What is Cod Liver Oil?

Tricia Christensen
Tricia Christensen

Cod liver oil is a specific type of fish oil, made from steam cooking cod livers. The livers are then pressed, and the oil is gathered. Cod liver oil may come in liquid or capsule form, and is high in both vitamins A and D. It is also an excellent source for omega-3 fatty acids.

Cod liver oil tablets.
Cod liver oil tablets.

Traditionally, cod liver oil was a patent remedy for a number of childhood ailments. Children unfortunately had to take it in liquid forms that, depending upon their quality, could be vastly unpleasant in taste. Some oil tastes quite rancid and extremely fishy; numerous baby boomers still shudder at the thought of having to take a dose of it.

Mint is often used to cut the flavor of cod liver oil.
Mint is often used to cut the flavor of cod liver oil.

Though many older remedies have proven unhealthful, cod liver oil actually did deliver a high dose of vitamins, and may have promoted heart health. It was not a cure-all, though it was frequently used to treat a variety of ailments. Most often children took a daily dose as part of a healthy diet.

Though cod liver oil has its merits, it may be too high in vitamin A. In higher doses, it definitely exceeds the recommended daily allowance (RDA) for this vitamin. It has been shown that vitamin A from liver sources may in fact be harmful when taken during pregnancy, and most prenatal vitamins have relatively low levels to prevent increasing the risk for developing diabetes during pregnancy.

Male adults and women who are not pregnant may actually benefit from cod liver oil more than fish oil, particularly during winter months. This is because its vitamin D levels have been shown to compensate for a lack of exposure to sunlight during winter. Many experts recommend switching to fish oil during spring and summer since people generally get adequate levels of vitamin D from sunlight during these times. Further, if a person drinks milk fortified with vitamins A and D, it may be better to stick to regular fish oil.

Since cod liver oil now comes in capsule form, many are spared having to taste it, though a person may have an unpleasant burp or two that will taste intensely fishy. There is also flavored oil in liquid form. Some use mint or orange flavors to cut down on the bad taste.

People affected with different forms of arthritis often take a daily supplement of cod liver oil as it is thought to reduce joint pain. Like fish oil, it may also be heart healthy. One caution exists for those who regularly experience heart arrhythmias. Fish oil has been shown in recent studies to increase risk of arrhythmias in those who have already experienced heart rhythm problems. Though cod liver oil has not been studied for the same possible effect, it may be wise to consult a medical professional prior to taking it.

Consumers should be sure to buy cod liver oil supplements that are free from mercury and other toxins.
Consumers should be sure to buy cod liver oil supplements that are free from mercury and other toxins.
Tricia Christensen
Tricia Christensen

Tricia has a Literature degree from Sonoma State University and has been a frequent wiseGEEK contributor for many years. She is especially passionate about reading and writing, although her other interests include medicine, art, film, history, politics, ethics, and religion. Tricia lives in Northern California and is currently working on her first novel.

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Discussion Comments


What is the difference between cod liver oil and fish oil?

Is there one that is better to take than the other, or are there any especial pros and cons?

I'm trying to decide on what source of omega-3 and vitamin D, and have got it down to these two -- any advice or personal experiences to share?


Ooh, I remember having to take that pure cod liver oil as a child and hating it!

I've never really liked fish since, so I mostly stick to flax seed for my omega-3s now.


One thing to watch out for when buying cod liver oil supplements is the source of the cod.

Unfortunately, some cod liver oil supplements also have a high lead and mercury content.

Most higher-quality cod liver oil supplements are purified to get rid of most pollutants, but it is still good to double-check the purity of your supplements before you buy.


how many cods livers are needed to make one capsule. this question is driving me mad. any replies are most welcome.

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