Antioxidants, oxidative stress, and pulmonary function in individuals diagnosed with asthma or COPD

Objective: The objective of this study was to investigate the association between antioxidant nutrients and markers of oxidative stress with pulmonary function in persons with chronic airflow limitation. Design: Cross-sectional study exploring the association of antioxidant nutrients and markers of oxidative stress with forced expiratory volume in the first second (FEV₁%) and forced vital capacity (FVC%). Setting/Subjects: The study data included 218 persons with chronic airf low limitation recruited randomly from the general population of Erie and Niagara counties, New York State, USA. Results: After adjustment for covariates, multiple linear regression analysis showed that serum β-cryptoxanthin, lutein/zeaxanthin, and retinol, and dietary β-carotene, β-cryptoxanthin, lutein/ zeaxanthin, vitamin C, and lycopene were positively associated with FEV₁% (P<0.05, all associations). Serum vitamins β-cryptoxanthin, lutein/zeaxanthin, and lycopene, and dietary β-cryptoxanthin, β-carotene, vitamin C, and lutein/zeaxanthin were positively associated with FVC% (P<0.05, all associations). Erythrocytic glutathione was negatively associated with FEV₁ %, while plasma thiobarbituric acid-reactive substances (TBARS) were negatively associated with FVC% (P<0.05). Conclusion: These results support the hypothesis that an imbalance in antioxidant/oxidant status is associated with chronic airflow limitation, and that dietary habits and/or oxidative stress play contributing roles.