Omega-3 fatty acids are a class of essential nutrients that are lacking in the modern diet. The two leading sources of omega-3 fatty acids are fish oil and flaxseed oil. Flaxseed oil is rich in the omega-3 fatty acid ALA where fish oil is rich in two other omega-3 fatty acids, EPA and DHA. EPA and DHA can be synthesized from ALA, but may not be synthesized to adequate levels.
Omega-3 Fatty Acids
Omega-3 fatty acids are essential raw materials in the production of signaling molecules, especially pro- and anti-inflammatory eicosanoids. Under-consumption of omega-3 fatty acids and over-consumption of omega-6 fatty acids, very common in the modern diet, may lead to chronic, low-grade inflammation.
Omega-3 fatty acids are also used to synthesize essential components of cellular membranes, especially in the brain, blood vessels and heart. Lack of omega-3 fatty acids in these membranes disrupts the normal signaling of these tissues raising the risk of heart disease and neuropsychiatric disorders such as depression, anxiety and bipolar disorder.
Fish Oil vs. Flaxseed Oil
ALA, alpha-linoleic acid, can be used to synthesize any omega-3 fatty acid needed by the body. EPA, eicosapentaenoic acid, and DHA, docosahexaenoic acid, are more easily used by the body and can be synthesized by ALA, albeit inefficiently.
Consumption of only flaxseed oil that contains mainly ALA is not always adequate to supply all the DHA and EPA the body requires. Fish oil is rich in both EPA and DHA. Healthy young women can typically convert 30% of ALA to EPA and DHA whereas men may only convert 12% of ALA to DHA and EPA. It appears beneficial, especially for men, to consume omega-3s from fish oil for the content of DHA and EPA.
Benefits
Supplementation of omega-3 fatty acids has not been consistently shown to be effective in treating disease. However, decreases in the blood levels of omega-3s has been associated with increased risk for many diseases including arthritis, heart disease, type 2 diabetes, cancer, skin disorders, osteoporosis and mood disturbances. Eat a diet neither deficient nor overly abundant in omega-3 or omega-6 fatty acids to promote optimum health.
Supplementation
Flaxseed oil and fish oil are normally consumed via gelcap supplements. A 15 ml, or 1 tbsp, portion of flaxseed oil contains 7 g of ALA. Fish oil concentration may vary, and the label on the supplement will usually supply the amount of DHA and EPA. For those using flaxseed oil as a substitute for fish oil, 7.2 g of flaxseed oil is approximately equivalent to 1 g of fish oil in terms of production of EPA and DHA.
Omega-3 supplements may change the dosage needed for certain medications or may interfere with the absorption of medications taken at the same time. Always check with your doctor before beginning supplementation.
References
- University of Maryland Medical Center: Medical Reference: Complementary Medicine: Omega-3 Fatty Acids
- University of Maryland Medical Center: Medical Reference: Complementary Medicine: Flaxseed Oil
- Oregon State University: Linus Pauling Institute: Micronutrient Information Center: Essential Fatty Acids
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