Antioxidant Nutrients and Pulmonary Function: The Third National Health and Nutrition Examination Survey (NHANES III)

Abstract

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.

Lung function and blood levels of copper, selenium, vitamin C and vitamin E in the general population

“…In the three studies where comparable data of the absolute effect of a change in plasma/serum vitamin C on the association with FEV 1 is available, the size of effect in our study of 69 ml per mg/dl vitamin C was comparable to that reported by Hu et al from the USA (41.5 ml per mg/dl vitamin C), but less than data from Kelly et al, collected in Scotland (154 ml per mg/dl plasma vitamin C). The absence of evidence of effect modification by smoking status was also consistent with previous similar studies (Ness et al, 1996;Hu & Cassano, 2000;Schunemann et al, 2001), although the study was too underpowered to detect a difference between smokers and nonsmokers.…”

“…An association between plasma vitamin C and lung function has also been demonstrated in several other studies (Ness et al, 1996;Hu & Cassano, 2000;Schunemann et al, 2001;Kelly et al, 2003) and is consistent with the hypothesis that increased antioxidant status protects the lungs against loss of lung function. The protective effect of plasma vitamin C on lung function of 49 ml per s.d.…”

“…increase, equated to the equivalent of between 1 to 2 y of ageing (Fletcher et al, 1976), is also consistent with the existing literature, which demonstrates a range of 28-78 ml increase in FEV 1 per s.d. increase in plasma vitamin C (Ness et al, 1996;Hu & Cassano, 2000;Schunemann et al, 2001;Kelly et al, 2003). In the three studies where comparable data of the absolute effect of a change in plasma/serum vitamin C on the association with FEV 1 is available, the size of effect in our study of 69 ml per mg/dl vitamin C was comparable to that reported by Hu et al from the USA (41.5 ml per mg/dl vitamin C), but less than data from Kelly et al, collected in Scotland (154 ml per mg/dl plasma vitamin C).…”

“…Copper is also necessary in the diet to prevent inflammation (Denko, 1979) and emphysema in animal models (O'Dell et al, 1978), as well as reducing the adverse effects of maternal nicotine exposure on lung development in rats (Maritz & Windvogel, 2003), and so may also have a protective effect against COPD. Previous epidemiological studies have provided evidence supporting a protective effect of selenium on lung function (Hu & Cassano, 2000), but data on copper are much more limited (Sparrow et al, 1982). We have investigated the relation between serum copper, selenium, vitamin C and E with lung function in a randomly selected crosssectional population of adults from the United Kingdom.…”

Antioxidants in cystic fibrosis☆Conclusions from the CF Antioxidant Workshop, Bethesda, Maryland, November 11-12, 2003

“…Higher plasma levels of Se are associated with decreased risk of asthma [171] and with higher FEV 1 , particularly in the face of chronic oxidative stress caused by active or passive exposure to cigarette smoke [172]. Selenium supplementation has been associated with a reduction in cancer risk [173].…”