Fish Oil vs. Cod Liver Oil: Which Boosts Heart Health More?

Fish oil supplements prioritize concentrated omega-3 fatty acids to lower triglycerides, while cod liver oil provides omega-3s alongside vitamins A and D. According to EatingWell, the choice between the two depends on whether a person requires targeted cardiovascular support or a broader nutrient supplement.

Both supplements derive from marine sources and provide eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). These omega-3 fatty acids are linked to reduced inflammation and improved heart health, though their concentrations vary by product.

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

Fish oil is typically extracted from the flesh of oily fish, such as salmon, mackerel, or sardines. It is often processed to concentrate the EPA and DHA levels, according to EatingWell.

Cod liver oil is sourced exclusively from the liver of the Atlantic cod. This difference in source changes the nutrient profile. While it contains omega-3s, it also naturally includes significant amounts of fat-soluble vitamins A and D.

The primary distinction lies in the concentration. Many fish oil supplements are molecularly distilled to remove impurities and increase the potency of omega-3s. Cod liver oil remains a more whole-food-based supplement with a broader spectrum of nutrients.

Which supplement is better for heart health?

Fish oil is generally more effective for those targeting specific heart-health goals, such as lowering high triglyceride levels. EatingWell reports that fish oil supplements often provide higher doses of EPA and DHA per capsule than cod liver oil.

Omega-3s support the heart by reducing triglycerides, lowering blood pressure slightly, and decreasing the risk of arrhythmias. Because fish oil is more concentrated, users can reach therapeutic doses without consuming excessive amounts of other vitamins.

Cod liver oil still supports cardiovascular function through its omega-3 content. However, its primary advantage is the addition of vitamin D, which supports bone health and immune function, and vitamin A, which supports vision and skin health.

What are the risks associated with cod liver oil?

The presence of vitamins A and D in cod liver oil introduces a risk of toxicity that is not present in standard fish oil. Vitamins A and D are fat-soluble, meaning the body stores them in the liver and fatty tissues rather than excreting them through urine.

According to the National Institutes of Health, excessive intake of vitamin A can lead to hypervitaminosis A. Symptoms include nausea, dizziness, joint pain, and in severe cases, liver damage.

This risk is particularly high for individuals who already take a daily multivitamin. Adding cod liver oil to a regimen that already includes vitamin A and D can push the total intake beyond the tolerable upper intake level.

How should a person choose a supplement?

The decision depends on a person’s current diet and medical needs. EatingWell suggests reviewing the Supplement Facts label to compare the exact milligrams of EPA and DHA.

Those who eat a variety of fortified foods or take multivitamins should likely avoid cod liver oil to prevent vitamin overdose. Those living in northern climates with limited sunlight may find the vitamin D in cod liver oil beneficial.

Medical context regarding omega-3s has evolved. While they are widely used for heart health, the VITAL study, published in the New England Journal of Medicine, found that omega-3 supplementation did not significantly lower the incidence of major cardiovascular events in generally healthy adults. This suggests that supplements may be more beneficial for people with existing high triglycerides than for primary prevention in healthy populations.

• Choose Fish Oil: If the goal is high-dose EPA/DHA for triglyceride management or if already taking a multivitamin.
• Choose Cod Liver Oil: If the goal is a general nutrient boost including vitamins A and D and omega-3s are a secondary goal.
• Check Labels: Look for the combined total of EPA and DHA rather than the total “fish oil” weight.

Consulting a healthcare provider is necessary before starting either supplement, as omega-3s can have a blood-thinning effect and may interact with anticoagulant medications.