Omega-3

Food sources

The richest sources of EPA and DHA are cold-water fatty fish — salmon, mackerel, herring, sardines, anchovies, tuna — and seafood. EPA and DHA are originally produced by marine microalgae and concentrate in the food chain through the fish that eat them. This means that the primary biological source of EPA and DHA is algae, not fish- — a relevant element for plant-based and vegan formulations.

ALA, on the other hand, is found in plant sources: flax oil and seeds, chia seeds, walnuts, hemp oil, and perilla oil. It is the form of Omega-3 accessible in vegetarian and vegan diets, with the limitation of low conversion to EPA and DHA already mentioned.

Microalgae are now a source of directly bioavailable plant-derived DHA and EPA, increasingly used in vegan formulations. Schizochytrium sp. and Nannochloropsis gaditana are the most common species for the production of DHA and EPA from controlled cultivation.

Mechanism of action and main functions

Omega-3s exert their biological functions through multiple and interconnected mechanisms:

• Structural Components of Cell Membranes — EPA and DHA incorporate into the phospholipids of cell membranes, affecting their fluidity, permeability and membrane receptor function. Phosphatidylcholine, the main membrane phospholipid, is one of the main vehicles through which DHA is incorporated into nerve and retinal cells.
• Precursors of Anti-Inflammatory Eicosanoids — EPA is a precursor of prostaglandins, thromboxanes and leukotrienes series 3 and 5, which have less pro-inflammatory activity than those derived from arachidonic acid (Omega-6). This underlies the documented anti-inflammatory effect of Omega-3.
• Precursors of Resolvins and Protectins — EPA and DHA are precursors of bioactive molecules (resolvins, protectins, maresins) involved in the active resolution of inflammation-not only its suppression, but its physiological termination.
• Regulation of Lipid Metabolism — EPA and DHA reduce hepatic triglyceride synthesis, increase fatty acid beta-oxidation, and modulate gene expression through PPAR nuclear receptors. The effect on reducing plasma triglycerides is among the strongest clinical evidence for Omega-3.
• Nervous System Development and Function — DHA makes up about 40% of the polyunsaturated fatty acids in the brain and 60% in the retina. It is essential for fetal and neonatal neuronal development, synaptic membrane fluidity and nerve signal transmission.

Key clinical evidence

With more than 50,000 scientific publications behind it, Omega-3s are among the most studied nutrients in the world. Areas with the most robust evidence include:

• Cardiovascular Health — Reduction in plasma triglycerides documented consistently with doses of 2-4 g/day of EPA+DHA. Effects on blood pressure, platelet aggregation, and cardiovascular inflammatory markers.
• Neurodevelopment — Maternal DHA is essential for retinal and brain development in the fetus and infant. The evidence in this area is among the strongest and has led to the approval of specific EFSA claims.
• Cognitive Function in the Elderly — Growing evidence on supporting the maintenance of cognitive function and reducing age-associated decline.
• Chronic Inflammation — Studies on rheumatoid arthritis, inflammatory bowel disease, and other chronic inflammatory conditions show positive effects on reducing inflammatory markers.
• Skin Health — EPA and DHA contribute to the maintenance of skin hydration and reduction of skin inflammation. Relevant in nutricosmetic formulations.

Molecular forms: comparing bioavailability

The molecular form in which EPA and DHA are found in a supplement significantly determines bioavailability-that is, the portion actually absorbed and available to tissues. It is one of the most relevant elements in formulation choice, often underestimated in favor of EPA+DHA concentration per capsule alone.

• Natural Triglyceride (TG) — the form in which EPA and DHA are naturally found in fish. Good bioavailability, acceptable stability. Unconcentrated fish oils are in this form.
• Ethyl Ester (EE — form obtained by transesterification of fish oils with ethanol. Allows concentration of EPA and DHA at high levels. Bioavailability 30-50% lower than TG in the absence of a fatty meal. Most common form in concentrated supplements for reasons of manufacturing cost.
• Re-esterified Triglyceride (rTG) — Omega-3 concentrates in the EE form are converted back to the triglyceride form. Bioavailability 20-70% higher than the EE form, considered the formulation gold standard in 2025. Higher production cost.
• Phospholipids (PLomega-3) -form in which EPA and DHA are bound to phospholipids, as in krill oil. High bioavailability, good penetration into cell membranes. EPA+DHA content per Capsules generally lower than concentrated forms. Synergy with Phosphatidylcholine present in krill oil is a formulation interest.

The concentration of EPA+DHA stated on the label is not the only parameter to consider when choosing an Omega-3 supplement: molecular form, oil freshness (peroxide index), and purity from contaminants (heavy metals, dioxins) are equally relevant to product efficacy and safety.

Plant-based sources: the answer to vegan formulations

The increasing move toward plant-based formulations has accelerated the development of algal sources of DHA and EPA. Oils from microalgae — particularly from Schizochytrium sp. for DHA and from Nannochloropsis gaditana for EPA — now offer purity and concentration profiles comparable to fish oils, with the advantage of being fully vegan, free of marine contaminants, and having a lower environmental impact than the fish supply chain.

Lichen-derived Vitamin D and Omega-3 from microalgae are now the two signature ingredients of high-functional plant-based nutraceuticals — a combination particularly relevant in formulations geared toward systemic wellness without compromising on ingredient origin.

EFSA claims approved

Omega-3s have approved EFSA claims specific to each molecule, according to EC Regulation 1924/2006:

• ALA — “ALA contributes to the maintenance of normal blood cholesterol levels” (1.5 g ALA daily)
• EPA + DHA — “EPA and DHA contribute to normal heart function” (250 mg EPA+DHA daily)
• DHA — “DHA contributes to the maintenance of normal brain function” (250 mg DHA daily)
• DHA — “DHA contributes to the maintenance of normal vision” (250 mg DHA daily)
• Maternal DHA – Visual Development — “DHA taken by the mother contributes to normal eye development in the fetus and breastfed babies” (200 mg DHA daily in addition to the recommended intake of 250 mg EPA+DHA)
• Maternal DHA – Brain Development — “DHA taken by the mother contributes to the normal brain development of the fetus and breastfed babies” (200 mg DHA daily in addition to the recommended intake of 250 mg EPA+DHA)
• High Dose EPA + DHA — risk reduction claims for blood pressure and triglycerides, approved at doses of 3 g/day, subject to specific reporting conditions

Vitamin D and Omega-3: an emerging synergy

The co-integration of Vitamin D and Omega-3 is the subject of increasing research for synergistic effects on immunity, inflammation and cardiovascular health. The VITAL study (2019, Harvard Medical School) — conducted in more than 25,000 participants — is the largest randomized controlled trial on this combination, with results that have opened new perspectives on multi-target formulations for longevity and cardiovascular prevention. The D3 + Omega-3 combination is now among the most popular in premium formulations for healthy aging.

Amino acids and Omega-3 in muscle recovery

In the context of sports performance, the combination of Omega-3 with Essential Amino Acids and Creatine is supported by growing evidence on the synergistic effect for muscle protein synthesis and reduction of post-exercise inflammation. DHA and EPA improve muscle cell sensitivity to insulin and anabolic signals, amplifying the response to protein supplementation.

High-dose Omega-3s (more than 3 g/day of EPA+DHA) may have anticoagulant effects: people on anticoagulant or antiplatelet therapy should consult their doctor before supplementing.

Always remember that it is important to consult a health care professional before starting any new supplement or treatment.