Cod liver oil has been popular since the ancient Romans and Vikings used it to maintain strength and promote good health. Fish oil, such as cod liver oil, is a good source of omega-3 fatty acids, which may boost your immune system, prevent heart disease and even improve your skin. One of the reasons for cod liver oil's heart benefits is the fact it can thin your blood, but this ability can also have adverse side effects for some people.
Cod Liver Oil Versus Fish Oil
Fish oil supplements are made from the whole fish parts of various cold-water species, including mackerel, anchovies and sardines. Cod liver oil, on the other hand, is exactly what is sounds like --- oil extracted from the livers of cod fish or sometimes halibut. Both fish oil and cod liver oil contain high concentrations of the omega-3 fatty acids eicosapentaenoic acid, or EPA, and docosahexaenoic acid, or DHA. However, cod liver oil has a higher ratio of DHA to EPA and much greater amounts of vitamins A and D.
Blood-Thinning Properties
Omega-3 fatty acids are essential nutrients that your body needs but can't make on its own. Omega-3 acids thin the blood by preventing platelets from sticking together to form clots within blood vessels, as well as reducing fibrin, another compound involved in blood clotting. The stickier the blood, the less likely it is for you to bleed easily and the more likely it is that you might form clots. Omega-3s also have the ability to reduce inflammation, which can improve elasticity of your blood vessels and reduce plaque buildup on artery walls that leads to clots and heart disease.
Expert Insight
Research published in the journal "Circulation" in 1983 supplemented the diets of healthy volunteers for eight days with cod liver oil. After the study period, the subjects had decreased levels of platelets and increased bleeding time, effects that wore off four weeks after the supplements were stopped. A 1984 study in the publication "Lipids" also showed that using cod liver oil significantly reduced thrombin-induced platelet aggregation and increased bleeding times by 81 percent.
Dosage
High doses of cod liver oil contain high levels of vitamin A, which can be toxic and cause a wide range of health problems from bone loss to gastrointestinal problems to birth defects. Because of these concerns and the fact that there is no recommended dosage of cod liver oil, check with your doctor before taking oil supplements. Nutrition expert and author Dr. Ray Sahelian recommends taking one cod liver oil softgel daily and notes studies where patients with rheumatoid arthritis ingested 1 g of cod liver oil daily for three months with few side effects. The 1983 "Circulation" study used 40 ml/day of cod liver oil.
Considerations
Due to the blood-thinning potential of cod liver oil, avoid taking it if you have a bleeding disorder such as hemophilia or if you are taking a blood-thinning medication such as Plavix, Coumadin or aspirin, as the cod liver oil could cause serious bleeding. If you are allergic to fish, you should also avoid cod liver oil. Less serious side effects can include diarrhea, gas and a fishy odor to your body and breath.
References
- "Circulation"; Platelet Function, Thromboxane Formation and Blood Pressure Control During Supplementation of the Western Diet with Cod Liver Oil; R Lorenz, et al.; 1983
- RaySahelian.com; Cod Liver Oil; Ray Sahelian, M.D.
- University of Maryland Medical Center; Cod Liver Oil; January 2010
- "Lipids"; Alteration and Recovery of Bleeding Times, Platelet Aggregation and Fatty Acid Composition of Individual Phospholipids in Platelets of Human Subjects Receiving a Supplement of Cod-liver Oil; A.A. Ahmed and B.J. Holub; 1984
- "Parade"; Do Fish-Oil Supplements Thin the Blood?; Isadore Rosenfeld, M.D.
Member Comments