Dietary components with demonstrated effectiveness in decreasing the severity of exercise-induced asthma.

Exercise-induced asthma (EIA) occurs in up to 90% of individuals with asthma and approximately 10% of the general population without asthma. EIA describes a condition in which vigorous physical activity triggers acute airway narrowing with heightened airway reactivity resulting in reductions in forced expiratory volume in 1 second of greater than 10% compared with pre-exercise values. Treatment of EIA almost exclusively involves the use of pharmacological medications. However, there is accumulating evidence that a dietary excess of salt and omega-6 fatty acids, and a dietary deficiency of antioxidant vitamins and omega-3 fatty acids, can modify the severity of EIA. The modification of these dietary factors has the potential to reduce the incidence and prevalence of this disease. The dietary component most studied to date is dietary salt. Recent studies have supported a role for dietary salt as a modifier of the severity of EIA, suggesting that salt-restrictive diets can reduce the severity of EIA. Since EIA is part of the asthmatic diathesis, it is possible that EIA may serve as a useful model for investigation of potential dietary interventions for reducing airway hyperresponsiveness.