Flaxseed oil and fish oil are popular dietary supplements, both valued as sources of beneficial omega-3 fatty acids. Consumers often consider taking them together to maximize the intake of these fats, which support heart and brain health. The core question is whether combining these two supplements is safe and effective for optimizing overall omega-3 consumption. Understanding the differences in their chemical composition and how the body processes them is key to determining a proper supplementation strategy.
Distinguishing the Sources of Omega-3s
The omega-3 fatty acids in flaxseed oil and fish oil are chemically distinct, leading to different biological roles. Flaxseed oil provides alpha-linolenic acid (ALA), a short-chain omega-3 derived from plants that must be converted by the body for utilization. Fish oil, by contrast, is a source of long-chain omega-3s: eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). These marine-derived fats are already in the form the body can readily use for cellular functions.
The human body’s ability to convert ALA into the more active forms, EPA and DHA, is inefficient. Studies suggest that only about 5% to 15% of ALA converts to EPA, and less than 0.5% converts to DHA in adults. The remainder is often used for energy or storage. This low conversion rate is why many people seeking direct benefits, such as anti-inflammatory support, choose fish oil. Combining both supplements ensures intake of both plant-based ALA and readily available EPA/DHA.
Safety Considerations When Combining Supplements
Taking standard doses of flaxseed oil and fish oil concurrently is generally safe for most healthy adults. Both supplements contribute to overall omega-3 intake, and their mechanisms of action do not typically conflict. However, users should be aware of potential additive side effects, especially those related to digestion.
Both oils can cause gastrointestinal distress, including loose stools, diarrhea, or nausea, particularly when consumed in high doses or on an empty stomach. Combining high amounts of both supplements increases the likelihood and severity of these digestive issues. A more significant consideration involves the theoretical risk of excessive blood thinning due to the anti-platelet activity of omega-3s.
While both ALA and the long-chain omega-3s have mild blood-thinning properties, the risk of clinically significant bleeding is low at typical supplemental doses. Individuals taking prescription anticoagulant or antiplatelet medications (blood thinners) should consult a healthcare provider before combining the two oils. This guidance is necessary to monitor for potential interaction with medication that could delay blood clotting.
Practical Guidelines for Dosing and Timing
To minimize potential side effects and maximize absorption, take both flaxseed and fish oil with a meal containing other dietary fats. Consuming these oils with food helps emulsify the fats, which improves bioavailability and reduces the risk of gastrointestinal upset, including the “fishy burps” associated with fish oil. Splitting the doses throughout the day, such as taking one with breakfast and the other with dinner, can help maintain steady levels in the body.
Flaxseed oil is available as a liquid or in capsules, while fish oil is typically found as a liquid or softgel. Regardless of the form, proper storage is necessary to prevent the delicate polyunsaturated fats from oxidizing and turning rancid. Both oils should be stored in a cool, dark place, ideally the refrigerator, and protected from light, heat, and air.
The goal of combining the supplements is to achieve a balanced intake of various omega-3s without creating an imbalance with omega-6 fatty acids. The standard recommendation for total daily EPA and DHA from fish oil is often around 1,000 milligrams. Flaxseed oil provides an excellent source of ALA. Choosing a moderate dosage for each supplement ensures a broad spectrum of omega-3s while respecting digestive limits.