Cod Liver Oil vs Flax Seed Oil

The two most popular supplements are cod liver oil, and flaxseed oil, and it is often asked which is the best, and why? The answer is not straight forward...
Cod Liver Oil vs Flaxseed Oil - A Comparison

The two most popular supplements are cod liver oil, and flaxseed oil, and it is often asked which is the best, and why? The answer is not straight forward and does depend on the both the actual manufacturing of the product individual requirements. Both oils fulfil different roles in nutritional supplementation, and although they are both fatty acid supplements, they are not the same. This article will explore the differences between the two oils, so you can understand which one is most suitable for your needs.

 

Cod Liver Oil

Processing

The processing of cod liver oil makes a massive difference to the final product. Everything from sourcing of the cod, to how the oil is extracted and stored. For example, the liver of wild fish tends to be higher than that of farmed fish, and fermented extraction yields a product which contains naturally occurring vitamin A & D, whereas dry rendering extraction will require synthetic vitamins to be added post extraction. Omega-3 content is usually relatively consistent in the various products assuming they are from a reputable brand though, but we know that naturally occurring vitamins are better absorbed than their synthetic counter-parts.

bottle-of-fermented-cod-liver-oilOmega-3 content

1g of cod liver oil contains up to 310mg of omega-3 fatty acids. The most abundant are EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid), and 1g of cod liver oil can contain approximately 70-110mg of EPA and 100-140mg of DHA. These fatty acids are essential for cognitive function, reducing inflammation and maintaining a healthy cardiovascular system. These fats also assist with a number of other biological functions, and support the immune system.

Cod liver oil also contains small amounts of an omega-3 fatty acid called ALA (alpha-linolenic acid). This fatty acid also plays a part in cells signalling and metabolism, and can be converted into DHA and EPA.

Vitamins & Minerals

Cod liver oil contains significant amounts of vitamin A & D. Vitamin A is essential for sight and also fulfils a number of roles in the body, including supporting the immune system, maintaining health skin and gene transcription. Vitamin D also plays a very important role in the immune system, and also helps regulate hormones and is essential for maintaining healthy bones. With many cod liver oil supplements vitamin A & D are added post-extraction, as the extraction process itself can damage or remove these vitamins.

Adverse Effects

The main concern with cod liver oil is the accumulation of toxins in the oil, such as lead and mercury based compounds. These compounds accumulate in the food chain, which means the oil of large fish (such as cod) will contain high levels of these toxins. These toxins are known to damage the nervous system and have a negative impact on cognitive function. These toxins can also have very serious effects on developing foetuses.

Most processing methods for extracting cod liver oil do often try and remove these toxins, with minimises the risk, but there will undoubtedly still be trace amounts present in the oil.

 

Flaxseed oil

Processing

Flaxseed oil is processed very differently to cod liver oil, but this stage of the product manufacturing is just as important. Flaxseed oil can be extracted in 2 ways – heat extraction, or cold pressing.Heat extraction will produce a higher yeild of oil, but will cause some of the oil to react with the oxygen in the air, causing the fats to become oxidized and nutritionally useless. It is important to source cold pressed flaxseed oil to avoid these oxidised fats.

Omega-3 content

Per 1g of flaxseed oil, it contains 400-600mg of the omega-3 fatty acid called ALA (alpha-linolenic acid). This is significantly more ALA than cod liver oil, but, flaxseed oil does not contain any amount of EPA and DHA. However, ALA can be converted into EPA and DHA, so although flaxseed is not a direct source of EPA and DHA, it can still be considered a source of these fats.

flaxseedsOmega-6 content

1 gram of flaxseed oil can contain up to 180mg of omega-6 fatty acids. Omega-6 fatty acids are essential for the human body, but are relatively abundant in modern diets in various forms and quality. Excess omega-6 fatty acids in the body can be converted into pro-inflammatory agents, which may lead to discomfort and a number of ailments if there are a significant abundance of omega-6 fatty acids. Furthermore omega-6 fatty acids inhibit the conversion of ALA to EPA and DHA, which may reduce the amount of EPA and DHA you will receive from flaxseed oil.

Omega-9 content

1 gram of flaxseed oil will provide the body with up to 180mg of omega-9 fatty acids. These fatty acids are not considered essential as they can be created in the body from other fatty acids. It is also abundant in modern diets and is found in both animal and vegetable fats.

Vitamins & Minerals

Although flaxseeds contain a number of vitamins such as vitamin K, B-complexes and vitamin E significant quantities of these vitamins are not found in flaxseed supplements. Flaxseed also contains a number of minerals such as magnesium, zinc and potassium, but again, these are not found in any significant quantities in the supplement either. The lack of minerals and vitamins in flaxseed oil is a result of the processing method, and the majority of manufacturers do not add the vitamins and minerals back into the end product.

Other Nutrients

Flaxseed contain a phytoestrogen called lignan. Lignan is usually removed during the extraction process, but some manufacturers do add it to the oil at the end of processing. Lignan has shown remarkable anti-cancer effects (particularly against breast cancer), and also acts as an antioxidant.

 

Summary

Cod liver oil provides EPA, DHA, small amounts of ALA, and contains significant amounts of vitamins A & D. This makes is particularly beneficial for those whose diets do not provide much omega-3. There is the concern that cod liver oil may contain some harmful chemicals which can cause neurological damage, and can detrimental effects to developing fetuses. With this in mind, it is always a good idea to carefully look at how the fish oils are made, because the end products can vary dramatically. You can read a detailed comparison of fish oils here.

Flaxseed oil is a broad spectrum fatty acid supplement, and may be more beneficial for those who are on low fat diets. It provides large amounts of omega-3 fatty acid ALA as well as omega-6 and omega-9, giving your body with a diverse range of fatty acids. EPA and DHA can still be created from flaxseed oil, but it is dependent on a number of biological factors. Some flaxseed oil supplements contain lignan, which provides the additional anti-cancer and anti-oxidant support to the body, not all flaxseed will contain this though. It is most important when looking for at cod liver oil and flaxseed oil that you ensure it is processed in a way which protected the nutrients.

Images courtesy of shalommama and seandreilinger

I hope you enjoy the site, and like what we have worked hard to create, any feedback is very much welcome, after all this site is for you! Graduate of Nutrition & Food Science (Bsc) at Reading Uni.
  • mrlahey

    so both are decent, but would you say cod liver is the best? for the price, flaxseed oil is the best value (well the one in the store) so i’m more inclined to stock up on that instead of the cod liver oil. or i could get both but just take a small amount of cod liver oil, or only take it every few days?

    • Craig

      It is impossible to say which is best without looking at your diet. However, I would say that for most people cod liver oil is the best.

      There is so much variation in peoples diets and how manufacturers make the products though, that there is no easy answer.

      • Kate

        I am a vegetarian so thanks as I need to check the flaxseed oil I buy is cold pressed. It is a Blackmore’s anti inflammatory so I hope it is cold pressed, it does not say on label.

        • Hi Katie,

          I had a quick look at that product, and I don’t think its cold pressed, but more importantly, it isn’t flaxseed oil, and it isn’t vegetarian. It looks like it is made from mussels – sorry.

  • Bubbles

    A good thing to do is to compare the cod liver oil price to the amount of fish you would have to buy and eat to get the same omega 3’s. Then it makes the cod liver oil look really cheap 🙂 I do agree though, flax is amazing value in comparison and it’s also good stuff.

    • Morg

      That’s a good way to think of it. Even tins of mackerel cost a lot these days let alone salmon!

  • Donny

    Found this article while searching on Google, really informative and just what I was looking for! Will bookmark the site!

    • Morg

      Thanks Donny! 🙂

  • Alex

    I’m eating plenty of fish at the moment so I don’t need any omega supplements, but when I do take them I’ve taken both flax and cod with good results (well, maintained health/joints with no issues). Great comparison article, forwarded it to friends!

    • Craig

      Cheers Alex, glad you liked it 🙂

  • Cindy

    Thanks for the information on both sources. I like your impartial approach to explaining the facts so that we can decide for ourselves 🙂

    • Craig

      Cheers Cindy 🙂

The Health Cloud was created in December 2011 by Craig and Morg who have been friends since high school. Our focus is to educate our readers with unbiased health articles and on the side we run our own online health shop. This website is for you, so drop us a comment or send us a tweet, we always take the time to reply!