Dietary intake of antioxidant (pro)-vitamins, respiratory symptoms and pulmonary function: The MORGEN study

Background--A study was undertaken to investigate the relationships between the intake of the antioxidant (pro)-vitamins C, E and beta-carotene and the presence of respiratory symptoms and lung function. Methods-Complete data were collected in a cross sectional study in a random sample of the Dutch population on 6555 adults during 1994 and 1995, Antioxidant intake was assessed by a semi-quantitative food frequency questionnaire and respiratory symptoms (cough, phlegm, productive cough, wheeze, shortness of breath) were assessed by a self-administered questionnaire, Prevalence odds ratios for symptoms were calculated using logistic regression analysis. Linear regression analysis was used for forced expiratory volume in one second (FEV1) and forced vital capacity (FVC). The results are presented as a comparison between the 90th and 10th percentiles of antioxidant intake. Results--Vitamin C intake was not associated with most symptoms but was inversely related with cough. Subjects with a high intake of vitamin C had a 53 ml (95% CI 23 to 83) higher FEV1 and 79 ml (95% CI 42 to 116) higher FVC than those with a law vitamin C intake. Vitamin E intake showed no association with most symptoms and lung function, but had a positive association with productive cough. The intake of beta-carotene was not associated with most symptoms but had a positive association with wheeze. However, subjects with a high intake of a beta-carotene had a 60 ml (95% CI 31 to 89) higher FEV1 and 75 ml (95% CI 40 to 110) higher FVC than those with a low intake of beta-carotene. Conclusions--The results of this study suggest that a high intake of vitamin C or beta-carotene is protective for FEV1 and FVC compared with a law intake, but not for respiratory symptoms.