Dietary antioxidants and asthma in adults. Issue 5 (7th February 2006)

• Record Type: Journal Article
• Authors: Patel, B D; Welch, A A; Bingham, S A; Luben, R N; Day, N E; Khaw, K-T; Lomas, D A; Wareham, N J
• Is Part Of: Thorax. Volume 61:Issue 5(2006)
• Page Start: 388
• Page End: 393
• Publication Date: 2006-02-07
• Subjects: BMI, body mass index -- FEV1, forced expiratory volume in 1 second -- FVC, forced vital capacity -- HLQ, health and lifestyle questionnaire -- NRHS, Norfolk respiratory health survey; antioxidants -- asthma -- diet -- epidemiology; Chest -- Diseases -- Periodicals; Thorax; Chest -- Diseases; Periodicals; Periodicals; 617.54
• DOI: 10.1136/thx.2004.024935
• Languages: English
• ISSNs: 0040-6376

Abstract

Abstract : Background: Several antioxidant nutrients have been reported to be inversely associated with asthma. A study was undertaken to assess the independent associations of these nutrients with asthma in adults. Methods: A nested case-control study was performed in 515 adults with physician diagnosed asthma and 515 matched controls using dietary data obtained from 7 day food diaries. The main outcome measures were physician diagnosed asthma and current symptomatic asthma (diagnosed asthma and self-reported wheeze within the previous 12 months). Results: Cases were similar to controls in age, sex, social class, and daily energy intake but had a lower median intake of fruit (132.1 v 149.1 g/day, p⩽0.05). 51.5% of the population reported zero consumption of citrus fruit; relative to these individuals, people who consumed >46.3 g/day had a reduced risk of diagnosed and symptomatic asthma (OR adjusted for potential confounders 0.59 (95% CI 0.43 to 0.82) and 0.51 (95% CI 0.33 to 0.79), respectively). In nutrient analysis, dietary vitamin C and manganese were inversely and independently associated with symptomatic asthma (adjusted OR per quintile increase 0.88 (95% CI 0.77 to 1.00) for vitamin C and 0.85 (95% CI 0.74 to 0.98) for manganese), but only manganese was independently associated with diagnosed asthma (OR 0.86 (95% CI 0.77 to 0.95)). Adjusted plasma levels of vitamin C were significantly lower in symptomatic cases than in controls (54.3 v 58.2 μmol/l, p = 0.003). Conclusions: Symptomatic asthma in adults is associated with a low dietary intake of fruit, the antioxidant nutrients vitamin C and manganese, and low plasma vitamin C levels. These findings suggest that diet may be a potentially modifiable risk factor for the development of asthma.