Interested in trying our FREE 7-day healthy diet plan? Click here and choose between our meat eaters, vegetarian or vegan meal plans.


What is cod liver oil?

Cod liver oil is renowned as a nutrient-dense source of vitamins and essential fatty acids. As the name suggests, it’s derived from the liver of the fish and is available as a liquid or capsule supplement. It's different in composition to fish oil, which is extracted from the body of oily varieties of fish.

Read on to discover what gives cod liver oil its health-promoting reputation, plus whether a supplement is really the best way to get these health benefits.

Cod liver health benefits may include:

1. A good source of omega-3 fatty acids, which our bodies must get from food

More like this

2. May play a role in lowering anxiety and improving mood

3. Could potentially improve memory

4. Provides vitamin D, which helps the body absorb calcium

5. Helps soothe inflammation and pain caused by rheumatoid arthritis

Discover our full range of health benefit guides. You can also explore further benefits of dietary fats and omega-3 fatty acids.

Nutritional benefits of cod liver oil

A 1,000mg serving provides approximately:

  • 144mg EPA
  • 107mg DHA
  • 800µg vitamin A
  • 10µg vitamin D

The composition of cod liver oil varies to that of fish oil – both are excellent sources of omega-3 fatty acids, but in different ratios. Cod liver oil also provides naturally occurring vitamin A and vitamin D.

Top 5 health benefits of cod liver oil

1. Supports heart health

The star ingredient in cod liver oil is omega-3 fatty acid, a polyunsaturated fat. It's known as an essential fatty acid because the human body is unable to make it, so it’s vital that we get it from our diets. The omega-3 fatty acid from fish can be broken down into two different types – eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) – which offer many health benefits, together and individually. They are known to be heart-healthy, with studies reporting that omega-3 fatty acids may help reduce triglycerides, increase healthier HDL cholesterol and lower blood pressure.

While most of the research suggests that consuming fish oil such as cod liver oil may reduce certain factors associated with heart disease, more evidence is required to confirm whether fish oil has a preventative effect. Nevertheless, current UK dietary advice remains the same: to help prevent heart disease, the NHS recommends eating two portions of fish per week, one of which should be an oily variety such as salmon, mackerel or trout.


2. Mood-boosting

Omega-3 fatty acids, specifically DHA, are important brain nutrients. Studies have shown that omega-3 fatty acid may play a role in lowering anxiety and improving cognitive function. In a large study of 21,835 participants, those who regularly consumed cod liver oil were shown to have fewer depressive symptoms. Furthermore, a clinical trial of medical students showed that supplementation of omega-3 fatty acids lowered inflammation and resulted in less anxiety over a 12-week period.

With this said, several similar studies found little or no effect of fish oils on mood, which suggests more research is required to fully understand the mechanisms behind these associations.

3. May support improved memory

There has been some positive research into the link between omega-3 fatty acids and memory. The Nutrition Journal published a paper that suggested that five weeks of daily omega-3 fatty acid intake had the potential to improve cognitive function in those aged 51-72 years old. In 2018, a systematic review found that omega-3 fatty acid supplementation generally correlated with improvements in cognition, especially in those with a low baseline level of fatty acids in their system.

4. Supports bone health

Cod liver oil is a great source of vitamin D, which is required to help the body absorb calcium, a vital bone mineral – from the gut. As such, adequate vitamin D and efficient calcium utilisation may help to reduce age-related bone loss.

5. May be beneficial for rheumatoid arthritis

Thanks to the anti-inflammatory effects of omega-3 fatty acid and vitamin D, it appears that cod liver oil may be of benefit to those with rheumatoid arthritis, helping reduce pain and potentially minimising the need for certain medications.

A study looking at the eating habits of 32,000 middle-aged women found that those who ate one or more portions of oily fish per week were 29% less likely to develop the rheumatoid arthritis than those who never or only rarely ate oily fish.

Is cod liver oil safe for everyone?

The World Health Organisation recommends eating one or two portions of oily fish a week, equivalent to 200-500mg of EPA and DHA. Those with an allergy to fish or who follow a vegetarian or vegan diet should look to alternative plant-based sources of these essential fatty acids.

As a supplement, omega-3 fatty acid is generally regarded as safe for most people, when taken in low doses (approximately 3g total fish oil per day or less). If you are considering taking a new supplement, discuss this with your health practitioner first, especially if you are taking prescription medication.

Supplements provide a concentrated and often more convenient dose of omega-3 fatty acid for those who may not be able to sufficiently cover their needs through diet. With that said, it is always preferable to attain nutrition through food and choose supplements only when additional support is needed. Most cod liver oil capsules also contain vitamin D and A, so make sure that you’re not taking any other supplements such as a multivitamin, or you may exceed the recommended amounts each day.

It should be noted that the NHS advises against taking cod liver oil during pregnancy because the high level of vitamin A may cause risk to the developing foetus. It is best to speak to your doctor about your options if you are pregnant or looking to conceive.

If you do decide to take a supplement, choose a product from a reputable company that tests its product for purity, because fish oils may contain contaminants such as mercury and dioxins.

Overall, is cod liver oil good for you?

There is plenty of evidence to suggest that cod liver oil is a healthy supplement to add to your diet. It's commonly taken to provide the body with a hit of omega-3 fatty acids – as our bodies can't make this essential nutrient, we must get it from food. What's more, cod liver oil is packed with vitamin D which helps the body to absorb calcium. The combination of vitamin D and omega-3 means it's a great choice for improving bone health or relieving joint pain. It's also believed to support memory and improve mood.

Try some omega-3 rich recipes:

Grilled mackerel with soy, lime & ginger
20-minute rice supper
Herb-crusted haddock
Tandoori trout
Tuna steaks with cucumber relish
Baked sea bass with lemongrass & ginger
Horseradish baked salmon
South Indian fish curry with chickpeas

Enjoyed this? Now read:

The health benefits of salmon
Our favourite healthy salmon recipes
More healthy fish recipes

This article was last reviewed on 26th November 2021 by Kerry Torrens.

Nicola Shubrook is a nutritional therapist and works with both private clients and the corporate sector. She is an accredited member of the British Association for Applied Nutrition and Nutritional Therapy (BANT) and the Complementary & Natural Healthcare Council (CNHC). Find out more at


All health content on is provided for general information only, and should not be treated as a substitute for the medical advice of your own doctor or any other healthcare professional. If you have any concerns about your general health, you should contact your local healthcare provider. See our website terms and conditions for more information.

Comments, questions and tips

Choose the type of message you'd like to post

Choose the type of message you'd like to post