Improved lung function following dietary antioxidant supplementation in exercise-induced asthmatics

Area of Science:

• Exercise physiology
• Pulmonary medicine
• Nutritional science

Background:

• Oxidative stress is a key factor in exercise-induced asthma (EIA).
• Antioxidant supplementation may help reduce EIA symptoms.
• Ascorbic acid (AsA) and alpha-tocopherol are potent antioxidants.

Purpose of the Study:

• To investigate the effects of AsA and alpha-tocopherol supplementation on airway function in EIA subjects.
• To determine if antioxidant supplementation can improve pulmonary function post-exercise.

Main Methods:

• Single-blind randomized crossover study with EIA subjects and healthy controls.
• Participants received either vitamin (AsA 500 mg; alpha-tocopherol 300 IU) or placebo daily for three weeks, followed by a washout period.
• Pulmonary function tests (FVC, FEV1, FEF25-75%, PEFR) were conducted pre- and post-exercise (treadmill test at 90% VO2peak).

Main Results:

• Supplementation significantly improved forced vital capacity (FVC) at 5 and 15 minutes post-exercise.
• Improvements in forced expiratory volume in one second (FEV1) and forced expiratory flow between 25% and 75% (FEF25-75%) were observed at 5, 15, and 30 minutes post-exercise.
• Peak expiratory flow rate (PEFR) also showed significant improvement at 5 and 15 minutes post-exercise.

Conclusions:

• Ascorbic acid and alpha-tocopherol supplementation may support pulmonary function recovery in individuals with EIA.
• Antioxidant therapy shows promise for managing exercise-induced asthma.
• Further research is warranted to confirm these findings and optimize dosage.