Antioxidant intake, GSTM1 polymorphism and pulmonary function in healthy young adults.

Dietary antioxidants may protect lung tissue against reactive oxygen species-induced injury, adverse respiratory effects and reduced pulmonary function. Genetic variability in antioxidant enzymes also determines response to oxidative stress in the lung. The current authors evaluated whether lung function levels are associated with dietary intake of antioxidants and the glutathione S-transferase M1 (GSTM1) polymorphism. The current study cohort consisted of healthy, nonsmoking freshmen students who were lifetime residents in the Los Angeles or the San Francisco Bay areas (CA, USA). Participants completed comprehensive residential history, health history and food frequency questionnaires. Blood for genotyping was collected and forced expiratory volume measurements were obtained. Dietary vitamin C, magnesium and daily fruit servings were associated positively with forced expiratory volume in one second in males and with maximum mid-expiratory flow, forced expiratory flow after 75% of expelled volume, and the ratio of maximum mid-expiratory flow to forced vital capacity in females. In multivariable regression, vitamin C (or fruit for male students) and magnesium showed a consistent, positive association with lung function. Among healthy female adolescents, dietary intake of vitamin C is associated with increased levels of lung function. The current study does not support a role for the glutathione S-transferase M1-null genotype as an independent risk factor for decrements in lung function.