Omega-3 fatty acids have been shown to deliver health benefits for cardiovascular support, cognitive function and joint integrity. However, it is important to also recognize the potential risks associated with their use.  

One of the primary risks associated with supplementation revolves around the potential for excessive bleeding or interference with blood clotting mechanisms. Omega-3 fatty acids, particularly high doses of EPA and DHA, have been shown to exhibit antithrombotic properties, which may increase the risk of bleeding, especially when combined with certain medications or in individuals with bleeding disorders.1 

In a group of randomized trials of pharmacologic strength omega-3, higher plasma levels of n3-FA (EPA and EPA+DHA, but not DHA) were associated with significantly fewer hospitalized bleeding events, and higher DHA levels (not EPA or EPA+DHA) with fewer atrial fibrillation events.2 So, bleeding is a critical consideration for individuals scheduled for surgery or those taking anticoagulant medications.

Quantities of omega-3 supplements should also be considered, as greater than three grams may cause gastrointestinal disturbances such as nausea, diarrhea or indigestion, and in some cases, individuals may be more prone to oxidative stress due to the susceptibility of polyunsaturated fats to oxidation.3 

Concerns have also been raised about the potential for contaminants, such as mercury and other environmental toxins, in certain fish oil supplements. This issue emphasizing the importance of sourcing products from reputable manufacturers. Some suppliers now have a form of omega-3 that is 100% vegan, naturally derived from micro-algae (Schizochytrium sp.) which has particularly high contents of DHA and EPA.  

Omega-3 fatty acids have also shown promise in certain studies on mental health, however, the evidence of efficacy in treating all mental health conditions remains inconclusive. A recent meta-analysis shows promise of using more EPA omega-3 than DHA omega-3; thus supporting the finding that omega-3 PUFAs with EPA 60% at a dosage of ≤1 grams per head per day (g/d) could have beneficial effects on depression.4 It is important to approach the use of omega-3 supplements for mental health with an understanding of the current scientific evidence and to consider them as part of a comprehensive treatment plan under the guidance of health care professionals.

Always remember that you must measure to manage your health. Measuring omega-3 levels in your blood can be done with a simple fingerstick or whole blood test. Biogena, a supplement company, recently measured omega-3 levels, along with numerous other blood biomarkers in relationship to mental health. They found that if your omega-3 index was above 10%, your psychological well-being was better as a whole including stress protection, sleep quality and less depression.5

In summary, omega-3 fatty acids can offer potential benefits. When seeking optimal health, measure your outcomes by measuring omega-3 levels in the blood. The quality and purity of supplements should also be carefully evaluated to mitigate the risk of exposure to contaminants. Informed decision-making, in consultation with a health care provider, is crucial to ensuring the safe and effective use of omega-3 supplements for health.

Dr. Underwood is a doctor of public health, a certified nutritionist, exercise physiologist and preventive practitioner with Healthy Futures, Inc. He can be reached at (760) 238.1446 or at [email protected]. For more information, visit

References available upon request.

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