COPDFlavonoids (Soy)

Association between soy and COPD

Researchers from Japan and Australia investigated the relationship between soy consumption and the risk of chronic obstructive pulmonary disease (COPD) and respiratory symptoms.

First, the details.

  • 278 Japanese adults with COPD were compared to 340 adults without COPD.
  • All participants underwent spirometric measurements (volume of air entering and leaving the lungs).
  • Information on demographics, lifestyle characteristics, and habitual food consumption was collected using a questionnaire.

And, the results.

  • Greater soy consumption was correlated with better lung function.
  • There was a significant reduction in the risk of getting COPD among those with the highest total intake of soybean products.
  • Similar decreases in COPD risk were associated with frequent and higher intake of tofu and bean sprouts.
  • Respiratory symptoms (especially breathlessness) were less likely among those with high consumption of soy foods.

The bottom line?
The authors concluded that there’s an “inverse association between soy products and COPD risk for Japanese adults.”

More research is needed to confirm these findings, which are based on the reliability of the participants to accurately record their soy intake. Also, the participants volunteered to participate in the study; therefore, bias can not be ruled out.

Finally, the intake of miso soup and soy sauce was not included in the calculation of total soy intake, because the concentration of miso soup varies substantially according to personal taste, and soy sauce is mainly added during cooking and thus difficult to quantify the exact amount consumed.

7/21/09 20:35 JR

Hi, I’m JR

John Russo, Jr., PharmD, is president of The MedCom Resource, Inc. Previously, he was senior vice president of medical communications at, a complementary and alternative medicine website.