Eat Soy to Protect Lungs

Healthnotes Newswire (October 29, 2009)—Chronic obstructive pulmonary disease (COPD) refers to a group of conditions that block airflow in the lungs making it difficult to breathe. COPD worsens over time and can leave a person constantly breathless and fatigued, decrease quality of life, make everyday activities difficult, and lead to disability and dependence.

COPD treatment focuses on controlling symptoms and minimizing further damage, but new research provides hope that something as simple as what you eat every day may play a role in limiting the progressive lung damage associated with COPD. Along with effective treatment, eating well may be the next best way to keep COPD in check.

Soy for easier breathing?

To study the connection between diet and lung function, researchers collected information on nutrition and other health and lifestyle factors from 278 people with, and 340 people without, COPD. Information on smoking, height and weight, age, gender, education level, and alcohol use was collected and analyzed to examine how food choices may affect respiratory symptoms.

The study indicated that people without COPD had significantly higher intake of soy foods, such as tofu and bean sprouts. As well, the results suggest that people who eat the most soy foods have approximately 61% lower likelihood of having COPD compared with people eating the least. As well, higher soy consumption may reduce risk of respiratory symptoms such as breathlessness.

Making sense of soy and COPD

If you have, or are at risk of developing COPD, soy foods may be a good addition to your diet. Keep the following key points in mind when deciding whether soy is for you.

• Regardless of what you eat, the single best way to limit COPD risk is to avoid smoking or to quit if you do smoke.

• The study was conducted in Japan, where people regularly eat a lot of soy foods. People in Japan eat a lot of other foods not regularly eaten in other developed countries, such as seaweed, sea vegetables, and lots of cooked and raw fish. Any one of these other foods also may play a role in protecting lung function.

• The amount of soy consumed by those with better lung function was around 60 grams per day (about 2.2 ounces). A 2.2-ounce piece of tofu would be slightly smaller than a deck of cards.

• This COPD research is a case-control study, which means it cannot prove cause and effect. The study suggests soy may be helpful for protecting lung function, but it does not prove that soy protects lung function.

• Despite the fact that the study cannot prove a cause-and-effect relationship, there aren’t many downsides to adding soy to your diet. If you do want to eat more, choose soy foods, such as tofu, soy milk, edamame (boiled soy beans), and soy nuts, over soy-based supplements such as isoflavones. The study did not suggest that foods fortified with soy or soy-based dietary supplements will protect the lungs.

(Respir Res 2009;10:56)

Suzanne Dixon, MPH, MS, RD, an author, speaker, and internationally recognized expert in chronic disease prevention, epidemiology, and nutrition, has taught medical, nursing, public health, and alternative medicine coursework. She has delivered over 150 invited lectures to health professionals and consumers and is the creator of a nutrition website acclaimed by The New York Times and Time magazine. Suzanne received her training in epidemiology and nutrition at the University of Michigan, School of Public Health at Ann Arbor.

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