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What is the Difference Between Cod Liver Oil and Fish Oil?

Angie Bates
Angie Bates

Fish oil is found in species of oily fish, such as tuna, halibut, and salmon. It can be obtained by eating fish flesh or through processed supplements, either in liquid or pill form. Cod liver oil is a type of fish oil made from the liver of a fish called cod. It is generally only found in nutritional supplements since people do not often eat fish livers. Cod liver oil and fish oil are used as dietary supplements often because they contain Omega-3 fatty acids.

Omega-3 fatty acids help decrease swelling and pain, acting as anti-inflammatory agents. The body cannot produce these fatty acids on its own, so it must rely on outside sources, such as fish oil, to obtain them. Since cod liver oil and fish oil contain Omega-3 fatty acids, they are often suggested to help arthritis suffers. Cod liver oil, in particular, is frequently suggested for this purpose, but all fish oil seems to work. Fish oil is also thought to help prevent heart disease and stroke because it aids in thinning the blood, preventing clotting.

Mackerel is often used as the source for fish oil tablets.
Mackerel is often used as the source for fish oil tablets.

Cod liver oil is made only from the livers of cod. A type of bottom-dwelling fish, cod live in the cold water of the Atlantic and parts of the Pacific oceans. Unlike most fish used for fish oil, cod is considered a white fish, not a oily fish. This is why the oil is supplied from its liver rather than its flesh.

Another difference between cod liver oil and fish oil is the amount of vitamin A present in the supplements. Fish oil in general contains very little vitamin A because that vitamin is not found in the fish flesh. Vitamin A is found in the liver, however, so cod liver oil contains high amounts of vitamin A, particularly when taken in the liquid form. Although vitamin A is helpful and necessary in small doses, in large doses it can cause bones to weaken and birth defects. There is also a concern when taking cod liver oil of contaminants since the oil is made from an organ which filters toxins.

Fish oil can come from salmon.
Fish oil can come from salmon.

As with any supplement, both cod liver oil and fish oil should be taken in moderation. High doses can increase the risk of bleeding and may impede the proper control of blood sugar in diabetic patients. Fish oil also may interact with high blood pressure medication by further decreasing blood pressure, causing it to drop to dangerously low levels. Conversely, some birth control and weight loss pills may decrease the effectiveness of fish oil.

Discussion Comments

burcinc

@ysmina-- There is a type of cod liver oil called "fermented cod liver oil" and it's supposed to be the best type out there. I've heard that it's safer and more beneficial.

I think that fish oil supplements or cod liver oil supplements can be taken for Omega 3 but they're not all created equal. I have used both supplements in the past but I made sure that the supplement was purified and up to standards.

So as long as you get a high quality supplement, you don't need to worry. But ask your doctor about it to make sure that it's safe for you.

discographer

@ysmina-- I don't think that cod liver oil is better than regular fish oil capsules in any way. Cod liver oil has the same benefits as fish oil, but it also usually contains synthetic vitamins, especially vitamin A. There is also the risk of it containing heavy metals and toxins, but the main issue with cod liver oil is vitamin A. Taking too much of it can cause vitamin A toxicity.

Especially pregnant women need to avoid cod liver oil because the excessive vitamin A is harmful for the baby.

ysmina

So in terms of toxins and heavy metals, fish oil is safer than cod liver oil? Does pure cod liver oil really have more EPA and DHA than fish oil?

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    • Mackerel is often used as the source for fish oil tablets.
      Mackerel is often used as the source for fish oil tablets.
    • Fish oil can come from salmon.
      By: dulsita
      Fish oil can come from salmon.
    • Some birth control pills reduce the effectiveness of fish oil.
      By: Kimberly Reinick
      Some birth control pills reduce the effectiveness of fish oil.
    • Soft gel capsules made with either fish or cod liver oil are an excellent source of omega-3 fatty acids.
      By: maron
      Soft gel capsules made with either fish or cod liver oil are an excellent source of omega-3 fatty acids.
    • Research suggests that children with hyperactivity and some forms of autism can benefit from taking fish oil on a daily basis.
      By: Evgeniy Drogozhilov
      Research suggests that children with hyperactivity and some forms of autism can benefit from taking fish oil on a daily basis.
    • Fish oil supplements are rich in healthy fats, such as omega-3 fatty acids, eicosapentaenoic acid and docosahexaenoic acid, commonly called DHA.
      By: Stephen VanHorn
      Fish oil supplements are rich in healthy fats, such as omega-3 fatty acids, eicosapentaenoic acid and docosahexaenoic acid, commonly called DHA.