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.

Long-term weekly iron supplementation improves and sustains nonpregnant women's iron status as well or better than currently recommended short-term daily supplementation.

This 7-mo double-blind study compared the efficacy of two iron supplementation schemes in improving iron nutrition among 116 healthy fertile-age women. They were randomly distributed in three groups, receiving: Group 1, iron + folate (60 mg and 250 microg, respectively) daily for 3 mo (currently recommended scheme), and folate (250 microg) weekly the subsequent 4 mo. Group 2, folate daily, and 60 mg iron only once weekly for 3 mo, and then weekly iron + folate for 4 mo. Group 3, folate daily for 3 mo and then weekly for 4 mo. At baseline, 16% had depleted stores (plasma ferritin <15 microg/L) and 16% had hemoglobin levels <125 g/L. Eight percent had hemoglobin levels <120 g/L. In Group 1 hemoglobin and ferritin increased at 3 mo but returned to near basal conditions after 4 mo of weekly folate. In Group 2, hemoglobin and ferritin increased progressively throughout the 7 mo but mostly after 3 mo. Group 3 did not change. Side effects were highest with daily iron. Weekly iron supplementation over 7 mo (30 doses) improved and sustained iron nutrition at least as effectively and was better tolerated than 90 daily iron supplements consumed during 3 mo.