Study raises more concerns about the use of combined EPA/DHA through supplements Doctors often recommend Omega-3s to help patients lower their cholesterol and improve heart health. Those Omega-3s can come from fatty fish like salmon and mackerel, or supplements that often contain a combination of the acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Now, a new study from the Intermountain Healthcare Heart Institute in Salt Lake City finds that higher EPA blood levels alone lowered the risk of major cardiac events and death in patients, while DHA blunted the cardiovascular benefits of EPA. Higher DHA levels at any level of EPA worsened health outcomes.