Oil derived from fatty fish is used to treat or prevent a wide range of health ailments, but choosing between all of the different fish oil options can be confusing. One of the main decisions when picking a supplement is whether to choose standard fish oil or cod liver oil, both of which are widely available. Understanding the differences between these two types of supplements can help you make the best choice for your health.
Sources
Cod oil comes from the liver of codfish. Fish oil can be made from a single fish or from a mixture of fish species. Common fish used to produce fish oil include mackerel, herring, tuna, halibut, salmon and cod. Many fish oil preparations are made from salmon oil. The oil from these fish may be taken from any fatty area of the fish's body, not just the liver.
Omega-3 Fats
Omega-3 fats are the major beneficial component in oils derived from fatty fish. Omega-3 fats taken in the form of fish oil may lower triglycerides, reduce the risk of heart disease and lower blood pressure, according to MayoClinic.com. Fish oil contains two types of omega-3 fats, DHA and EPA. DHA has been linked to providing protection against neurodegenerative disease and promoting healthy brain development. EPA may be useful for promoting joint health and treating autoimmune disorders such as arthritis. Both cod liver oil and fish oil contain high levels of EPA and DHA, although the exact amount may depend on the specific fish used to provide the oil.
Vitamins
Cod liver oil is naturally high in vitamin A and vitamin D, both of which are found in animal livers. Fish oil not derived from the liver doesn't contain much of these two nutrients unless they are added during processing. A 2005 letter in the "Journal of the American Board of Family Medicine" recommends using cod liver oil instead of fish oil for individuals with low levels of vitamin D, since this nutrient is present at much higher levels in cod liver oil than in fish oil. Fish oil manufacturers often add vitamin E as a preservative. Some brands or formulations also include other nutrients, such as calcium, iron and vitamins B1, B2, B3 and C.
Potential Problems
Some fish are contaminated with mercury, a heavy metal compound that can build up in the body and cause brain damage if consumed in large enough amounts over time. Most fish oil manufacturers purify and test their oil for mercury, and mercury accumulates at much lower levels in fish oil than in fish meat. For these reasons, commercially available products in the U.S. are typically considered safe. The high levels of vitamin A in cod liver oil may also be problematic. According to UC Berkeley Wellness Guide to Dietary Supplements, cod liver oil has up to 4,500 IU of vitamin A per tbsp. Doses of 6,000 IU may inhibit growth and can lead to fractures. Pregnant women or women planning on becoming pregnant should not take doses higher than 10,000 IU, since consumption at this level is linked to birth defects.
Member Comments