that eating apples may improve health including lung function”. Hyson and her colleagues reported in the February Journal of Medicinal Food that daily consumption of antioxidants in apples and apple juice may help reduce damage caused by oxidation of the “bad” type of cholesterol and protect against heart disease, based on the first human study of its kind involving apples and apple products.

The University of Nottingham study is the fourth recent study to find a positive relationship between apple antioxidants and respiratory health. In January 2000, researchers at London’s St. George’s Hospital documented similar lung function findings in the British journal Thorax, reporting that eating about an apple a day appears to significantly improve lung function. The St. George’s study’s authors also suggested that antioxidant flavonoids such as quercetin – found most abundantly in apples – may be the beneficial mechanism.

Two studies have suggested that apple antioxidants may reduce the risk of lung cancer. In January 2000, University of Hawaii researchers reported in the Journal of the National Canter Institute that increased consumption of quercetin was associated with a reduced risk of lung cancer in their study of 600 lung cancer patients and 600 cancer-free persons. Researchers suggested that quercetin played a protective role by decreasing bio-activation of carcinogens that contribute to lung cancer formation and growth. In 1997, Finnish researchers reported in the American Journal of Epidemiology that intake of antioxidant flavonoids – and especially the apple flavonoid quercetin – appeared to reduce the incidence of lung cancer, based on their 25-year study of 10,000 Finnish men. Researchers suggested that dietary flavonoids might impact cancer by reducing “oxidative stress” on lung tissue, such as the stress caused by smoking.

Dr. Broadfield presented the most recent study’s findings May 20 at the American Thoracic Society’s annual meeting in San Francisco. The research was funded by the British Lung Foundation and the British National Asthma Campaign.