Cod-liver oil not only contains loads of omega-3 fatty acids, but vitamins A, D and E as well. Vitamin E does not naturally occur in cod-liver oil, but is added by the manufacturer. Omega-3 fatty acids have become popular dietary supplements in the prevention of heart disease. Also, omega-3 is touted as beneficial to those with arthritis, depression and poor bone health. Cod-liver oil is a good source of omega-3.
History
Cod-liver oil became a popular preventative for rickets, a bone deformity caused by vitamin D deficiency, around 1900. Scientists of the time estimated that 90 percent of children in industrialized England had rickets. Although medicinal use of cod-liver oil dates back to 1789, work by Edward Mellanby, John Howland and Elmer McCollum in studies of nutritional inadequacies, led to the use of cod-liver oil for the treatment of rickets. Current omega-3 research may lead to an additional use for cod-liver oil as a treatment for additional diseases and conditions.
Manufacturing Cod-Liver Oil
The oil is truly extracted from the liver of a fish called a cod. These large cold-water fish can be found throughout the Atlantic and Pacific oceans, sometimes growing up to 200 lbs. In the United States cod-liver oil is extracted using a wet steam process. The fish liver is cooked, pressed and separated. The collected oil is refined, deodorized and bleached for packaging. The environmental defense fund surveys cod-liver oil manufacturers for allowable limits of pollutants and the amounts of omega-3 fatty acids vary depending on the manufacturer.
Omega-3 Fatty Acids
The omega-3 fatty acids found in cod-liver oil include docosahexaenoic acid, DHA, and dicosapentaenoic acid, EPA. The World Health Organization recommends your adult combined intake at 0.3 to 0.5 g of DHA plus EPA. The U.S. Food and Drug Administration recommend that you should not consume more than 2 g of omega-3 fatty acids per day in the form of a supplement. You should calculate your daily dosage on the DHA and EPA content, not the total amount of fish oil. For example, Norwegian cod-liver oil contains only 20 percent of its total contents as DHA and EPA.
Possible Benefits
Cod-liver oil has been studied for many years for its medicinal properties. Recently, Lars Stene and colleagues in the 2000 issue of "Diabetologia" and the 2003 issue of the "American Journal of Clinical Nutrition" found a lower risk of type 1 diabetes in children of women taking cod-liver oil during pregnancy and in children who take a cod-liver oil supplement during their first year of life. Along with a significant decrease in deaths from cardiovascular disease and an improved anti-inflammatory association in cases of rheumatoid arthritis, these omega-3 benefits can be found in cod-liver oil.
References
- Mayo Clinic; Omega-3 Fatty Acids, Fish Oil, Alpha-Linolenic Acid; April 2011
- Vitamin & Herb University; Cod Liver Oil; 2009
- "Canadian Medical Association Journal;" Cod-Liver Oil, Vitamin D and the Fight Against Rickets; Peter Wilton; May 1995
- "Pediatrics;" Vitamin D, Cod-Liver Oil, Sunlight, and Rickets: A Historical Perspective; Kumaravel Rajakumar; 2003
- U.S. Environmental Protection Agency; Fish Processing; January 1995
- Environmental Defense Fund; How Safe Are Fish Oil Supplements; February 2011
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