The differential effects of eicosapentaenoic acid and docosahexaenoic acid on cardiovascular risk factors: an updated systematic review of randomized controlled trials
What this study found
EPA and DHA both improved several cardiovascular risk factors, but their effects were not identical. Both lowered triglycerides, with DHA likely producing a slightly greater reduction, and both increased HDL2 cholesterol, again with a larger increase seen with DHA. DHA may also raise LDL cholesterol and LDL particle size, and it appeared more effective than EPA for lowering heart rate and blood pressure in several comparisons. Both fatty acids affected inflammation, platelet function, and oxidative stress, with DHA showing stronger anti-inflammatory effects in some trials, while effects on…
- Study & population
- Updated systematic review of randomized controlled trials in adults.
- Intervention
- Randomized trials compared pure or near-pure eicosapentaenoic acid (EPA) versus docosahexaenoic acid (DHA), generally at doses of at least 2 g/day and given orally for several weeks to years.
- Key limitation
- The evidence base was limited by a small number of direct EPA versus DHA head-to-head trials and generally short study durations.
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Open PDFOriginal abstract
Cardiovascular disease remains a major global health concern. The combination of the omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) has been shown to beneficially modify a range of cardiovascular risk factors. However, whether EPA and DHA have differential effects or potencies is currently unclear. A systematic review of randomized controlled trials (RCTs) that compared ≥2 g/day of near pure EPA and DHA was conducted. A total of 24 publications from nine unique RCTs were included. EPA and DHA both lower triglyceride levels, with DHA most likely having a slightly greater effect. Furthermore, both EPA and DHA increase high density lipoprotein (HDL) 2 cholesterol, which is cardioprotective, with the increase being greater with DHA. DHA appears to increase low density lipoprotein (LDL) cholesterol; however, DHA also increases LDL particle size, which would render LDL less atherogenic. DHA seems more effective than EPA in decreasing heart rate and blood pressure. Both EPA and DHA alter platelet function decreasing thrombogenicity, although they may have different actions on platelets. Both EPA and DHA decrease F2-isoprostanes, interpreted as a reduction in oxidative stress. They both decrease inflammatory gene expression and promote an anti-inflammatory oxylipin profile. These are all favorable effects with regard to cardiovascular disease risk. Effects of EPA and DHA on blood glucose are inconsistent. This review is constrained by the small number of high quality RCTs that directly compare EPA to DHA and report on outcomes other than blood lipids. There is a need for additional high-quality research to assess the independent effects of EPA and DHA on cardiovascular risk factors (e.g., inflammation, blood pressure, vascular function, platelet function) in larger and more diverse study populations.