Cod Liver Oil: Are There Health Benefits?

Medically Reviewed by Kathleen M. Zelman, RD, LD, MPH on March 23, 2023
3 min read

Cod liver oil has been used for centuries as a preventative measure against vitamin D deficiency, also called rickets. Historically, people living in northern Europe have relied on cod liver oil as a vitamin D supplement during the winter months when sunlight is scarce.

The oil is extracted from the livers of Atlantic cod and then filtered for purity. The leading producers of cod liver oil supplements are northern countries like Norway and Iceland, but you can find it in most supermarkets and health food stores. People take cod liver oil capsules to help with arthritic joint pain and cardiovascular disease prevention.

Cod liver oil is an excellent source of vitamin A and vitamin D. Vitamin A is a vital nutrient for immune system function, cellular growth, eye health, and reproduction. It’s also rich in omega-3 fatty acids, which decrease blood clot formation and reduce inflammation in the body. 

Even more so, cod liver oil’s high vitamin D content is what distinguishes it from other fish oils. Scientists estimate that over a billion people worldwide are vitamin D deficient or insufficient.

Vitamin D deficiency is linked to bone fractures in the elderly and abnormal brain development in offspring. It may also lead to the development of metabolic syndrome, which involves the combination of high blood pressure, high glucose levels, and high cholesterol. This can contribute to coronary heart disease, diabetes, and cancer.

One tablespoon of cod liver oil contains: 

  • Calories: 123
  • Protein: 0 grams
  • Fat: 14 grams
  • Carbohydrates: 0 grams
  • Fiber: 0 grams
  • Sugar: 0 grams

Cod liver oil is a good source of: 

Cod liver oil is a good source of the omega-3 fatty acid known as docosahexaenoic acid (DHA). Studies have shown that DHA improves cognitive function and can protect against Alzheimer’s disease and dementia.

Consuming cod liver oil can provide you with a significant amount of essential vitamins and fatty acids. Supplementing with it may offer several potential health benefits:

Glaucoma Prevention and Treatment

Glaucoma is a leading cause of blindness. The vitamin A found in cod liver oil prevents cellular damage from oxidation, which contributes to the development of glaucoma. Vitamin A also prevents deterioration of eye structure.  

The omega-3s in cod liver oil offer even more significant effects. Fatty acids like DHA and EPA lower pressure and increase blood circulation in the eye, which helps stall the progression of glaucoma. 

Anti-Cancer Properties

Because cod liver oil contains both vitamin A and omega-3 fatty acids, it’s a powerful weapon in fighting cancer. It not only displays anti-inflammatory properties, which help prevent cancer cell development, but it could also be used to treat cancer.

Cancerous tumors need to create new blood vessels to grow, a process called angiogenesis. Cod liver oil prevents angiogenesis and disrupts cancer cell reproduction, interfering with tumor growth.

Multiple SclerosisPrevention

Low vitamin D levels have been linked to multiple sclerosis (MS). One study found that people who had consumed cod liver oil during their adolescent years had a lower risk of developing adult-onset MS. 

Rheumatoid Arthritis Management

The anti-inflammatory effects of cod liver oil have been shown to help people with rheumatoid arthritis cope with joint pain. A 24-week study found that people who supplemented with cod liver oil reported lower pain scores. There was also a marked decrease in painkiller doses needed to manage pain. 

There are a few minor risks associated with cod liver oil. You should consult with your doctor before taking it or any other supplement. Consider the following before consuming cod liver oil:

Pregnancy Concerns

Cod liver oil may help pregnant women get adequate amounts of vitamin D. However, some experts have cautioned against taking cod liver oil supplements during pregnancy because high vitamin A levels can harm the unborn baby.

Medication Interference

Avoid cod liver oil if you are on blood thinners like Warfarin. It can increase the blood-thinning effects of the medication, leading to dangerous levels of bleeding.


It should be noted that both vitamins A and D are fat soluble and can be potentially toxic in high doses.