Omega-3 fatty acids are beneficial substances that you need to include in your diet to keep your body running properly. Cod liver oil contains significant amounts of omega-3s; however, these fatty acids are only constituent parts of cod liver oil, and other types of fish oil also contain them. You can also get omega-3s from sources other than fish oil.
Cod Liver and Omega-3s
In addition to cod liver, fish oil comes from the bodies of fish species that include tuna, herring, salmon, halibut and mackerel, as well as from whale blubber. The various sources of fish oil contain two main types of omega-3 fatty acids: docosahexaenoic acid, or DHA, and eicosapentaenoic acid, abbreviated as EPA. Inside the body, DHA and EPA help the brain maintain its everyday activities, in addition to supporting normal growth and development in infants. DHA- and EPA-containing fish oil supplements have potential medical uses that include heart disease prevention, blood pressure reduction and reduction of a blood-borne fat called triglyceride.
Non-Fish Sources
Another form of omega-3 fatty acid, called alpha-linolenic acid or ALA, comes from non-fish sources that include walnuts, walnut oil, flaxseeds, flaxseed oil, canola oil, pumpkins, pumpkin seed oil, tofu, soybeans and soybean oil. Certain ALA-containing products, like canola oil, are primarily meant for cooking; other ALA-containing products, like flaxseed oil, primarily play a medicinal or therapeutic role, according to the University of Maryland Medical Center. When you eat foods that contain ALA, your body takes some of this fatty acid and turns it into EPA and DHA.
Fish Oil in Food
In addition to taking fish oil supplements, you can get fish oil and omega-3 fatty acids by eating fish directly. However, while supplements frequently contain cod liver oil, cod as a whole is not an especially rich food-based source of omega-3s, MedlinePlus reports. Instead, the richest fish sources for these fatty acids include tuna, sardines, anchovies, trout, herring, mullet, sturgeon, menhaden, bluefish and mackerel. Fish oil capsules commonly contain about 120 mg of DHA and 180 mg of EPA. Fish oil-bearing species have varying amounts of these omega-3s.
Considerations
In addition to omega-3 fatty acids, cod liver oil frequently contains large amounts of vitamin A. While ALA may have some of the same heart health benefits as the other forms of omega-3, the support for these benefits is not as clear as the evidence supporting the use of EPA and DHA, MayoClinic.com notes. Food manufacturers can reduce some of the potential benefits of ALA by exposing omega-3-containing products to heat, light or air. Whatever the source of omega-3 you choose, you can help preserve its health benefits by keeping it refrigerated. Ask your doctor for more information on cod liver oil and all other omega-3 sources.
References
- University of Maryland Medical Center: Omega-3 Fatty Acids
- MedlinePlus: Fish Oil
- MayoClinic.com: Omega-3 Fatty Acids, Fish Oil, Alpha-Linolenic Acid (Pages 1 and 3)
- University of Maryland Medical Center: Alpha-Linolenic Acid
- Harvard School of Public Health: Ask the Expert; Omega-3 Fatty Acids; Dr. Frank Sacks
- University of California Berkeley Wellness Letter: Cod Liver Oil
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