Blackmores Institute

Reporting in the American Journal of Epidemiology, the research examined the cohort in the Multi-Ethnic Study of Atherosclerosis (MESA) to determine whether higher circulating levels of docosahexaenoic acid (DHA) were associated with a lower risk of hospitalisation and death due to interstitial lung disease (ILD). “Intratracheal administration of DHA, an omega-3 PUFA, attenuates lung injury and fibrosis in mice, and is associated with better lung function in adults. However, data are lacking on potential associations of DHA and other omega-3 PUFAs with clinical ILD and early lung parenchymal abnormalities detected on imaging in humans,” the authors explained.“We also examined cross-sectional associations between DHA and lung parenchymal abnormalities detected on computed tomography (CT) imaging in MESA, Framingham Heart Study (FHS), and the Age Gene/Environment Susceptibility Reykjavik-Study (AGES).”Results showed that higher DHA plasma phospholipid levels were associated with a lower rate of respiratory hospitalisation with ILD in MESA and was stronger among smokers and higher linoleic acid levels were associated with a higher risk of hospitalisations and death due to ILD in fully adjusted models. A lower prevalence of interstitial lung abnormalities was associated with higher DHA levels in all three cohorts (MESA, FHS, AGES) with DHA more strongly associated with a lower prevalence of interstitial lung abnormalities among smokers compared to never smokers in the AGES cohort. While circulating levels of fatty acids are validated biomarkers of PUFA dietary intake and omega-3 supplementation raises levels of DHA and eicosapentaenoic acid in humans; the study claimed that adults do not adequately meet their daily goal of omega-3 PUFA intake from diet or supplementation, despite recommendations from the World Health Organisation and thus a higher DHA and other omega-3 levels may correlate with healthier lifestyles, possibly driving the link between omega-3s and lower risks of chronic diseases.“Reduced DHA levels may be an indirect marker of lung injury and fibrosis in our study that reflects overall poor health habits that lead to an increased inflammatory and fibrosing state. If DHA was strictly a marker of better health, then we would have expected stronger inverse associations among never smokers as smoking avoidance is strongly linked to a healthy lifestyle,” the authors said.“Alternatively, our findings may be driven by a biological protective effect of DHA (and other omega-3s). Protectins, resolvins, and maresins are pro-resolving lipid mediators derived from DHA and eicosapentaenoic acid and are critical in resolving lung inflammation by inhibiting neutrophil chemotaxis and activation and trafficking of lymphocytes and macrophages.”“Higher circulating levels of DHA were associated with a lower rate of clinical ILD events prospectively and less lung abnormalities on CT cross-sectionally among adults. Further studies that examine downstream biological pathways of omega-3s and their metabolites in adults with lung imaging abnormalities and clinically diagnosed ILD through several platforms (i.e. transcriptomics, proteomics) will provide insight on causality and mechanisms between omega-3s and ILD,” the authors concluded.
 
 Source:
 American Journal of Epidemiology. 2020. DOI: <a href="https://doi.org/10.1093/aje/kwaa168 " target="_blank">10.1093/aje/kwaa168</a>

New research has found omega-3 fatty acids can reduce the prospective rate of clinical interstitial lung disease events and lung abnormalities.

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