Title: Legume and Soy Consumption May Improve COPD Symptoms: New Study Findings

Consuming legumes and soy-based foods may help improve symptoms of chronic obstructive pulmonary disease (COPD) by reducing inflammation and irritation, according to a new study published in the March 2026 issue of Chronic Obstructive Pulmonary Diseases: Journal of the COPD Foundation.

The study, led by Daniel C. Belz, M.D., MPH, of the Division of Pulmonary and Critical Care Medicine at Johns Hopkins University in Baltimore, examined the impact of isoflavone consumption on breathing symptoms, cough, and overall lung health in former smokers with COPD.

Isoflavones, a natural compound commonly found in legumes and soy-based foods, were associated with fewer breathing-related symptoms, including reduced coughing and less difficulty clearing mucus, among participants with higher intake.

Participants completed dietary questionnaires and underwent lung function tests and clinical assessments at baseline, three months, and six months. Isoflavone consumption was calculated as the average intake across available visits.

Results showed that individuals with higher isoflavone consumption experienced improved lung health and fewer respiratory symptoms compared to those with lower intake.

Previous research supports these findings, including a case-control study in Japan that reported soy foods may reduce the development of chronic respiratory conditions, and another study linking soy consumption to better lung function and reduced risk of respiratory problems.

COPD, which includes emphysema and chronic bronchitis, is a progressive inflammatory lung disease affecting more than 30 million Americans and is the fourth leading cause of death worldwide.

Diet and nutrition have been identified as modifiable risk factors for chronic lung diseases like COPD, making nutritional interventions a promising area for symptom management.

While the study highlights a potential benefit of isoflavone-rich foods, researchers emphasize the need for further investigation to determine which specific nutritional components are responsible for reducing inflammation in conditions like COPD.