NEW YORK, Mar 08 (Reuters Health) - Most nutritional interventions that have been studied in patients with chronic obstructive pulmonary disease (COPD) appear to be ineffective or inconsistent, according to a review of 21 studies.

Chronic obstructive pulmonary diseases include emphysema and chronic bronchitis. These conditions are marked by a progressive reduction in airflow and are often, though not always, associated with a history of smoking.

Relatively poor nutritional status is common in people with COPD and various programs have been advanced to help these patients gain weight in an effort to reduce breathlessness and improve exercise capacity.

"High-carbohydrate meals were associated with an increase in carbon dioxide production and a decrease in exercise capacity," Dr. Ivone M. Ferreira, of West Park Hospital in Toronto, Ontario, and a multicenter team write in the February issue of Chest. "Short-term...studies in which diets of various compositions were administered supported the notion that high-carbohydrate loads increase the stress on the ventilatory system."

The results of longer-term studies (that is, more than 2 weeks) of nutritional support were inconsistent. Supplementing food with growth hormone or anabolic steroids had no significant effect on exercise capacity.

While, Ferreira's group suggests that a high-fat diet may benefit some COPD patients, they caution that a careful evaluation of these interventions "is hampered by the absence of information regarding body composition, exercise, and health-related quality of life."

Related MEDLINEplus Pages:

• COPD (Chronic Obstructive Pulmonary Disease)