Cod liver oil

Cod liver oilis adietary supplementderived fromliverofcod fish(Gadidae).As with mostfish oils, it contains theomega-3fatty acidseicosapentaenoic acid(EPA) anddocosahexaenoic acid(DHA), and alsovitamin Aandvitamin D.
Historically, it was given to children in the United States in the 19th Century's as a patent medicine and by the end of the century was being praised by doctors in medical journals.After it wasshown, in 1920 thatvitamin D deficiencywas the cause ofrickets, cod liver oil was given as a rich source of vitamin D.
Cod liver oil has traditionally come in many grades. Cod liver oil for human consumption is pale and straw-colored, with a mild flavor. ScandinavianVikingsproduced cod liver oil by laying birch tree branches over a kettle of water, and fresh livers were laid over the branches. The water was brought to a boil and as the steam rose, the oil from the liver dripped into the water and was skimmed off. There was also a method for producing fresh raw cod liver oil.
In theIndustrial Revolution, cod liver oil became popular for industrial purposes. Livers placed in barrels to rot, with the oil skimmed off over the season, was the main method for producing this oil. The resulting oil was brown and foul-tasting. In the 1800s cod liver oil became popular as a medicine and both pale and brown oils were used. Brown oils were common because they were cheaper to produce. Some doctors believed in only using the fresh pale oil, while others believed the brown oil was better. Therancidbrown oils tended to cause intestinal upset.
The Möller Process was invented by Peter Möller in 1850. The livers are ground with water into a slurry, then this is gently simmered until the oil rises to the top. The oil is skimmed off and purified.Other methods used in modern times include the Cold Flotation Process, pressure extraction, and pressure cooking. These all require further purification steps to get a pure oil.
Though similar in fatty acid composition to otherfish oils, cod liver oil has higher concentrations of vitamins A and D. According to theUnited States Department of Agriculture, atablespoon(13.6 grams or 14.8 mL) of cod liver oil contains 4,080μgofretinol(vitamin A) and 34 μg (1360 IU) of vitamin D.TheDietary Reference Intakeof vitamin A is 900 μg per day for adult men and 700 μg per day for women, while that for vitamin D is 15 μg per day. TheTolerable upper intake levels(ULs) are 3000 μg/day and 100 μg/day, respectively. People consuming cod liver oil as a source of omega-3 fatty acids should pay attention to how much vitamin A and vitamin D this adds to their diet.
Cod liver oil is approximately 20%omega-3 fatty acids. For this reason, cod liver oil may be beneficial insecondary prophylaxisafter aheart attack.Diets supplemented with cod liver oil have been demonstrated to have beneficial effects onpsoriasis,and daily supplementation has been shown to be correlated with lower rates of high-severitydepression.
A tablespoon (13.6 g) of cod liver oil contains 136% of the UL for preformed vitamin A (retinol).Vitamin A accumulates in the liver, and can reach harmful levels sufficient to causehypervitaminosis A.Pregnant women may want to consider consulting a doctor when taking cod liver oil because of the high amount of retinol.
Fatty acid oxidation and environmental toxins content are reduced when purification processes are applied to produce refined fish oil products.
InNewfoundland, cod liver oil was sometimes used as the liquid base for traditionalred ochrepaint, the coating of choice for use on outbuildings and work buildings associated with the cod fishery.
InTübingen, Germany, drinking a glass of cod liver oil is the punishment for the loser at the traditionalStocherkahnrennen, apunting boatrace byUniversity of Tübingengroups.