Watching Salt Intake Won’t Shake Asthma

Low-Sodium Diet Doesn’t Improve Asthma Symptoms, New Study Shows

Medically Reviewed by Louise Chang, MD on July 15, 2008
From the WebMD Archives

July 15, 2008 -- Cutting back on salt and following a low-sodium diet isn't likely to improve asthma symptoms, according to a new study.

Previous studies had suggested that following a low-sodium diet may help improve asthma control, but researchers now say that advice should be taken with a grain of salt.

"We were disappointed that a simple measure, such as a decrease in sodium intake, does not result in improvements in asthma control," researcher Zara E. K. Pogson, MRCP, clinical research fellow at the University of Nottingham in England, says in a news release. "We therefore cannot advise people with asthma to alter their sodium intake to better control their asthma, despite the fact that a low-sodium diet improves cardiovascular risk factors."

Diet and Asthma Control

Researchers say prior studies on low-sodium diets and asthma control have produced inconsistent results or were too small.

In this study, published in the American Journal of Respiratory and Critical Care Medicine, researchers compared the effects of a low-sodium vs. normal-sodium diet on asthma control in nearly 200 adults with asthma for six weeks. All of the participants followed a strict low-sodium diet and either received sodium supplements equivalent to normal sodium intake or a placebo.

After six weeks, researchers measured control of asthma symptoms and lung function and found no significant differences between the two groups despite the difference in sodium intake.

Researchers say the results suggest that a low-sodium diet provides no additional benefits in improving asthma control.

"This study suggests that further dietary research in asthma should be directed to factors other than sodium," Pogson says.

Show Sources


Pogson, Z. American Journal of Respiratory and Critical Care Medicine, July 2008; vol 178: pp 132-138.

News release, American Thoracic Society.

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