For centuries, cod liver oil has been a go-to remedy for everything from aching joints to low energy. Passed down through generations, this golden-hued oil has stood the test of time — and for good reason. It contains essential nutrients like omega-3 fatty acids and vitamins A and D.
But in today’s world of endless health trends and supplements, does cod liver oil still live up to the hype? To learn more, we spoke with Alexandra Lessem, a family nurse practitioner with Banner Health.
What is cod liver oil?
Cod liver oil is exactly what it sounds like: oil extracted from the livers of cod fish, typically Atlantic cod.
“Unlike regular fish oil, which comes from the flesh or skin of various fish, cod liver oil contains high amounts of vitamins A and D naturally stored in the liver,” Lessem said.
These fat-soluble vitamins, combined with anti-inflammatory omega-3 fatty acids, make it a unique supplement with a broad range of health benefits.
You can find this oil in many different forms, such as capsules, gummies or liquids.
Health benefits of cod liver oil
Cod liver oil offers many health benefits. Here are some of the biggest ones:
- Supports heart health: Cod liver oil contains omega-3s (like eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)) which help lower inflammation, reducing the risk of heart disease. Omega-3s also help keep blood pressure and cholesterol levels in check.
- Boosts brain function: Your brain needs healthy fats to work well. Omega-3s in cod liver oil support brain function. They may help improve memory and focus.
- Reduces pain and inflammation: “Evidence shows that cod liver oil can be beneficial in reducing pain associated with conditions like rheumatoid arthritis and can help reduce inflammation,” Lessem said. This makes it a good option for people with joint pain or autoimmune conditions.
- Strengthen bones: Vitamin D is important for strong bones. It helps your body absorb calcium, which keeps bones from becoming weak. “Due to the high concentration of vitamins A and D, it can also be helpful for people who are deficient in those vitamins and promote strong bones,” Lessem said.
- Improves eye health: Your eyes need vitamin A to stay healthy. Cod liver oil is full of this vitamin. It may help prevent eye diseases and keep your vision sharp as you age.
- Supports immune health: No one likes to get sick. Vitamin A and D in cod liver oil can help keep your immune system strong. This can help your body fight off infections.
It is important to note that although the vitamins in cod liver oil may help fight infections, it is not medically recommended or effective treatment for measles. Your best defense against measles is making sure you are up to date on your MMR (measles, mumps, rubella) vaccine.
Are there any risks or side effects?
While cod liver oil has some benefits, it also comes with risks. Here are the most important ones to know:
- Vitamin A and D toxicity: “Since vitamins A and D are fat-soluble, they can build up in the body and lead to toxicity if too much is taken,” Lessem said. “I would not recommend people take cod liver oil without knowing their vitamin A and D levels.”
- Contamination: “The biggest risk with cod liver oil is that, since it comes from the fish's liver, there is a likelihood of ingesting toxins such as mercury, PCBs (polychlorinated biphenyls) or other contaminants which have built up in the fish’s liver,” Lessem said. Some of this risk can be reduced with purification, but likely not all.
- Overfishing: Cod is a popular fish and overfishing can be a problem. Unsustainable fishing practices can harm marine ecosystems. If you choose to take cod liver oil, look for a brand that follows sustainable fishing practices.
- Lack of regulation: “The FDA doesn’t regulate supplements, so there is always some question about their ingredients, purity and benefits,” Lessem said. Some companies may mislabel their product or include lower-quality ingredients. Always buy from a reputable brand.
- Side effects: Besides these other risks, some people may experience upset stomach, diarrhea and acid reflux. Cod liver oil can act as a blood thinner, affecting blood clotting. So if you are on blood thinners, pregnant or pre-surgery, you’ll want to check with your health care provider first.
- Taste: Traditional cod liver oil has a strong fish taste and may not be your cup of tea. There are some flavored or capsule forms to make it easier to consume.
What to look for in a high-quality cod liver oil
Not all cod liver oil is the same. As Lessem mentioned, the FDA does not regulate vitamins and supplements. She shared some tips on what to look for when buying it:
- Purity: Consumers should look for a product that is purified and comes from a reputable manufacturer, ideally with the United States Pharmacopeia (USP) seal, which indicates the product has been tested to ensure it contains what it says it does.
- Low mercury: Good brands ensure their oils are free from harmful toxins like mercury.
- Sustainable sourcing: Some companies fish in ways that protect ocean life.
- Freshness: Check the expiration date. Old oil can go bad and taste worse.
Some fish oils can give you some unpleasant fish burps. If this is the case, consider other fish-free ways to get your omega-3s and vitamins A and D in your diet, like walnuts, seaweed, chia seeds and mixed greens like spinach.
Takeaway
Cod liver oil remains a nutritional powerhouse that can benefit heart health, brain function, immunity and more. While it may not be the trendiest supplement on the market, its time-tested benefits make it a worthy addition to a well-balanced diet.
Remember to talk to your health care provider or a Banner Health specialist before taking any new supplement.
