Increased EPA Blood Levels Seen With DHA Supplementation

There are a multitude of studies demonstrating the benefit of the combined essential fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) on cardiovascular disease (CVD) markers. A paper by Kelley et al focused on the benefits delivered by supplemental DHA and its sole influence on CVD markers in hypertriglyceridemic men.

Subjects received either 7.5g/d of DHA oil (3g DHA/d) or an olive oil placebo for 90 days. Fasting blood levels at day 45 demonstrated a decrease (P<0.05) in fasting remnant-like particle-cholesterol (RLP-C) of 36%, an increase of red blood cell omega-3 fatty acid (RBC n-3) index of 109%, and an increase in the EPA to arachidonic acid ratio of 100%. The final fasting blood levels on day 91 demonstrated a 162% increase in RBC-n-3, and a plasma EPA:AA ratio increase of 137% compared to baseline. The placebo group had no significant alterations in variables in comparison to baseline. This study is an important example of the retro-conversion of DHA to EPA and demonstrates that, although DHA is a downstream metabolite of EPA, it can convert back to EPA when necessary.

Kelley DS, Siegal D, Vemuri M, et al. Docosahexaenoic acid supplementation decreases remnant-like particle-cholesterol and increases the (n-3) index in hypertriglyceridemic men. J Nutr 2008;138:30-36.