Fish Oil

What is fish oil?

Fish oil is obtained from the tissues of oily fish and is a concentrated source of the long-chain omega-3 fatty acids EPA and DHA. Common sources include anchovies, sardines, mackerel, herring and salmon.

EPA stands for eicosapentaenoic acid, while DHA stands for docosahexaenoic acid. Both are incorporated into cell membranes and serve as precursors for signaling molecules.

Why are EPA and DHA important?

EPA and DHA contribute to several physiological processes. DHA is particularly abundant in the brain and retina, while EPA is strongly involved in the formation of lipid mediators that regulate inflammatory responses.

Authorized EU health claims state that EPA and DHA contribute to normal heart function when consumed in the required amount. DHA also contributes to the maintenance of normal brain function and normal vision at the specified intake.

Fish oil and cardiovascular health

Omega-3 fatty acids have been studied extensively in relation to triglycerides, blood pressure, heart rhythm and cardiovascular events.

Higher doses of EPA and DHA can reduce elevated triglyceride levels. However, the effect of standard fish-oil supplements on the prevention of heart attacks or strokes varies between studies and depends on dose, formulation and patient population.

Prescription omega-3 medicines should not be confused with regular food supplements.

Fish oil and inflammation

EPA and DHA can be converted into resolvins, protectins and maresins. These signaling molecules are involved in the resolution phase of inflammation.

This does not mean that fish oil acts as a general anti-inflammatory medicine. The clinical relevance depends on the condition, dose and individual fatty-acid status.

Fish oil and the brain

DHA is an important structural component of neuronal membranes. Adequate intake is particularly relevant during pregnancy, infancy and childhood.

In adults, omega-3 status has been investigated in relation to mood, cognitive function and neurodegenerative disease. Evidence is mixed, and fish oil cannot be recommended as a treatment for dementia or depression without medical evaluation.

Fish oil versus plant-based omega-3

Plant foods such as flaxseed, chia seeds and walnuts contain alpha-linolenic acid, or ALA. The body can convert ALA into EPA and DHA, but conversion is limited.

People who do not consume fish may use algae oil as a direct plant-based source of DHA and, depending on the product, EPA.

Quality criteria

High-quality fish oil should be tested for oxidation, heavy metals and environmental contaminants. The TOTOX value is commonly used as an indicator of overall oxidation.

The source of the fish, purification process, EPA and DHA content and storage conditions should be declared transparently.

Dosage and safety

The appropriate dose depends on dietary intake and individual health goals. People who eat oily fish several times per week may require less supplementation than those who rarely consume fish.

High doses may increase the risk of bleeding, particularly in combination with anticoagulant medication. Fish oil may also cause belching, digestive discomfort or a fishy aftertaste.

Conclusion

Fish oil is a concentrated source of EPA and DHA and may help improve omega-3 status. Its value depends on product quality, dose, dietary intake and individual laboratory values.

An omega-3 blood test can provide a more objective basis for deciding whether supplementation is useful and for monitoring changes over time.