The relation between dietary intake of individual fatty acids, FEV1 and respiratory disease in Dutch adults
- 1 University of Nottingham, Nottingham, UK
- 2 Cornell University, New York, USA
- 3 National Institute of Public Health and the Environment, The Netherlands
- 4 Imperial College London, London, UK
- Dr T M McKeever, University of Nottingham, Clinical Science Building, City Hospital, Nottingham NG5 1PB, UK;
- Received 11 September 2007
- Accepted 13 September 2007
- Published Online First 27 September 2007
Background: A reduced dietary intake of n-3 fatty acids, in association with increased n-6 fatty acid intake, has been proposed as a potential aetiological factor for chronic obstructive pulmonary disease (COPD) and asthma. However, the relative importance of individual fatty acids within the n-3 and n-6 categories on this effect has not been widely investigated. We have studied the relation between individual fatty acid intakes, lung function and self-reported respiratory symptoms and diagnoses in a representative sample of more than 13 000 Dutch adults.
Methods: Intake of individual fatty acids was estimated by a food frequency questionnaire and analysed in relation to measures of forced expiratory volume in 1 s (FEV1) and to questionnaire reported wheeze, asthma and COPD symptoms.
Results: After adjusting for confounding, we found no protective association between individual n-3 fatty acid intakes and FEV1. Higher intakes of some n-6 fatty acids were associated with lower FEV1, this effect being most marked for c22:4 n-6 docosatetraenoic acid (reduction in FEV1 between the highest and lowest quintile of intake 54.5 ml (95% CI −81.6 to −27.4)). Most of the n-6 fatty acid effects interacted significantly with smoking, their effects being strongest in current smokers. Individual n-3 fatty acid intakes were generally associated with a higher risk of wheeze in the past year, but otherwise there was little or no association between fatty acid intake and wheeze, doctor diagnosed asthma or other respiratory symptoms.
Conclusions: A high intake of n-3 fatty acids does not appear to protect against COPD or asthma, but a high intake of several n-6 fatty acids is associated with a significant reduction in FEV1, particularly in smokers. These findings indicate that high dietary intake of n-6 fatty acids, rather than reduced n-3 intake, may have an adverse effect on lung health.
Funding: Funded by the Wellcome Trust, Ministry of Public Health, Welfare and Sport of The Netherlands, and by the Institute of Public Health and the Environment.
Competing interests: None.
Ethics approval: Data collection for this research was approved by the Dutch Medical Ethics Committee.