Cod Liver Oil vs. Fish Oil

Fish oil and cod liver oil are two popular supplements known for their high levels of omega-3 fatty acids, which are essential for heart health and brain function, among other benefits.

Both oils provide similar benefits, but they come from different sources and are taken in different doses. If you’re unsure about which oil to choose, this article offers helpful information.

What is Cod Liver Oil?

As the name implies, cod liver oil is derived from the liver of codfish, also referred to as “sablefish,” “Alaskan black cod,” or “butterfish.”

Cod liver oil is renowned for its rich content of omega-3 fatty acids (EPA and DHA), as well as vitamins A and D. It has been traditionally used to support heart health, reduce inflammation, and overall wellness due to its beneficial nutrient profile.

According to the USDA, a tablespoon of cod liver oil contains 13600 IU of vitamin A and 34 micrograms of vitamin D [*].

Related: Top 9 Fish High in Omega-3 Fatty Acids

What’s the Difference Between Cod Liver Oil and Fish Oil?

Below is a table summarizing the key differences between cod liver oil and fish oil to help you make an informed choice.

Cod Liver vs. Fish Oil Benefits

Cod liver oil's combination of omega-3 fatty acids and vitamins A and D can be especially beneficial in certain situations where comprehensive nutritional support is a priority.

For instance, people living in regions with limited sunlight exposure, especially during winter months, may struggle to get enough vitamin D from natural sources. Cod liver oil, with its high vitamin D content, can help support this need.

Unlike cod liver oil, fish oil is derived from the flesh of various fatty fish like salmon, mackerel, and sardines. It typically does not contain significant amounts of vitamins A and D — however, it generally offers a higher concentration of omega-3 fatty acids.

This focus on omega-3s alone makes fish oil a preferable choice for those seeking the specific health benefits of EPA and DHA without additional vitamin intake [*].

Related: Is Cod Healthy? Nutrition, Benefits, and Risks

Cod Liver vs. Fish Oil Risks

Cod liver oil, while beneficial, carries certain risks, particularly related to its high vitamin A and D content.

Vitamin A toxicity can occur if consumed in excessive amounts over time, leading to symptoms like dizziness, nausea, headaches, and even liver damage. This is because vitamin A is a fat-soluble vitamin, meaning the body stores it, and excess intake can accumulate to harmful levels.

Similarly, the high vitamin D content in cod liver oil can cause hypercalcemia (elevated calcium levels in the blood) if taken inappropriately.

On the other hand, fish oil, while generally safe and widely used, also has potential risks. Since fish oil is derived from the flesh of various fatty fish, contamination can be a concern if the oil is not properly purified.

Fish can accumulate harmful substances like mercury, dioxins, and PCBs (polychlorinated biphenyls) from their environment, and without proper processing, these toxins could be present in fish oil supplements.

Dosage

When it comes to dosage, cod liver oil and fish oil require different considerations due to their distinct nutritional profiles.

Cod liver oil is usually taken in lower doses due to its high content of vitamins A and D, which can accumulate and potentially lead to toxicity if consumed excessively. The common dosage is 1 to 2 teaspoons per day, although this can vary based on the supplement and individual health needs.

Fish oil generally allows for a broader range of dosages because it focuses primarily on omega-3 fatty acids without additional vitamins. According to The National Institutes of Health, individuals can consume 1.1-1.6 grams of omega-3 fatty acids a day [*]. However, for lowering blood pressure, 3 grams of omega-3 fatty acids per day may be optimal.

Forms Available

Cod liver oil is commonly found both liquid and softgel capsule forms. The liquid form is often preferred for those seeking to combine it with other ingredients or those who prefer a more traditional approach, while softgels offer convenience and a more palatable option for those who dislike the taste of the oil.

Fish oil is available in multiple forms. This includes liquid, softgel capsules, and enteric-coated tablets. The enteric-coated tablets, in particular, are designed to minimize fishy aftertaste and reduce gastrointestinal discomfort by preventing the oil from breaking down until it reaches the intestine.

Price

Cod liver oil tends to be more expensive due to its added value of vitamins A and D, as well as the traditional methods used in its production. The cost can vary widely based on the brand, purity, and concentration of the oil, but it is generally priced higher than standard fish oil.

Fish oil is often less expensive and comes in a wider range of price points, especially for basic formulations that provide omega-3 fatty acids without additional vitamins.

Is Cod Liver Oil and Fish Oil Safe?

Cod liver oil and fish oil are generally safe for most people when taken at recommended dosages. Choosing high-quality supplements and adhering to recommended doses can help mitigate risks such as vitamin A toxicity, hypercalcemia, and consuming harmful substances.

As always, consulting with a healthcare provider is advisable, especially if you have underlying health conditions or are on medication.

Can You Take Cod Liver Oil and Fish Oil Together?

Taking them together is generally not recommended because it may lead to excessive intake of omega-3 fatty acids and, in the case of cod liver oil, additional vitamins A and D. It’s usually better to choose one based on your specific health needs.

Summary

Both fish oil and cod liver oil can be valuable additions to your lifestyle. If you have specific goals that align with the benefits of one of these supplements, you might consider incorporating it into your routine.

Eating black cod (sablefish) can also provide some of the benefits associated with cod liver oil. For a high-quality, delicious source of sablefish, consider Alaskan Salmon Company’s Wild Caught Alaskan Sablefish fillets. These are sustainably harvested from the pristine waters of Alaska, which means you get the freshest and most nutritious fish available.