Cod liver or cod liver oil ?! Never!
That’s what many people say when I bring it up, with a disgusted grimace to match.
To be honest, I was one of those people until recently. I had a very unpleasant experience with cod liver and thought I hated the product.
But recently, I had my vitamin A levels tested — and they were very low. Before jumping into supplements, I decided to give cod liver another try… and I loved it!
This article aims to present the benefits of cod liver and its oil, and to give you some tips on how to incorporate it into your daily routine.
The benefits of cod liver
Cod liver is known for its rich nutritional profile, particularly its high content of vitamin A.
Cod liver and vitamin A
Vitamin A plays a role in bone growth, eye health, mucosal integrity (including the gut lining), skin health, and immune function (Czarnewski et al., 2017). It also helps with the absorption of certain nutrients, notably iron and vitamin D. In fact, vitamin D needs retinoic acid (a derivative of vitamin A) to activate the genes it regulates.
Only animal products, such as animal liver (with cod liver oil leading the way), ghee/butter, and dairy products (in smaller amounts), provide vitamin A in its active form (retinol).
100 g of canned cod liver provides 4,170 µg of retinol. In comparison, a 30 g serving of goat cheese contains 143 µg of retinol (source: CIQUAL). The daily nutritional reference intakes are 750 µg for men and 650 µg for women.
Beta-carotene vs. Retinol
Nowadays, most of our vitamin A comes from beta-carotene found in plant foods like carrots, sweet potatoes, spinach, and peppers.
However, the conversion of beta-carotene into active vitamin A (retinol) depends on several factors: optimal levels of vitamin C, iron, and iodine; the absence of certain genetic polymorphisms (Leung et al., 2009); and proper thyroid function. That’s why it’s beneficial to get some preformed vitamin A directly from food.
Vitamin A deficiency is common among adults (Maggini et al., 2018). Because too much vitamin A can be harmful, you can safely eat one can of cod liver every 10–14 days. If you want to consume it more often, it’s best to get your blood levels tested
Cod liver, vitamin A & pregnancy
Vitamin A deficiency is associated with an increased risk of newborn mortality within the first month of life (Kathleen & Janice, 2017). However, cod liver is not recommended during pregnancy. That’s why testing your vitamin A levels before conception is highly recommended.
Cod liver and vitamin D
Cod liver is the only food containing a non-negligible amount of vitamin D. However, eating cod liver alone won’t cover your daily vitamin D needs — personalized supplementation is still essential.
Cod liver and omega-3 EPA/DHA
Cod liver is very rich in EPA and DHA, the omega-3s with numerous benefits (brain health, microbiome support, hormonal balance, immune function…).
In fact, 100 g of cod liver provides 3 g of EPA and 4 g of DHA. The recommended daily intake is 500 mg to 1 g — a little more doesn’t hurt;
Heavy metals and cod liver
While cod liver isn’t a major source of mercury compared to other fish (like tuna, salmon, or shark), there is still a risk of contamination, depending on factors such as:
- Age and size of the fish: Older and larger fish tend to accumulate more mercury.
- Food chain position: Predatory fish higher up in the food chain accumulate more mercury than smaller, less carnivorous fish.
Cod liver, like other fish-derived products, may contain trace amounts of mercury, but usually much less than large predator fish.
How to eat cod liver
Honestly, just as is — it’s delicious (in my opinion). The texture might bother some people because it’s very soft, but that also makes it easy to spread.
You can season it with fresh herbs or spices to make a spread, or add it to a seafood risotto.
References
Brodziak-Dopierała, B., Fischer, A., Chrzanowska, M., & Ahnert, B. (2023). Mercury exposure from the consumption of dietary supplements containing vegetable, cod liver, and shark liver oils. International journal of environmental research and public health, 20(3), 2129.
Czarnewski, P., Das, S., Parigi, S. M., & Villablanca, E. J. (2017). Retinoic acid and its role in modulating intestinal innate immunity. Nutrients, 9(1), 68.
Leung, W., Hessel, S., Meplan, C., Flint, J., Oberhauser, V., Tourniaire, F., Hesketh, J., Von Lintig, J., & Lietz, G. (2009). Two common single nucleotide polymorphisms in the gene encoding β‐carotene 15, 15′‐monoxygenase alter β‐carotene metabolism in female volunteers. The FASEB Journal, 23(4), 1041-1053.
Maggini, S., Pierre, A., & Calder, P. C. (2018). Immune function and micronutrient requirements change over the life course. Nutrients, 10(10), 1531.