Anti-inflammatory effects of DHA compared to EPA.
Sub-clinical inflammation is recognised as a key factor in the development of atherosclerosis and progression to ischaemic heart disease. Whilst there is a growing body of research suggesting long chain [omega]-3 (n-3) polyunsaturated fatty acids (PUFAs) may reduce the proinflammatory state associated with obesity and metabolic syndrome, most studies investigating the anti-inflammatory effects have used varying combinations of eicosapentanoic acid (EPA) and docohexaenoic acid (DHA). The current study aimed to compare the individual effects of EPA supplementation with DHA supplementation on inflammatory markers and blood lipids in men and women at risk of cardiovascular disease (CVD).
The Canadian trial was a double-blind, randomised, crossover, controlled study conducted in individuals with abdominal obesity ([greater than or equal to] 80 cm for women, [greater than or equal to]94 cm for men) and subclinical inflammation (>1-<10 mg/L plasma CRP). Subjects were to be otherwise healthy and were recruited via media. There were three treatment phases in the study: 1) EPA 2.7g/day, 2) DHA 2.7g/day, and 3) corn oil (0g EPA and 0g DHA) as a control; with each treatment phase having a median duration of 10 weeks and a washout period between treatments of 9 weeks. Participants were instructed to maintain a constant body weight over the study period, and received dietary counselling and instructions to exclude fatty fish, fishoil supplementation, flax products, walnuts, and n-3-enriched products through the three study phases. Primary analyses assessed the difference in cardiometabolic outcomes between EPA and DHA groups, including plasma C-reactive protein (CRP), interleukin (IL)-6, IL-18, tumour necrosis factor (TNF)-[alpha], and adiponectin. Secondary outcomes assessed were blood lipid profiles including total cholesterol (TC), LDL cholesterol, HDL cholesterol, triglycerides (TG), and apolipoprotein B (apoB).
From the 154 subjects randomised, the dropout rate of the study was 20%. The completion rate varied by intervention phase due to the randomised, crossover nature of the study. The final analysis [DELTA]DHA (DHA compared with control) was based on n = 123, and the analysis of AEPA was based on n = 121. Compared with the EPA treatment, supplementation with DHA led to a greater reduction in serum IL-18 and a greater increase in adiponectin. Changes in CRP and TNF-[alpha] were not significantly different between DHA and EPA treatments. Compared to control, EPA significantly deceased plasma IL-6 only, whilst DHA significantly decreased CRP, IL-6, IL-18, and TNF-[alpha], and increased adiponectin concentrations compared to control. Regarding the lipid profiles, supplementation with DHA significantly reduced TGs and the TC:HDL ratio, and increased LDL and HDL cholesterol concentrations, when compared to EPA supplementation. A sex interaction was noted for the increase in LDL for the DHA supplementation, with a greater increase in men but not in women when compared to EPA. No significant differences were observed for either group with apoB concentrations.
Authors report this to be the first study designed specifically to provide a head-to-head comparison of the effects of EPA and DHA on inflammation as a primary outcome in men and women, and accordingly, the study provides good insight into some differences of effect of the different PUFAs. The increase of LDL observed deserves further investigation, with authors suggesting that interpretation of the overall results could suggest an increase in LDL particle size, which should be a focus of future studies. Authors concluded that DHA is more effective than EPA in modulating specific markers of inflammation, as well as blood lipids. More studies to determine the effects on CVD risk and outcomes, as well as further investigation into the effects of EPA and DHA on lipid particle size are required.
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|Title Annotation:||docohexaenoic acid; eicosapentanoic acid|
|Publication:||Australian Journal of Herbal Medicine|
|Date:||Sep 1, 2016|
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