TY - JOUR T1 - Amino acids and asthma: a case-control study JF - European Respiratory Journal JO - Eur Respir J SP - 565 LP - 568 DO - 10.1183/09031936.04.00090404 VL - 23 IS - 4 AU - A. Fogarty AU - E. Broadfield AU - S. Lewis AU - N. Lawson AU - J. Britton Y1 - 2004/04/01 UR - http://erj.ersjournals.com/content/23/4/565.abstract N2 - Amino acids contribute to various anti-oxidant and immunological activities relevant to asthma pathogenesis, raising the possibility that differences in amino acids may be involved in asthma aetiology. The authors hypothesised that cystine reduces the risk of asthma via glutathione metabolism. Methionine, glutamine, glutamic acid and glycine may have potential protective effects, whilst arginine, phenylalanine and tryptophan may have adverse effects in asthma. Fasting plasma levels of amino acids were compared in a case-control study. A total of 89 adults, aged 18–65 yrs, with asthma controlled by inhaled corticosteroids, were recruited from a volunteer database and local primary care registers, and compared with 89 controls individually matched for age, sex and primary care centre. Contrary to the primary hypothesis, cases had higher fasting plasma cystine levels than controls, and there was no difference between cases and controls in any of the other amino acids tested, with the exception of plasma glycine, which was associated with a strongly reduced risk of asthma (odds ratio for the highest tertile compared to lowest 0.30 (95% confidence interval (0.11–0.82)). This study negates the hypothesis that higher fasting plasma cystine levels have a protective effect on the risk of asthma, although the inverse correlation with plasma glycine deserves further investigation. This study was funded by the British Lung Foundation and the University of Nottingham. ER -