POOR DIET MAY WORSEN LUNG FUNCTION IN COPD PATIENTS

(VANCOUVER, BC, CANADA, November 2, 2010)—A poor diet may be linked to worse lung function in patients with chronic obstructive pulmonary disease (COPD), and new research shows gender may play a role. The study, presented at CHEST 2010, the 76th annual meeting of the American College of Chest Physicians (ACCP), finds that a low dietary intake of certain antioxidants increases the chance of decreased lung function in people with COPD, especially men.

"Our study, along with other research, suggests that strategies for dietary modification and supplementation should be considered in patients with COPD," said M. Salman Khan, DO, Summa Akron City Hospital, part of Summa Health System in Ohio. "Further studies are needed to clarify the role gender has on the loss of lung function in COPD and the impact of antioxidant nutrient intake."

Dr. Khan and colleagues analyzed data from 20 people with COPD (13 women, 7 men) who completed a take-home food frequency questionnaire to assess typical intake of vitamins A, C, D, E, and selenium based on specific foods, portion size, and preparation methods. The researchers compared the nutrient data with nationally recognized dietary reference intakes (DRIs) and classified each person as deficient or not deficient in each nutrient. Each person’s lung function was assessed with the hallmark measurement of FVC, the maximum volume of air exhaled with force.

Results of the analysis showed that a diet poor in antioxidants was common, with the following percentages of participants having deficiencies: 25 percent (selenium), 45 percent (vitamin C), 90 percent (vitamin E), 55 percent (vitamin A), and 70 percent (vitamin D). Decreased lung function was found in all people with a diet deficient in selenium. Of those who were deficient in vitamin C, vitamin A, and vitamin D, lung function was only worse in men.

The role antioxidants played in lung function between male and female subgroups remains unclear. Dr. Khan explains that the difference in lung function between males and females could be attributed to the specific study population.

"The older male population studied may have been exposed to more lifestyle risks than our female population, including, but not limited to, primary or secondhand smoke," said Dr. Khan. "Recurrent lifestyle-related lung injury could deplete the lungs inherent antioxidant capacity, accentuating the role of dietary antioxidants." Furthermore, Dr. Khan explains that there also could be a sex-related difference in the antioxidant function of the lung due to levels of estrogen or testosterone. Women are smaller than men, as well, with proportionately decreased FVCs, so the difference in FVC attributed to antioxidant intake is lesser and more difficult to detect.

The protective role of antioxidants may also extend to people with asthma. Although the pathophysiology of asthma is often different than COPD, there could be a chronic, recurrent, inhalational lung injury component to both diseases.

"We would guess that the role of antioxidant nutrients in a well-controlled asthma patient would be less than that seen in patients with COPD," said Dr. Khan. "However, in patients with severe asthma with poorly controlled symptoms and frequent, recurrent exacerbations, antioxidant nutrient intake may indeed play an important role in the preservation of lung function."

"The results of this study raise questions about the complex mix of genetic, environmental, and nutritional factors at play with the progression of COPD," said David Gutterman, MD, FCCP, President of the American College of Chest Physicians. "Certainly, a proper and balanced diet is not only good for lung health, but for general health."

CHEST 2010 is the 76th annual meeting of the American College of Chest Physicians, held October 30 - November 4 in Vancouver, BC, Canada. The ACCP represents 18,000 members who provide patient care in the areas of pulmonary, critical care, and sleep medicine in the United States and throughout the world. The mission of the ACCP is to promote the prevention, diagnosis, and treatment of chest diseases through education, communication, and research. For more information about the ACCP, please visit the ACCP Web site at www.chestnet.org.