Cod liver oil is one of the most traditional nutritional supplements in Northern Europe. In countries like Norway, its consumption has been part of the culture for generations, especially in winter when sun exposure decreases and with it, the cutaneous synthesis of vitamin D.

Nowadays, this supplement has regained relevance both in the clinical field and in general wellness, primarily due to its unique composition: it combines long-chain omega-3 fatty acids with fat-soluble vitamins A and D.

This combination is precisely what sets it apart from other supplements and makes it an interesting tool within a well-designed nutritional strategy.

Not all omega-3s are the same, and understanding their origin is fundamental to making the right choice.

It is important to differentiate Cod Liver Oil from a conventional omega-3 supplement.

Omega-3s are essential fatty acids, meaning the body cannot produce them in sufficient quantities and they must be obtained through diet or supplementation.

The most important from a clinical point of view

Thanks to its combination of omega-3 and fat-soluble vitamins, its potential benefits span multiple body systems.

In the cardiovascular realm, cod liver oil shares the benefits typical of long-chain omega-3s.

A meta-analysis published in EClinicalMedicine in 2021 showed that omega-3 supplementation is associated with a reduction in major cardiovascular events, although the magnitude of the benefit depends on the dose used, the duration of treatment, and the patient's risk profile.

From a physiological standpoint, EPA helps decrease the production of inflammatory mediators derived from arachidonic acid and can influence cell membrane stability and endothelial function. In addition to its structural role, DHA also participates in the regulation of plasma triglycerides.

Recent reviews published in Frontiers in Nutrition suggest that to reach an omega-3 index equal to or greater than 8% (a value associated with lower cardiovascular risk), between 1000 and 1500 mg daily of EPA plus DHA for at least twelve weeks might be required.

One of the most relevant differences compared to conventional omega-3 is the supply of vitamin D.

This vitamin actually acts as a hormone, regulating the intestinal absorption of calcium and phosphorus, which are fundamental for bone mineralization. Additionally, it is involved in modulating the immune system and in regulating inflammatory and metabolic processes.

In contexts of low sun exposure, such as at high latitudes or during winter, cod liver oil can help prevent suboptimal vitamin D levels.

The vitamin A present in this oil also plays a role in immunological function and the integrity of mucous membranes, acting as a first line of defense against pathogens. However, unlike vitamin D, preformed vitamin A can accumulate in the body and cause toxicity if consumed in excess, so its dosage must be carefully considered, especially in pregnant women.

Cod liver oil has also been researched for its possible impact on eye health.

Studies published in Investigative Ophthalmology & Visual Science have explored the association between its consumption and a lower risk of glaucoma. The potential mechanism would include neuroprotective and anti-inflammatory effects of DHA, in addition to the essential role of vitamin A in the visual cycle and in the function of retinal photoreceptors. Considering that DHA constitutes a significant proportion of the fatty acids present in the retina, its adequate availability is physiologically relevant.

Beyond plasma lipids, cod liver oil has been studied in relation to inflammatory markers. A prospective study published in the Journal of the International Society of Sports Nutrition found that people who regularly consumed this supplement had lower levels of C-reactive protein, a marker widely used in clinical practice to assess systemic inflammation. Although this type of observational study does not allow for the establishment of direct causality, it does suggest a possible association between regular consumption and a lower baseline inflammatory load, which could have implications for chronic inflammatory diseases.

Another area of growing interest is mental health.

A large population study conducted in Norway and published in the Journal of Affective Disorders found that people who consumed cod liver oil regularly had fewer symptoms of depression compared to those who did not. Although a direct causal relationship cannot be established, it has been proposed that vitamin D could influence the regulation of neurotransmitters like serotonin and that omega-3s could modulate inflammatory processes involved in the pathophysiology of depression.

These findings are promising, but they do not replace established medical treatments.

It is not about one supplement being better than another, but about choosing based on the context.

Regarding quality and purity, brands such as Nordic Naturals have distinguished themselves by using fish from cold waters, their fishing is sustainable and responsible, and they carry out purification processes that seek to minimize contaminants such as heavy metals, in addition to offering formulations in the natural triglyceride form, which favors bioavailability over ethyl ester presentations.

The quality of the supplement is key to obtaining real benefits.

Some important aspects to consider:

1. Actual amount of EPA + DHA declared on the nutritional table (not just mg of oil)

2. The source from which the omega-3 is extracted; verify this in the supplement's ingredients.

3. Chemical form (triglycerides vs. ethyl ester)

4. Purity certification (heavy metals)

Choosing a good supplement can make a significant difference in its effectiveness.

Cod liver oil is not simply “omega-3.” It is a hybrid supplement that integrates essential fatty acids with fat-soluble vitamins like A and D, which are key for bone, immune, and eye health.

Scientific evidence supports moderate cardiovascular and inflammatory benefits associated with omega-3s, while the presence of vitamins A and D can offer additional advantages in certain nutritional contexts.

As with any health intervention, the choice must be individualized according to each person's nutritional status, therapeutic goals, and profile.

1. Combines omega-3 (EPA and DHA) with vitamins A and D

2. Differs from conventional omega-3 due to its nutritional profile

3. Can provide benefits for cardiovascular, immune, and bone health

4. Its choice depends on context and individual needs

5. The quality of the supplement is key to its effectiveness

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