With so much of the global omega-3 market built upon the success of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), it can be easy to lump the two fatty acids together. But it’s important not to overlook key differences between the two, such as new study results suggesting fish oil–derived DHA may be more effective than EPA at modulating blood lipids and specific markers of inflammation.
Writing in The American Journal of Clinical Nutrition, researchers in Canada conducted a double-blind, randomized, crossover, placebo-controlled study on 154 healthy adults with abdominal obesity and low-grade systemic inflammation. For periods of 10 weeks, participants were randomized to consume either 2.7 g per day of fish oil EPA, fish oil DHA, or a corn oil placebo, each in 3-g tablets. The supplementation periods were separated by nine-week washout periods.
By assessing blood markers, researchers found that DHA was more effective than EPA at attenuating systemic inflammation, as evidenced by a greater reduction in interleukin-18 and a greater increase in adiponectin. There was not a significant difference found between DHA and EPA for other inflammation factors like interleukin-6, tumor necrosis factor-α, and C-reactive protein.
In terms of blood lipids, supplementation with DHA compared to EPA led to more pronounced reductions in triglycerides and the ratio of cholesterol to HDL-cholesterol. DHA was also found to be more effective than EPA at increasing HDL-cholesterol and LDL-cholesterol, with a significant increase to LDL-cholesterol observed for DHA compared to EPA among men (but not women).
“Data from this carefully controlled [randomized controlled trial] indicate that DHA supplementation at a dose of ~3 g per day for 10 weeks may be more potent in modulating inflammation markers than would be a similar dose of EPA in men and women with abdominal obesity and subclinical system inflammation but who are otherwise health,” researchers concluded.
The study authors also noted that to their knowledge, this is the first study to offer a head-to-head comparison of EPA and DHA with inflammation markers as a primary outcome in both men and women.
The study included 48 men (mean age 57 +/- 12) and 106 women (mean age 50 +/- 16). Douglas Laboratories (Pittsburgh, PA) provided the fish oil supplements used in this study.
Nutritional Outlook Magazine
Allaire J et al., “Randomized, crossover, head-to-head comparison of EPA and DHA supplementation to reduce inflammation markers in men and women: the comparing EPA to DHA study.” The American Journal of Clinical Nutrition. Published online June 8, 2016.