As the name suggests, cod liver oil is the fat extracted from the livers of Atlantic cod and is rich in omega-3 fatty acids (DHA and EPA). Omega-3 supplements, on the other hand, are extracted from whole fish. Cod liver oil supplements, which are available over-the-counter, are also rich in vitamins A and D.

If you need therapeutic doses of EPA and DHA (thousands of milligrams of both to lower triglycerides, treat ulcerative colitis, or depression), fish oil supplements are the better choice. The amount of cod liver oil you would need to consume to get therapeutic levels of DHA and EPA would likely include excessive amounts of vitamin A, which can be toxic to your liver.

Cod get their omega-3 fatty acids from eating microscopic marine algae known as phytoplankton. Cod liver oil in supplements is either extracted from wild-caught or farmed cod. Wild-caught cod supplements claim to provide more omega-3s and fewer contaminants than supplements made from farmed cod.

Benefits

There are few studies of the health benefits of taking cod liver oil supplements. Most research focuses on omega-3 supplementation, which has been found to provide a wide range of health benefits at relatively high doses.

One study published in 2022 in the British Medical Journal found that liquid cod liver oil did not reduce the risk in winter of acute respiratory infections, including COVID-19, when compared to a placebo. A review of 28 studies found evidence that a combination of probiotics and cod liver oil supplements improved blood sugar control.

But the National Institutes of Health suggests that cod liver oil supplements may actually increase blood sugar levels. Supplementation may reduce overall inflammation, which could help with arthritis pain and have an antibacterial effect. An animal study found that cod liver oil ointment, when applied topically, accelerated wound healing.

Risks

While cod liver oil is likely safe for most adults, it could cause heartburn, stomach upset, and nausea, and could increase the risk of bleeding. If you’re taking cod liver oil supplements, check with your healthcare provider if you’re also taking anticoagulant medication, and before any surgical procedure.

Bottom line

There is little research on the health benefits and risks of cod liver oil supplements. However, taking liquid cod liver oil or supplements as directed is most likely safe for most adults.

(Reprinted with permission from Environmental Nutrition, a monthly publication of Belvoir Media Group, LLC. 800-829-5384. www.EnvironmentalNutrition.com.)

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