Antioxidant vitamin supplementation in asthma.
The influence of nutrition on chronic bronchial asthma has an important place in the management of this disease. Evidence suggests that specific inflammatory abnormalities exist in the airways of subjects suffering from mild-to-moderate persistent asthma, in whom an inflammatory state is often associated with increased generation of reactive oxygen species and the damaging effects of free radicals. For this reason oxidant stress may be an important pathogenic factor in the progress of the disease. The role of nutrition in bronchial asthma is related to antioxidant vitamins A, C, and E. By counteracting oxidants and reducing external attacks (bacteria, virus, toxins, xenobiotics) in the lung, antioxidant vitamins modulate the development of asthma and the impairment of pulmonary function. Dietary studies suggest relations between oxidative stress, bronchial inflammation, development of asthmatic symptoms, and reduction of cellular functions. Dietary interventions may reduce oxidant stress and prevent or minimize asthmatic symptoms. Such interventions may provide a cost-effective approach to asthma management that may supplement current pharmacological strategies, although this conclusion is not supported by many randomized, placebo-controlled studies. The aim of this short review is to summarize current knowledge regarding the relations between antioxidant vitamins and the treatment of bronchial asthma.