Fish Oil May Help Reduce Exercise-Induced Asthma Symptoms

The research showed that the special diet with added fish oil reduced narrowing of the patient's airway and enabled the person to use less asthma medication. These findings, in combination with related research findings by exercise physiologist Timothy D. Mickleborough, show the possible benefits of combining dietary supplementation with reduced medication. A combination of these into a treatment could be at least as beneficial as either in isolation. There would also be fewer of the potential side effects from medication, such as reduced effectiveness from long-term use and toxicity from some medications.

"There have been remarkable advances in asthma therapy over the last 10 years. Inhaled corticosteroids and short-acting beta-2-agonists have proven to be highly effective. Long-acting beta-2-agonists have facilitated the control of asthma, and daily medications such as leukotriene modifiers have recently proven highly effective in asthma therapy. However, these medications are not without real and potential side effects," said Mickleborough, assistant professor in the Department of Kinesiology at IU Bloomington. "Alternative therapies for EIA, or therapies that reduce the dose requirements of traditional medications, would be of benefit to the asthmatic and potentially reduce the public health burden of this disease."

Exercise-Induced Asthma
In exercise-induced asthma (EIA) breathing becomes difficult due an acute narrowing of the airway after exercise triggered by vigorous exercise. Around 80 percent of people with asthma have this condition, also called exercise-induced bronchoconstriction. EIA also is found in an estimated 10 percent or more of elite athletes and as much as 10 percent of the general population without asthma. EIA can discourage people, particularly children, from participating in sports and other physical activity.

"Exercise is a powerful trigger for asthma symptoms, so young individuals may avoid vigorous activity, resulting in damaging consequences to their physical and social well-being," Mickleborough said.

Research Results
The study’s participants were adults with mild to moderate persistent asthma. In the study, the post-exercise lung function of participants improved by about 64 percent and their use of emergency inhalers decreased by 31 percent when they consumed a diet supplemented with fish oil, rich in omega-3 polyunsaturated fatty acids (n-3 PUFA), for three weeks.

The typical diet for people in Western societies includes 20 to 25 times more n-6 polyunsaturated fatty acids (found in sunflower, safflower, and corn oils among others) than n-3 PUFA (also found in canola and flaxseed oils, along with fish oil). The Western diet is also considered pro-inflammatory.

Key Research Findings
One of the key findings from the study was that, while on the diet supplemented daily with fish oil (3.2 grams of eicosapentaenoic acid and 2 grams of docohexaenoic acid), airway pro-inflammatory cells and markers, which are responsible for airway inflammation and subsequent airway obstruction, were reduced in sputum taken from the EIA subjects.

The randomized, double-blind cross-over study involved 16 people with mild-to-moderate persistent asthma, meaning they required daily maintenance medications to control their symptoms. The study participants did not use their maintenance medication during the course of the study and were all considered recreationally active. The fish oil was pharmaceutical grade, meaning it was purified at a molecular level to remove metals and other harmful contaminants that can be present in retail fish oil products.

Co-authors of the report include Martin Lindley, research scientist in the IUB Department of Kinesiology; Alyce Fly, associate professor in the IUB Department of Applied Health Science; and Alina Ionescu, Department of Respiratory Medicine, University of Wales College of Medicine, Cardiff, UK.

Studies on the impact of diet on EIA are limited and inconclusive. Research by Mickleborough and his colleagues has provided the most complete picture to date of the impact fish oil and low-salt diets can have on exercise-induced asthma.

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