Effect of Fish Oil and Vitamin C on Exercise-Induced Bronchoconstriction and Airway Inflammation in Asthma

The aim of this study is to extend previous findings that nutritional supplementation or dietary modification can ameliorate exercise-induced bronchoconstriction. It has been shown in separate studies that fish oil and ascorbic acid (vitamin C) individually protect against EIB by improving pulmonary function and reducing airway inflammation. The main aim of this study is to determine the comparative and additive effects of fish oil and ascorbic acid supplementation on EIB and airway inflammation in asthmatic individuals.

Inclusion criteria

• Diagnosis of asthma, based on medication use as well as history and symptoms as outlined in the NHLBI Guidelines for the Diagnosis and Management of Asthma
• Diagnosis of EIB, based on ≥10% fall in post-challenge FEV1, a measure of lung function, after dry air eucapnic voluntary hyperventilation (EVH), a simulated exercise challenge
• Not currently taking asthma maintenance medication or physician approval to discontinue current asthma medication for the duration of the study
• Not currently taking any fish oil or ascorbic acid supplements above the level recommended for adequate intake (if currently taking supplements, can participate if the subject stops taking the supplements for 2 weeks before starting the study and throughout the study)
• Agree to limit fish consumption to 1 fish meal per week throughout the study
• Agree to avoid vitamin C-rich foods throughout the study

Exclusion criteria

• Resting FEV1 (the amount of air blown out in the first second of a forced exhalation) <60% of predicted when off medication
• Pregnancy
• History of cardiovascular disease, including hyperlipidemia (high cholesterol) and hypertension (high blood pressure)
• History of bleeding disorders or delayed clotting time
• History of diabetes
• History of seizures
• Allergy to fish oil or ascorbic acid (vitamin C)