Fish Oil vs. Cod Liver Oil: Which Is Better for Heart Health?

Fish oil and cod liver oil are both popular supplements touted for their heart health benefits, but they differ in key ways. According to the American Heart Association (AHA), both contain omega-3 fatty acids, but cod liver oil also provides vitamins A and D, which may affect their suitability for different individuals.

What Are the Key Differences?

Both supplements derive from fish, but their sources and nutrient profiles vary. Fish oil is typically extracted from fatty fish like salmon, mackerel, or sardines, while cod liver oil comes specifically from the liver of cod. A 2021 review in *Nutrients* found that fish oil is higher in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), the omega-3s most linked to cardiovascular benefits. Cod liver oil, however, contains higher levels of vitamin A and D, with one teaspoon providing up to 1,500 IU of vitamin A and 400 IU of vitamin D, according to the USDA.

Which Is Better for Heart Health?

For heart health, fish oil may have a slight edge. The AHA recommends 250–500 mg of EPA and DHA daily for healthy adults, a target easily met with fish oil supplements. A 2020 study in *JAMA Cardiology* found that high-dose omega-3 supplements reduced heart disease risk by 25% in high-risk patients. Cod liver oil, while beneficial, carries a higher risk of vitamin A toxicity if taken in excess. The National Institutes of Health (NIH) warns that long-term use of more than 10,000 IU of vitamin A daily can be harmful, making fish oil a safer choice for most people.

What About Vitamin Content?

Cod liver oil’s additional vitamins may appeal to those lacking in vitamin D, which affects 40% of U.S. adults, per the NIH. However, the vitamin A content requires caution. The Institute of Medicine states that adults should not exceed 3,000 mcg of preformed vitamin A daily. Individuals taking blood thinners or with liver conditions should consult a physician before using cod liver oil, as vitamin A can interact with medications.

Are There Other Considerations?

Cost and taste also play a role. Fish oil is generally more affordable, with prices ranging from $10–$30 per bottle, while cod liver oil tends to be pricier. Some users find cod liver oil’s strong flavor less palatable. Additionally, sustainability matters: the Marine Stewardship Council certifies sustainable fish oil sources, whereas cod fishing practices vary by region.

What Do Experts Recommend?

Dr. Sarah Ballantyne, a board-certified physician and author, advises prioritizing fish oil for heart health unless a vitamin D deficiency is confirmed. “Cod liver oil can be useful for short-term vitamin D support, but long-term use requires monitoring,” she says. The AHA emphasizes that supplements should complement, not replace, a diet rich in fatty fish like salmon or trout.

For most people, fish oil offers a balanced, well-researched option for heart health. However, those seeking additional vitamins or dietary support may find cod liver oil beneficial—provided they adhere to recommended dosages and consult a healthcare provider.