5 evidence-based health benefits of cod liver oil

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

Cod liver health benefits include:

1. A source of vitamin D
2. May support heart health
3. May reduce anxiety and improve mood
4. May enhance memory
5. May help alleviate the 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 discover more food sources of omega-3 fatty acids.

Nutritional profile of cod liver oil

A 1,000mg serving of cod liver oil provides approximately:

• 80mg EPA
• 90mg DHA
• 800µg vitamin A
• 5µg vitamin D

The exact composition will vary by brand, the above figures are representative of a popular off the shelf brand available in the UK.

Top 5 health benefits of cod liver oil

1. A source of vitamin D

Cod liver oil is a natural source of vitamin D, which is required to help the body absorb calcium, a vital bone mineral. As such, adequate vitamin D and efficient calcium utilisation may help to reduce age-related bone loss. Vitamin D also plays an important role in supporting the immune system and regulating inflammation.

2. May support heart health

The star ingredient in cod liver oil are the omega-3 fatty acids, these are a heart-friendly polyunsaturated fat. They are referred to as an essential fatty acid because the human body is unable to make them, so it’s vital that we get these fats from our diet. Omega-3 fatty acids offer many health benefits and 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 supplementation has a preventative effect. Current dietary advice endorses the value of eating fish to help prevent heart disease, with the NHS recommending two portions of fish per week, one of which should be an oily variety such as salmon, mackerel, herrings or trout.

3. May boost mood

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 experienced fewer depressive symptoms. Furthermore, a clinical trial of medical students showed that supplementation with omega-3 fatty acids lowered inflammation and resulted in less anxiety over a 12-week period.

With that 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.

4. May enhance 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.

5. May be beneficial for rheumatoid arthritis

Thanks to the anti-inflammatory effects of both omega-3 fatty acids and vitamin D, it appears that cod liver oil may be of benefit to those with rheumatoid arthritis – by helping to reduce morning stiffness and alleviate joint 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 rheumatoid arthritis than those who never or only rarely ate oily fish.

Is cod liver oil safe for everyone?

Ideally, we should obtain our omega-3 fatty acids from our diet and the NHS recommends that we eat two portions of fish per week of which one should be the oily variety, this should provide about 450mg of EPA and DHA per an adult daily dose. Those with an allergy to fish or who follow a vegetarian or vegan diet should look to alternative plant sources of these essential fatty acids.

As a supplement, omega-3 fatty acids are 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 supplement, discuss this with your health practitioner first, especially if you are taking prescription medication, including blood thinners.

Supplements provide a concentrated and often more convenient dose of omega-3 fatty acids 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.

The NHS advises against taking cod liver oil during pregnancy because high levels of vitamin A may cause risk to the developing foetus. It is best to speak to your GP about your options.

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

Overall, is cod liver oil good for you?

For most people, cod liver oil may be a useful supplement to add to the 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. What's more, cod liver oil is packed with vitamin D so it may support those at risk of low levels of this vitamin.

However, it is always better to obtain these beneficial nutrients through the diet by eating the recommended two portions of fish per week. If you have a fish allergy, are pregnant or breast-feeding, on certain medications such as blood thinners, have high levels of vitamin A or calcium then you should consult your healthcare provider before supplementing.

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
What are the benefits of oily fish?
Top 10 sources of omega-3
Are sardines healthy?
How can I buy fish sustainably?
More healthy fish recipes
Best omega-3 supplements

This article was last reviewed on 13^th August 2024 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 urbanwellness.co.uk.

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