The role of nutritional factors in exercise-induced bronchoconstriction: a narrative review

Exercise-induced bronchoconstriction (EIB) describes an acute narrowing of the airways that develops following vigorous physical activity. Clinical responses to current asthma therapy, such as leukotriene antagonists and corticosteroids, are heterogeneous, even with optimal treatment. Epidemiological studies indicate an increasing use of complementary and alternative medicine therapy in asthma patients due to the lack of efficacy of conventional treatment, concerns about potentially harmful side effects of pharmacological treatment, cost barriers to asthma care, and the accessibility of complementary and alternative medicine therapy. Plausible physiological mechanisms now exist for many nutrients as potential modifiers of EIB severity, primarily because of their role in inflammatory processes, airway smooth muscle function, and modulation of lung microvascular volume and pressure. Dietary supplementation as a treatment for EIB has generally shown evidence of significant yet incomplete inhibition of EIB with low-salt diets, omega-3 fatty acids, and vitamin C when supplemented for up to 3 weeks. However, larger, randomized, placebo-controlled, double-blinded trials are needed to clarify the effectiveness of nutritional intervention in individuals with EIB. Additionally, many studies have focused on nonathletes with EIB, and therefore, more studies are required to evaluate the efficacy of nutritional intervention on EIB in elite athletes. In conclusion, if dietary supplementation or restriction is prescribed, it should be seen as an option to lessen the reliance on pharmaceutical interventions and not as an alternative to established pharmacotherapies.