beta-carotene and Lung-Diseases--Obstructive

Recent studies of chronic obstructive pulmonary disease have raised interest in its relation to nutrition. Several dietary antioxidants have been positively associated with lung function in healthy, general population samples. This study considered the separate and joint effects of vitamin C, vitamin E, beta-carotene, and selenium intake and used both dietary assessment and serum biomarkers of antioxidant status. The authors used data from the Third National Health and Nutrition Examination Survey comprising a sample representative of the US population in 1988-1994 (n = 18,162 subjects aged > or =17 years). Multiple linear regression analysis examined the separate and joint effects of the antioxidants on the ratio of forced expiratory volume in the first second (FEV1)/height2 adjusted for covariates. Each of the dietary and serum antioxidant nutrients was significantly associated with FEV1. When they were considered simultaneously (dietary and serum variables considered in separate models), independent associations were observed for most nutrients. Serum beta-carotene was less positively associated with FEV1 in smokers than nonsmokers, while serum selenium had a stronger positive association with FEV1 in smokers. The authors found that higher levels of antioxidant nutrients are associated with better lung function. The finding that the antioxidants differ in both their overall association with lung function and in whether this association varies by smoking status has implications for further research.

Topics: Adult; Antioxidants; Ascorbic Acid; beta Carotene; Diet; Female; Forced Expiratory Volume; Humans; Linear Models; Lung Diseases, Obstructive; Male; Middle Aged; Nutrition Assessment; Nutrition Surveys; Predictive Value of Tests; Selenium; Smoking; Spirometry; Surveys and Questionnaires; United States; Vitamin E

The effects of alpha-tocopherol (50 mg/d) and beta-carotene (20 mg/d) supplementation on symptoms of chronic obstructive pulmonary disease were studied among the 29,133 participants of the Alpha-Tocopherol Beta-Carotene Cancer Prevention Study undertaken to investigate the effects of these two substances in the prevention of lung and other cancers. During the follow-up the supplementations did not affect the recurrence or incidence of chronic cough, phlegm, or dyspnea. The prevalence of chronic bronchitis and dyspnea at baseline was lower among those with high dietary intake of beta-carotene (OR = 0.78 and 0.67, respectively) or vitamin E (OR = 0.87 and 0.77) and high serum beta-carotene (OR = 0.59 and 0.62) and alpha-tocopherol (OR = 0.76 and 0.82). High intake and serum levels of retinol were associated with low prevalence of dyspnea (OR = 0.84 and 0.80, respectively) but not with chronic bronchitis. The results indicate no benefit from supplementation with alpha-tocopherol or beta-carotene on the symptoms of chronic obstructive pulmonary disorders but support the beneficial effect of dietary intake of fruits and vegetables rich in these compounds.

Topics: Aged; Antioxidants; beta Carotene; Bronchitis; Cough; Dietary Supplements; Dyspnea; Humans; Lung Diseases, Obstructive; Male; Middle Aged; Vitamin A; Vitamin E