Cod liver oil is a pale yellow oil obtained from the livers of cod fish (family Gadidae). Most cod liver oil is obtained from the North Atlantic cod, Gadus morhua, although a North Pacific species, Gadus macrocephalus, is also used. Chief producers of the oil include Norway, Iceland, and Japan. One of nature's richest sources of vitamin D and vitamin A, cod liver oil is also an excellent source of the omega-3 essential fatty acids EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid).
Most of the uses for cod liver oil relate to its vitamin and essential fatty acid content. Its vitamin D content makes cod liver oil useful for promoting mineral absorption and bone strength. The high levels of vitamin A in cod liver oil can promote vision, skin health, and immune function. Cod liver oil's high omega-3 essential fatty acid content may make it helpful for cardiovascular health as well.
A common dosage recommendation for cod liver oil is one teaspoon per day, which supplies 92% of the daily value for vitamin A and 115% of the daily value for vitamin D. Because high intakes of vitamins A and D can lead to toxic accumulations in the body, cod liver oil intake above two teaspoons per day is generally not recommended.