Fish Oil is derived from various fish such as pilchards, sardines, mackerel and herring. It contains a much higher percentage of EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) than Cod Liver Oil but only low levels of vitamins A and D. EPA and DHA are omega-3 fatty acids, which are converted in the body to produce prostaglandins. These affect a wide variety of physiological processes due to their modulation effect on the action of hormones. It is thought that EPA and DHA may lower serum triglycerides (harmful blood fats), reduce the risk of blood clots and irregular heartbeat, have anti-inflammatory properties and support the immune system. DHA is essential for normal brain development in unborn babies and for normal brain function throughout life.