It is becoming increasingly clear that EPA and DHA have different effects
Among the risk factors for cardiovascular disease (CD) are high cholesterol, high concentrations of low-density lipoproteins (LDL-c) and triglycerides (TG), low concentrations of high-density lipoproteins (HDL-c), small LDL particle size, high blood pressure, increased platelet activity, high levels of inflammatory markers, insulin resistance and high oxidative stress.
There seems to be an inverse dose-response relationship between fish oil consumption and the risk of mortality from CD. The omega-3 polyunsaturated fatty acids (n-3 PUFAs) eicosapentaenoic acid (EPA) docosahexaenoic acid (DHA), components of fish oil, are considered the cause of this beneficial effect. Most clinical studies have been carried out with concomitant administration of EPA and DHA; however, there is a growing interest in establishing the differential effects on cardiometabolic risk factors.
A systematic review of published articles on the subject up to May 2017, which selected six controlled randomised trials with doses of EPA or DHA > 2 g/day and purity ≥ 90% (with a total of 527 participants), reached the following conclusions: both EPA and DHA reduced the concentration of TGs, but the effect of DHA was greater; neither EPA nor DHA changed total cholesterol levels, but DHA increased the concentration of HDL-c and LDL-c and the size of the LDL particles; both FAs inhibited platelet activity, but DHA improved vascular function and reduced heart rate and blood pressure to a greater extent that EPA; and both reduced oxidative stress.
It is becoming increasingly clear that EPA and DHA have different effects.