Treatment strategies for cardiovascular disease that reduce inflammation are an important area of research. The omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) both reduce inflammation by decreasing pro-inflammatory cytokines and increasing anti-inflammatory compounds, although EPA may be more cardioprotective. In a recent report, investigators tested the effects of EPA and DHA supplementation on vascular inflammation, a mediator of atherosclerosis.

In epidemiological research, higher fish consumption is associated with lower risk of cardiovascular disease and death. In clinical trials, EPA supplementation reduced major cardiovascular events in those with high cholesterol; however, the role of inflammation in this research is unclear.

In the first experiment, participants consumed 4 grams of either EPA only, DHA only, EPA + DHA (2:1 ratio), or a placebo for 30 days. They completed a health assessment and gave a sample of blood before and after treatment. The researchers used the serum collected from participants to culture human vascular cells and measured the response of those cells to an inflammatory stimulus. In a second experiment of acute inflammation, researchers treated mice with EPA (600 milligrams per kilogram of body weight), DHA (600 milligrams per kilogram body weight), olive oil, or no treatment daily for 30 days. They measured several markers of vascular inflammation and blood lipids before and after treatment. Finally, in a third experiment of chronic inflammation, the researchers fed mice a heart disease-promoting diet for 16 weeks. During the final eight weeks of the diet, they treated mice with the same EPA, DHA, olive oil, or no treatment conditions as the second experiment and measured markers of atherosclerosis and blood lipids.

In humans, EPA supplementation reduced markers of vascular inflammation better than DHA only or fish oil. In mice from the second experiment, both EPA and DHA supplementation significantly reduced multiple markers of vascular inflammation without affecting cholesterol and triglyceride levels. EPA was more effective in reducing inflammation than DHA. In mice from the third experiment, DHA and EPA both reduced cholesterol and triglyceride levels, with DHA being more effective. EPA supplementation reduced multiple markers of vascular inflammation; however, neither treatment improved markers of atherosclerosis.

The authors concluded the high-dose omega-3 supplementation can reduce vascular inflammation at early and late stages of cardiovascular disease. They also noted that the small sample size of their study may have limited their results and suggested that EPA supplementation should be tested in larger trials.

Link to full study.

Learn more about cholesterol and atherosclerosis in this episode featuring expert Dr. Ronald Krauss.