Cod Liver Oil: Nutrition Facts and Health Benefits

Cod liver oil is one of the oldest and most respected dietary supplements, with a history dating back centuries. This golden oil, extracted from the liver of codfish, is renowned for its unique combination of nutrients and potential to support a variety of health conditions. Once given to children to prevent rickets, cod liver oil has resurfaced in modern nutrition science as a powerful source of omega-3 fatty acids and fat-soluble vitamins. In this article, we’ll explore the nutritional profile of cod liver oil and dive deep into its evidence-supported health benefits, making sense of both tradition and cutting-edge research.

Cod Liver Oil Nutrition Facts

Cod liver oil stands apart from other fish oils due to its distinctive nutrient composition. It’s not only a rich source of long-chain omega-3 fatty acids, but also delivers significant amounts of vitamins A and D—nutrients essential for health and often lacking in modern diets. Let’s take a closer look at what makes cod liver oil nutritionally unique.

Table 1: Key Nutrients in Cod Liver Oil

Understanding the Nutrient Content

Cod liver oil is a nutritional powerhouse, but its contents can vary between brands and batches. Here’s what you need to know:

Vitamins A and D

• Vitamin A: Cod liver oil is one of the richest natural sources of vitamin A, crucial for normal vision, immune function, and skin integrity. Traditional formulations contained up to 2,500 IU per teaspoon, but modern products might range from 700 to 1,200 IU, depending on the manufacturer’s process and whether vitamins are added back post-purification. Too much vitamin A can be harmful, especially for young children, so it’s important to check the label for exact amounts 2 4.
• Vitamin D: Historically, a teaspoon of cod liver oil provided about 400 IU of vitamin D, enough to prevent rickets in children. Modern processing may reduce this content, with some products providing as little as 1 IU and others up to 1,000 IU per teaspoon. Vitamin D is vital for calcium absorption, bone health, and immune support 2 4.

Omega-3 Fatty Acids

• EPA (Eicosapentaenoic Acid) & DHA (Docosahexaenoic Acid): These long-chain omega-3s are present in significant amounts, with typical values around 400–500 mg of each per teaspoon. EPA and DHA are essential for cardiovascular health, brain function, and inflammation control 2 5 7 8 9. Cod liver oil contains less omega-3 than concentrated fish oil capsules but surpasses them in vitamin content.

Other Nutrients

• Minor nutrients: Cod liver oil may also provide trace amounts of vitamin E and other micronutrients, but these are not present in substantial quantities compared to the headline nutrients above 2.

Factors Affecting Nutrient Levels

• Manufacturing processes: Modern cod liver oil is often purified, which can strip out natural vitamins. Some producers add synthetic vitamins back, but concentrations vary widely 4.
• Regulation: Cod liver oil is not standardized in the U.S., so actual vitamin A and D content can differ markedly between products and over time 4.
• Serving size: Nutrient values are typically given per teaspoon (about 5 ml), the most common daily dose.

Summary

Cod liver oil remains an efficient way to obtain both omega-3s and fat-soluble vitamins, especially for those who don’t eat much oily fish or have limited sun exposure. However, because nutrient content varies, consumers should always check the product label and be mindful of the potential for excessive vitamin A intake, particularly for children and pregnant women 4.

Cod Liver Oil Health Benefits

While cod liver oil’s reputation as a health tonic hails from the days of treating rickets, modern science has uncovered a much wider range of potential benefits. From immune support to heart protection, the nutrients in cod liver oil work in concert to promote health across the lifespan.

Table 2: Cod Liver Oil Health Benefits

Immune Support and Infection Prevention

Cod liver oil’s combination of vitamins A and D and omega-3s is particularly important for immune health.

• Children’s Respiratory Health: Supplementation has been shown to reduce the frequency of upper respiratory tract infections in children by 36–58%, likely due to the synergistic effects of vitamins A, D, and omega-3s on immune modulation 2 4.
• Historical Role: Cod liver oil was a primary source of vitamin D before the advent of synthetic supplements and played a major role in preventing rickets and other deficiency diseases 2 4.
• Anti-inflammatory Action: Omega-3 fatty acids in cod liver oil help regulate inflammation, a key aspect of immune function 2.

Cardiovascular Protection

• Atherosclerosis Prevention: Animal studies have found that cod liver oil supplementation can slow the development and progression of coronary artery disease, even in the presence of a high-cholesterol diet. This protective effect is not directly due to lowering cholesterol, but rather to anti-inflammatory actions and improved vascular function 1 7 8.
• Endothelial Function: Cod liver oil improves endothelium-dependent relaxation in arteries, which is vital for maintaining healthy blood flow and preventing vascular disease 8.

Diabetes Risk Reduction

• Type 1 Diabetes: Large Norwegian studies have found that both maternal use of cod liver oil during pregnancy and infant supplementation in the first year of life are associated with a significantly lower risk of developing type 1 diabetes in children. This effect is likely due to the anti-inflammatory properties of omega-3s and possibly vitamin D’s influence on immune regulation 5 6.
• Population Evidence: The protective association was seen with cod liver oil specifically, not with other vitamin D supplements, suggesting that the unique nutrient mix in cod liver oil is important 5 6.

Joint Health and Rheumatoid Arthritis

• NSAID-Sparing in RA: Cod liver oil supplementation has shown promise as an adjunct in rheumatoid arthritis. In a controlled study, 39% of patients taking cod liver oil were able to reduce their NSAID use by more than 30% over nine months, compared to only 10% in the placebo group. This demonstrates a meaningful anti-inflammatory benefit, important for chronic pain management 9.
• Mechanism: The high content of EPA and DHA helps reduce inflammation, which is central to arthritis and other chronic inflammatory diseases 9.

Eye Health and Glaucoma

• Vision Support: Vitamin A in cod liver oil is essential for normal vision and the integrity of eye tissues 3.
• Potential Role in Glaucoma: Emerging research suggests cod liver oil may help protect against glaucoma by supporting ocular blood flow, reducing intraocular pressure, and preventing oxidative damage. While more clinical studies are needed, the rationale is strong due to the combined effects of vitamin A and omega-3s 3.

Additional Considerations

• Cholesterol and Lipid Balance: In experimental studies, cod liver oil has reduced serum cholesterol and improved blood lipid profiles, particularly in models of fatty acid deficiency and hypercholesterolemia 1.
• Manufacturing and Safety: Modern cod liver oil products are generally safe when taken as directed, but dosing should be monitored to avoid excess vitamin A or D, especially in populations sensitive to fat-soluble vitamin toxicity 4.

Conclusion

Cod liver oil is a time-honored supplement, now supported by a growing body of scientific evidence. Its unique nutrient blend—rich in omega-3 fatty acids, vitamin A, and vitamin D—makes it a versatile addition to many health regimens.

Key takeaways:

• Nutrient Dense: Cod liver oil provides meaningful amounts of EPA, DHA, vitamin A, and vitamin D, but nutrient levels vary by brand and process 2 4.
• Immunity: Shown to reduce respiratory infections in children and modulate inflammation 2 4 5 6.
• Heart and Vascular Health: Slows atherosclerosis and improves blood vessel function 1 7 8.
• Diabetes Prevention: Associated with lower risk of childhood-onset type 1 diabetes when used in pregnancy or infancy 5 6.
• Joint Support: Helps reduce NSAID use in rheumatoid arthritis, supporting joint health 9.
• Eye Protection: Supports vision and may play a protective role in glaucoma 3.
• Safety: Choose products carefully and avoid excessive dosing, especially for children and pregnant women 4.

Cod liver oil’s legacy as a “natural multivitamin” is well-earned, but as with any supplement, it’s important to use it judiciously and consult with a healthcare provider for personalized advice.