Background Emerging evidence suggests that fatty acid supplementation has a direct effect on the inflammatory cascade, with recently discovered pro-resolving lipid mediators inducing anti-inflammatory mechanisms in animal studies. We aimed to conduct a systematic review to investigate the relationship between omega-3 fatty acid supplementation and respiratory outcomes in adult patients with asthma compared to non-supplementation.

Methods We identified randomised controlled studies of fatty acid supplementation in adults with asthma through a systematic review of the databases Pubmed, Medline, Embase, CINAHL. Returned Results were screened, quality assessed and cross-checked according to the study inclusion criteria by two researchers.

Results The search found seven high quality studies in the literature suitable for inclusion in the review. Four studies did not show a significant difference in FEV1 between intervention and control groups. Two studies showed an improvement with bronchodilator use, two did not. Three studies showed improvement in Asthma symptoms compared to two studies of no benefit. Two studies showed improvement in peak flow, whereas two did not. Small patient numbers recruited in the studies, differences in fatty acid supplementation at different dosages and lack of published studies limit the strength of evidence presented.

Conclusion There is no significant evidence to suggest supplementation with fatty acids improve pulmonary function in adult patients with Asthma. Evidence for improvement in symptom control is unequivocal. Much of the data is from small short duration studies. Larger studies are required, with non-biologically active control, In the future to evaluate clinical correlation between supplementation and effect on asthma control.