What are the differences between cod liver oil and fish oil?

Both cod liver oil and fish oil are oils derived from fish. It is an excellent source of omega-3 fatty acids, which can reduce the risk of having some chronic illnesses or diseases.

Although cod liver oil is a type of fish oil, what is commonly referred to as “fish oil” comes from a variety of sources.

There are many differences between cod liver oil and fish oil. For example, they contain varying levels of omega-3 fatty acids and several vitamins.

In this article, we explain the differences between cod liver oil and fish oil. We also list some benefits and risks of each oil.

Differences

Both cod liver oil and fish oil are good sources of omega-3s. Omega-3s are a group of fatty acids that, in small doses, are important for human health.

Several studies have focused on three types of omega-3s: alpha-linolenic acid (ALA), docosahexaenoic acid (DHA), and eicosapentaenoic acid (EPA). The benefits of each vary slightly, so taking all three can improve health.

One has to get these acids from their diet; the body does not create all the acids. ALA is converted to EPA and then DHA, but the conversion rate is low. To attain optimal levels of Omega-3 levels, one must take DHA and as well as EPA.

Cod liver oil is a type of fish oil. The main differences between cod liver oil and other fish oils include:

Differing vitamins: Cod liver oil contains vitamins A and D.
Omega-3 content: Cod liver oil comes from the liver of the codfish, which is less fatty than other fish, like tuna and mackerel. For that reason, cod liver oil offers a lower dose of omega-3s.
Other health benefits: In addition to the purported benefits of omega-3s, cod liver oil has long been a popular folk remedy for managing constipation and inducing labour.

Benefits of cod liver oil and fish oil

Although cod liver oil is a type of fish oil, people commonly use the term “fish oil” to refer to more fatty fish oils, such as tuna and mackerel oil.

Several studies have shown that omega-3s can improve heart health by lowering blood pressure or reducing the risk of a heart attack. Most of this research focuses on populations with a lot of fish oil in their diets, not on people who supplement with fish oil.

Not all studies support this potential benefit. A reliable source of diabetics in 2012 found that omega-3 supplements lowered triglyceride levels but did not reduce the risk of a heart attack.

Omega-3 supplements, including fish oil, may also:

help manage symptoms of rheumatoid arthritis
lower the risk of dry eye and age-related macular degeneration

Researchers continue to study omega-3s for a variety of conditions, but the data so far is not conclusive. For example, a 2019 meta-analysis of omega-3s showed it could improve symptoms of depression, but other research is inconclusive or undermined the claim.

Like other fish oils, cod liver oil can reduce the risk of medical conditions. A study from 2014 followed a group of people who took cod liver oil and a group who did not, found a lower risk for heart health conditions in the group who took cod liver oil.

The study also found that cod liver oil consumers had more health problems and were more likely to report bone disease and benign growths.

The study authors suggested that people with health problems were more likely to consume cod liver oil. They also found that cod liver oil consumers had healthier lifestyles, suggesting that other differences could explain the differences in health outcomes between the groups.

Some other research source also hints at the health benefits of cod liver oil. A 2011 study emphasizes that, because it is a source of both omega-3s and vitamin A, cod liver oil may help protect against glaucoma.

Emerging evidence suggests, but does not conclude, that the risk of severe COVID-19 illness is higher in people who do not get enough vitamin D.

Risks of cod liver oil and fish oil

Because cod liver oil and fish oil are both fish oils that contain omega-3 fatty acids, the risks are similar. They include:

Fish allergies: Fish oil supplements may trigger some fish allergies. In some people, the reaction may be severe.
Stomach issues: Some people who take fish oil supplements experience stomach issues such as bloating, gas, diarrhoea, or constipation.
Bad taste: Fish oil can leave a fishy taste in the mouth, and a person might notice bad breath right after taking the supplement.
Blood pressure: Limited research suggests that omega-3s might lower blood pressure. People taking blood pressure medication should talk to a doctor before trying these supplements.
Blood clotting: Omega-3s might also affect blood clotting, so people with clotting disorders, bleeding disorders, and those taking clotting medication should talk to a doctor before supplementing with fish oil.
Interactions with other drugs: Doctors have not identified all possible drug interactions associated with fish oil, so people who take any medication that is vital for their health should talk to a doctor before supplementing.

Types of cod liver oil and fish oil

There are three main types of cod liver oil and fish oil supplements:

Food

A person can get cod liver oil by eating cod liver. Many foods, including most fish, are good sources of omega-3 fatty acids and may offer superior benefits to supplements. Fatty fish such as tuna and mackerel are highest in omega-3s.

Oils

Several manufacturers make pure fish oil formulas or fish oil that contains other supplements. These oils usually contain higher concentrations of fish oil, but may taste bad.