Summary: Cod liver oil was our grandparents' star supplement, and science proves them right. It is an exceptional natural source of omega-3, vitamin D, and vitamin A. Here, we explain what it really is, its proven benefits, how to take it, and how it differs from over-the-counter omega-3 supplements.
Table of Contents
What is Cod Liver Oil?
Cod liver oil is, as its name suggests, the oil extracted from the liver of cod (Gadus morhua). It has been used as a dietary supplement for centuries in Nordic countries, and in Spain, it was a common remedy grandmothers gave to children to prevent illnesses.
What makes it special compared to other fish oils is that, in addition to omega-3 fatty acids, it contains high concentrations of vitamins A and D naturally, without the need for artificial additives.
Nutritional Composition
Per tablespoon (5 ml) of cod liver oil:
| Nutrient | Amount | % Daily Value |
|---|---|---|
| Calories | 40 kcal | 2% |
| Omega-3 (EPA) | 890 mg | — |
| Omega-3 (DHA) | 580 mg | — |
| Vitamin A | 1,350 μg (4,500 IU) | 150% |
| Vitamin D | 10 μg (400 IU) | 200% |
| Vitamin E | 1 mg | 7% |
Science-Backed Benefits
1. Source of Vitamin D
Vitamin D deficiency is an epidemic in Spain (it's estimated that 40-60% of the population has insufficient levels). Cod liver oil is one of the richest natural sources of vitamin D, essential for bones, the immune system, and mood.
2. Anti-inflammatory Omega-3
The EPA and DHA fatty acids in cod liver oil have documented anti-inflammatory effects. Studies show benefits for cardiovascular health, cognitive function, and triglyceride reduction.
3. Bone Health
The combination of vitamin D (facilitates calcium absorption) and omega-3 (reduces bone inflammation) makes cod liver oil an ally for bone health, especially in older people.
4. Vitamin A for Vision and Skin
The vitamin A (retinol) in the oil is essential for night vision, skin health, and immune system function.
5. Child Development
DHA is crucial for brain and visual development in children. That's why grandmothers were right to give it to children (even if the taste wasn't appealing).
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Difference from Omega-3 and Fish Oil
| Characteristic | Cod Liver Oil | Fish Oil (Omega-3) |
|---|---|---|
| Origin | Cod liver | Body of various fish (sardine, anchovy, salmon) |
| Vitamin A | High (natural) | Minimal or absent |
| Vitamin D | High (natural) | Minimal or absent |
| Omega-3 | Moderate-high | High (concentrated) |
| Primary use | Natural multivitamin | Concentrated omega-3 supplement |
In summary: if you are looking for only concentrated omega-3, fish oil is a better option. If you are looking for a complete natural supplement with omega-3 + vitamin D + vitamin A, cod liver oil is superior.
How to Take Cod Liver Oil
Available Formats
- Liquid: the traditional format. Today it is sold with flavors (lemon, orange) to mask the original taste.
- Capsules: tasteless, easy to take. Currently the most popular option.
Recommended Dosage
The usual dose is 1 teaspoon (5 ml) per day or its equivalent in capsules (1-2 capsules depending on the brand). It is advisable to take it with food to improve absorption.
Best Time
With breakfast or lunch. The fat from the meal helps absorb fat-soluble vitamins (A and D).
Contraindications and Precautions
- Excess Vitamin A: as it contains a lot of vitamin A, it should not be combined with other vitamin A supplements. An excess can be toxic.
- Pregnancy: consult with a doctor. Excessive vitamin A can be teratogenic. Many doctors prefer omega-3 supplements without vitamin A during pregnancy.
- Anticoagulants: omega-3 has a mild anticoagulant effect. Consult if you are taking anticoagulant medications.
- Children: children's doses are smaller. Consult with a pediatrician.
Note: this article is for informational purposes only and does not substitute medical advice. Consult your doctor before starting any supplementation.
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Vitamin D in Cod Liver Oil
Cod liver oil is one of the most concentrated natural dietary sources of vitamin D. A teaspoon (5 ml) provides about 10 μg (400 IU), an amount difficult to obtain through a typical diet, as very few foods naturally contain vitamin D.
This fat-soluble vitamin participates in calcium absorption, bone maintenance, and normal immune system function. In countries like Spain, where a significant portion of the population has insufficient levels—especially in months with less sun—dietary sources of vitamin D become relevant.
It is important to note that the vitamin D in cod liver oil comes with a high amount of vitamin A, also fat-soluble. Therefore, it is not advisable to combine it with other vitamin A supplements or exceed the dosage indicated on the package, as both vitamins accumulate in the body.
Vitamin D requirements vary depending on age, sun exposure, pregnancy, or certain health conditions. Before starting supplementation or adjusting the dose, it is most prudent to consult with a healthcare professional, who can assess your levels with an analysis and recommend the appropriate regimen. This guide is for informational purposes and does not replace medical advice.
Canned Cod Liver: How to Eat It
In addition to the oil, canned cod liver itself is a prized gourmet product, also known as cod foie gras. It comes in a can or tub, cooked in its own fat, and retains much of the fresh liver's nutrients: omega-3, vitamin D, and vitamin A.
Its texture is unctuous, and its flavor, mild and marine, resembles a fine seafood pâté. Unlike the oil, which is taken as a supplement, canned cod liver is enjoyed as food, usually in small quantities due to its fatty nature.
The most common ways to eat it are:
- On toasted bread: spread like pâté, with a pinch of flaked salt or a few drops of lemon.
- On a toast or canapé: accompanied by pickled onions, hard-boiled egg, or piquillo pepper.
- In warm salads: a few pieces over boiled potato or seasonal vegetables.
- With some of its own oil: using the fat from the can as dressing.
It is served cold or at room temperature, directly from the can, without needing to be cooked. Once opened, it should be kept refrigerated and consumed within one or two days. Due to its nutritional density and fat content, a small serving is enough to enjoy it.
Frequently Asked Questions
Does cod liver oil taste bad?
The traditional format has an intense fishy taste that is not pleasant for most. Modern versions flavored with lemon are much more tolerable, and capsules completely eliminate the taste problem.
Is it better than eating cod directly?
They are complementary. Eating cod provides protein, omega-3, and minerals from the fish meat. Cod liver oil provides much higher concentrations of vitamins A and D. Ideally, both.
Can it be given to children?
Yes, in age-appropriate doses (generally half a teaspoon or less). Consult your pediatrician for the specific dose. It is an excellent source of vitamin D for children.
Does it have enough omega-3?
It has approximately 1.5 g of omega-3 (EPA+DHA) per teaspoon, which covers the recommended daily intake. If you need high therapeutic doses of omega-3, a concentrated fish oil supplement may be more suitable.
Can it be taken all year round or only in winter?
It can be taken all year round. In winter, it is especially useful for vitamin D (less sun exposure). In summer, if you are regularly exposed to the sun, vitamin D supplementation may be unnecessary.
Related guides
- Omega 3 in fish: ranking of the richest
- Canned sardines: types, brands, and nutrition
- Where to buy quality cod
- 15 recipes with desalinated cod
Cod is much more than liver oil. Discover our selection of premium desalinated cod from Iceland and omega-3 rich smoked salmon at Bacalalo.
