Q: My neighbor swears by cod liver oil and says I should try it. Could it improve my health?
Drinking cod liver oil may help you if you happen to be deficient in either vitamin A or vitamin D. A type of fish oil, cod liver oil is a good source of the fat-soluble vitamins A and D. It also may contain Omega-3 essential fatty acids like other types of fish oil, helping ease achy joints and minor muscle aches.
Although it’s has been around a long time, cod liver oil didn’t start out as a medicine. It was originally a byproduct of the Norwegian fishing industry and commonly used to soften leather and as a hoof dressing for horses. Then in the 1800s German physicians discovered that cod liver oil cured children of rickets, a common disease at that time that caused serious bone deformities. It was also used successfully to treat joint aches, gout and “obstinate constipation”.
According to the United States Pharmacopeia (USP), Cod Liver Oil, USP is “a thin, oily liquid with a characteristic, slightly fishy odor and a definitely fishy taste” made by “steaming the livers of the Atlantic cod, then straining the oil that rises to the top of the vat or kettle”. Cod Liver Oil, USP lists 3 main ingredients: vitamin A, vitamin D and Omega-3 essential fatty acids.
By 1851, cod liver oil was declared “one of the most esteemed remedies currently available”. Doctors recommended it but children hated it and suggestions on how to improve the “fishy” taste of cod liver oil began to show up in medical and pharmacy references. The 19th edition of The United States Dispensary published in 1907 contains this advice for Cod Liver Oil, USP: “It may be taken alone or mixed with some vehicle calculated to conceal its taste and obviate nausea. Peppermint oil has been found to be helpful.” My favorite suggestion, taken from the same source, is to “chew a small piece of orange peel before and after taking the medicine.”
Cod liver oil may improve your health if your diet is low in either vitamin D or vitamin A. Vitamin D is essential to incorporate minerals such as calcium into new bone tissue. A nutritional deficiency of vitamin D causes rickets in children and osteomalacia in adults. In rickets, newly formed bone lacks minerals and is too soft, causing crooked bones and skeletal deformities. In adults, vitamin D deficiency causes weak bones, or osteomalacia. Deficiency of vitamin A can cause growth retardation, night blindness and an increased susceptibility to infections.
Each teaspoonful (5ml) of the official product of cod liver oil as Cod Liver Oil, USP contains 850 USP units of Vitamin A, 85 USP units of Vitamin D, and approximately 1 gram of Omega-3 essential fatty acids at a concentration similar to salmon oil.
The dose of cod liver oil recommended for children is one teaspoonful 3-4 times daily, and one tablespoonful (3 teaspoonfuls, or 15ml) 3-4 times a day for adults. Other formulations of cod liver oil besides the standard version contain extra vitamin A or D that’s been added by the manufacturer. The amount of Omega-3 fatty acids in cod liver oil varies, with formulas using Atlantic cod having the most and those from Pacific cod having little to none. It’s interesting that cod liver oil was considered helpful in chronic rheumatism (joint or muscle aches) because at least one product contained nearly the same concentration of Omega-3 fatty acids as today’s salmon oil supplements.
To reduce the prevalence of rickets in its children the United States began fortifying milk in the 1930’s with added vitamin A and D. Every 8 ounce serving of cow’s milk has 100 international units of Vitamin D which is 25% of its recommended daily intake and 150 units of vitamin A, which is 10% of its recommended daily intake. Today’s ready to eat cereals are also fortified with 10% of the recommended daily intake of both vitamins A and D. Rickets is now very rare in the United States.
Cod liver oil was one of the first effective vitamin supplements available, but thankfully there are more palatable options today to prevent deficiency of vitamin A and D. One tablet of either Centrum Silver® or Flintstones® chewable is today’s modern, and tastier, equivalent.
