Cod liver oil boasts a host of health benefits and has been used since the 18th century as a means of supplementing the body with vital vitamin D – a nutrient that nearly everyone in the UK is deficient in. But fish oil has other benefits, too.
As the name suggests, cod liver oil is extracted from the liver of cod fish, which might not sound all that appealing but there are plenty of reasons to take it.
“Cod liver oil is a popular choice because it's rich in omega-3 fatty acids, vitamin D and vitamin A, all of which support heart health, brain function, immunity and skin health,” explains nutritionist Alexa Mullane. “The omega-3 fatty acids also support cognitive performance, reduce inflammation, and may even help combat mood disorders like anxiety and depression.”
People looking to improve cardiovascular health, strengthen bones, or boost cognitive function may find cod liver oil particularly useful. However, pregnant women should avoid cod liver oil due to its high vitamin A content.
Omega 3s are found mainly in fish but they can also be found in some nuts, in algae and in flaxseed. Experts recommend consuming two portions of fish a week in order to get enough fatty acids into your diet, but this can be tricky, especially if you don’t enjoy eating fish.
Keep reading for everything you need to know about cod liver oil, including what it is, the benefits and the supplements to buy.
What is cod liver oil?
Cod liver oil is one of the most effective sources of vitamins A and D and omega-3 in one supplement. Your body can’t naturally produce some of the main components of omega-3 fatty acids, namely eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), so taking a supplement can help top up the concentration in your body to support your health.
The vitamin D in cod liver oil helps to regulate phosphate and calcium in the body which contributes to healthy muscles, bones and teeth. The body can make vitamin D when it’s exposed to sunlight, but according to experts, most people living in the UK struggle to get adequate sun exposure and are vitamin D deficient.
Vitamin A, also known as retinol, helps the body to metabolise iron and supports eye health and the quality of your skin. It’s also vital for immunity and maintaining your body’s natural defences against infections and diseases. You’ll find vitamin A in green leafy vegetables and dairy, along with some root vegetables like sweet potato and squash. It’s also in orange foods like carrots, mangoes and apricots.
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What are the benefits of cod liver oil supplements?
Cod liver oil supplements are great for anyone who struggles to maintain a balanced, vitamin-rich diet or who worries about a lack of vitamin D, but it’s also recommended to fortify the body as it naturally ages. As we grow older, our bodies face new challenges, especially in regards to things like the quality of our joints, our vision and our cognitive abilities.
Supplementing cod liver oil, which contains the powerful antioxidants A and D, can help with neutralising free radicals and encouraging new healthy cell turnover. It can also help reduce inflammation in the body. Omega-3 can suppress the proteins that cause inflammation, lessening pain and swelling, promoting a better healing process and reducing the likelihood of infections.
As we age, our bones and joints may also suffer as cartilage breaks down and bones become weaker. The vitamin D in cod liver oil can help the body absorb calcium effectively and prevent the rate of bone loss. This can lessen the risk of a serious injury if you fall and help support tooth health in later life, too. Some studies suggest that cod liver oil could also reduce joint pain and improve symptoms of rheumatoid arthritis.
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The ageing process can also affect the quality of your vision, something that vitamin A is essential for. Omega-3s have also been shown to reduce the risk of eye conditions. However, the most significant area of the body that omega-3 is shown to benefit is the heart. This is because fatty acids have the potential to reduce blood triglycerides – fat stored in the blood – and raise good cholesterol.
People of all ages could benefit from taking a cod liver oil supplement daily, but despite the many positive impacts, these supplements aren’t a substitute for a balanced diet. You should still aim to eat fish twice a week and get adequate vitamin D and A from the foods you eat.
It can be difficult to get enough omega-3 from a vegan diet, but it is possible, and fish-free supplements can be an important part of maintaining a healthy lifestyle when you decide to go plant-based.
Which fish oil should I choose?
“Cod liver oil and omega-3 supplements both provide essential fatty acids, but cod liver oil offers additional nutrients like naturally occurring vitamins A and D, which support immune function, vision, and bone health,” explains Mullane.
“Omega-3 supplements, mostly derived from fish or algae, will usually have higher levels of EPA and DHA and are often made from different types of oily fish such as sardines, anchovies and mackerel.”
Cod liver oil is considered a bit of a super supplement because it contains so many nutrients, however, there is a risk of overloading your body if you’re taking it at the same time as other supplements that contain Vitamin A and Vitamin D, so it’s worth bearing this in mind.
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“Fish oil (purely omega-3 with no added vitamins) is a great choice for heart and brain health without worrying about vitamin A toxicity or doubling up if you're already taking a vitamin D supplement,” explains nutritionist Claire Johnson.
“Cod liver oil may be useful for those needing extra vitamin A or D, but it's always worth checking this first with your GP, especially if you're trying to conceive or pregnant.”
Johnson adds that “since the liver filters toxins, cod liver oil may have a higher risk of contamination from environmental pollutants like heavy metals. To stay safe, choose a high-quality supplement. Whether you decide on cod liver oil or fish oil, choose from a reputable brand that publishes purity test results. My favourite fish oil brand is Bare Biology, which tests its products for purity and quality, with five-star purity and quality ratings from International Fish Oil Standards.”
You might also consider taking krill oil, which is also derived from fish and offers a high dose of Omega-3 fatty acids but contains astaxanthin – a powerful antioxidant that can benefit heart health.
If you’re looking for a vegan alternative to fish oil, there are many options made from algae, walnuts or flaxseeds. The nutrients in microalgae are actually consumed by the fish that make cod liver oil, and in comparison to Omega-3 alternatives made from hemp or flaxseed, the bioavailability is considered to be much better.
“If you want omega-3 benefits without the extras, go for a high-quality fish oil or algae-based supplement for a plant-based option. If you need extra vitamin A and D, cod liver oil can be a useful addition, but proceed with caution. As always, your individual needs should dictate your choice,” says Johnson.
“Cod liver oil is ideal for those seeking a broader nutrient profile, while pure omega-3 supplements may be preferable for those who need higher doses of EPA and DHA without excess vitamin A. Look for cod liver oil brands that use wild fish instead of farmed fish, sustainable practices, and are tested for purity. I like Wiley's Finest wild norwegian cod liver oil, Nordic Naturals cod liver oil, Zinzino fish oil adds Mullane.
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