EPA & DHA: What’s the difference?
The recent spike in research on the many benefits of omega-3 fatty acids has caused their popularity to grow exponentially, even earning them the title of “superfood”. The merit of omega-3 remains uncontested - there are, however, two types of omega-3s: eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). This raises some questions - which kind of omega-3 is better? Do they do the same thing? In what ways are they different? Is it really necessary to include both of them in your diet? How much of each do you need?
The reality is that, while both omega-3 fatty acids share similarities (they can both reduce triglyceride levels, for example), they differ structurally, and therefore also differ in their respective effects on the body. Nevertheless, both EPA and DHA are needed to maintain health and wellbeing, and should both be included in your diet. To find out more about the differences between EPA and DHA and why they’re both important, read on below.
One of the most popular uses of omega-3 is for the purpose of reducing inflammation, and in this regard, EPA is the more effective omega-3.
EPA regulates inflammation in a number of ways. First, EPA binds to and inhibits the enzyme that produces arachidonic acid (AA), which is responsible for activating the eicosanoids that promote cellular inflammation - so the more EPA you ingest, the less AA is produced, and the less inflammation results. DHA, in contrast, has a shape that makes it structurally incompatible with the enzyme that produces AA. As a result, DHA is unable to inhibit AA production, making it less effective at reducing inflammation.
EPA also competes with AA to bind to the enzyme phospholipase A2, which is needed to liberate AA so that it can activate pro-inflammatory eicosanoids. More EPA means that less sites on the enzyme phospholipase A2 are available for AA to bind to, resulting in less AA being liberated throughout the body, and therefore less overall inflammation. Because EPA and AA are in competition for the enzymes that activate pro-inflammatory eicosanoids, EPA also has the power to reduce inflammation in the brain - despite the fact that there is actually very little EPA itself present in the brain.
Inflammation plays a role in the precipitation of many health issues and chronic diseases, and since EPA reduces inflammation, it can help to prevent many health complications before they wreak havoc on the body. For instance, evidence suggests that EPA exerts beneficial effects on artery plaque progression and blood clot formation through its anti-inflammatory effects, which hinders the development of atherosclerosis. In fact, an analysis of the Japan EPA Lipid Intervention Study found a 19% relative reduction in coronary artery disease with pure EPA and statin drugs as opposed to statins alone. It also found that high EPA levels were associated with less risk for major coronary events, such as heart attacks, heart failure, and angina.
The beneficial anti-inflammatory effects of EPA may also extend to other health issues in which inflammation is a implicated, such as rheumatoid arthritis, lupus, and psoriasis. In addition, though the exact mechanism of action is unclear, recent meta-analyses also suggest that EPA, but not DHA, can be effective in reducing symptoms of depression.
Though EPA is the star when it comes to reduction of inflammation, DHA is necessary for physiological function, and has its own exclusive host of benefits.
Most notably, DHA’s larger structure allows it to take up more space in the cell membrane than EPA. This is beneficial because it increases the overall fluidity of cell membranes, which is important for proper function of the vesicles that contain and release neurotransmitters (the chemicals responsible for the transfer of nerve impulses).
The structure of DHA also results in a perpetual sweeping motion, disrupting clusters of lipids in the cell membrane, which makes it more difficult for cancer cells to thrive. In addition, DHA’s structure increases the size of low density lipoproteins (LDLs, known as “bad” cholesterol), reducing their ability to seep into the lining of arteries and create atherosclerotic plaques.
Recent research also suggests that DHA has protective effects on the liver, as a study observing mice given foods coinciding with the typical Western diet (disproportionately high in fat and red meat) found that mice who were supplemented with DHA enjoyed beneficial changes in vitamin, carbohydrate, lipid, and protein metabolism - all of which contribute to optimal hepatic function.
The Bottom Line
Both types of omega-3 are necessary for the maintenance of physiological function, though they both differ in their structure and effects on the body. As the reduction of inflammation is omega-3’s most significant benefit with the broadest impact, a higher ratio of EPA to DHA is usually the more suitable option for those looking to improve their overall health.
So what’s the ideal ratio of EPA to DHA? In a perfect world, it would be 1-2:1 - however, considering the fact that the typical Western diet has Americans ingesting far more DHA than EPA (at a ratio of up to 20:1, to be specific), a supplemental ratio of approximately 5:1 EPA/DHA is the most beneficial in terms of correcting existing EPA/DHA imbalances, reducing inflammation, helping to prevent health complications (particularly cardiovascular issues), and maintaining overall health and wellbeing.