What Are Omega-3s? (Role, Benefits, Diet)

Omega-3 fatty acids play important roles in your pet's health. They are well known for their benefits in humans and are also valuable for dogs and cats. But what exactly are Omega-3s, and why are they so beneficial?

What Are Omega-3s?

Omega-3s are a group of polyunsaturated fatty acids.

Lipids, commonly known as fats, are one of the three main nutrient groups, alongside proteins and carbohydrates. They provide energy, but they also have many other functions. They play an important role in cell structure, help to regulate inflammation and are even involved in the production of certain hormones.

Many lipids contain fatty acids, which are chains of carbon atoms. Their length and chemical bonds influence how they function in the body. Fatty acids may be saturated (no double bonds), monounsaturated (one double bond) or polyunsaturated (multiple double bonds).

Omega-3s belong to the polyunsaturated fatty acid family. Their name refers to the position of the first double bond at the third carbon atom from the methyl end of the fatty acid chain.

Omega-3s are called 'essential' because the body cannot produce them on its own; they can only be obtained through diet.

The most important Omega-3s are alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA).

ALA is a precursor to EPA and DHA. The body can convert some ALA into these longer-chain fatty acids, but this conversion is limited in humans and dogs and is almost non-existent in cats. This is why direct dietary sources of EPA and DHA are generally preferred.

What Are the Benefits of Omega-3s?

In humans, Omega-3s have been extensively studied, including research into their benefits for the growth and development of the nervous system, blood pressure regulation, kidney function, coagulation, and immune and inflammatory responses.

Studies in dogs and cats have also examined the effects of Omega-3s, particularly EPA and DHA, in several areas:

• Support for coat quality and skin health in animals with pruritic or inflammatory skin conditions, with reported reductions in itching, hair loss and self-trauma;
• Docosahexaenoic acid (DHA) plays a role in the neurological development of puppies and kittens, particularly in motor skills, learning, and visual health;
• Support for joint comfort in animals with osteoarthritis, including improved mobility, reduced pain and support against cartilage degradation;
• Support for cardiovascular health, including a role in maintaining healthy blood pressure.

Where to Find Omega-3s?

Omega-3s must ultimately be obtained through the diet. Some foods are more concentrated in Omega-3s than others, such as:

Algae

Algae are the primary source of Omega-3s and can be particularly rich in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Algae form the base of the marine food chain and synthesise Omega-3s. Fish accumulate these fatty acids by feeding on microalgae or on other fish that have consumed algae, making algae the original marine source.

The production of EPA and DHA by algae is partly an adaptation to aquatic environments. These fatty acids help maintain cell membrane fluidity in cold and variable ocean conditions, supporting normal cell function.

Algae are an effective source of Omega-3s that directly provide EPA and DHA in a sustainable way that avoids some of the issues associated with overfishing and fish farming.

Fish Oil

Oily fish such as salmon, tuna, mackerel, sardines, herring and anchovies are rich sources of Omega-3s.

These marine species do not produce Omega-3s themselves. They accumulate them by feeding on algae or on other fish that have consumed algae.

Some oily fish can accumulate pollutants and heavy metals such as arsenic, mercury, lead and cadmium. Levels vary according to species, origin and position in the food chain, which is why quality controls are important.

Farmed fish are not guaranteed to be free of heavy metals or pollutants because their feed may contain ingredients derived from wild-caught fish. Testing by the French consumer organisation 60 Millions de Consommateurs found mercury levels seven times higher in the sampled farmed organic salmon than in the sampled wild salmon.

Furthermore, some species used as sources of Omega-3 are affected by overfishing, which can disrupt marine food chains. Salmon is one example. Fish farming does not eliminate pressure on biodiversity because some farmed fish are fed marine ingredients, including krill, which is also subject to fishing pressure.

Overfishing and climate change may also affect Omega-3 levels in fish. Recent studies by Lloret et al. and Meyer et al. have reported a significant decrease in Omega-3 concentration in wild fish.

Green lipped mussel

Unlike oily fish, the green-lipped mussel (Perna canaliculus) is a sustainable, environmentally responsible source of Omega-3s. Its farming in New Zealand takes place in protected marine areas, subject to strict quotas to preserve the ecosystem.

Green-lipped mussels are farmed using suspended lines and feed naturally on phytoplankton, without added feed. They filter seawater without disturbing the seabed and accumulate nutrients from marine microalgae, including antioxidants and fatty acids.

The result: a pure, traceable Omega-3 source with a low ecological footprint, with good bioavailability for dogs.

Antarctic krill

Antarctic krill oil (Euphausia superba) is valued because it supplies Omega-3s in phospholipid form, which can be readily incorporated into cell membranes.

Despite this biological advantage, krill harvesting today raises major environmental concerns.

Krill is an important part of the Antarctic food chain and a major food source for whales and other marine species. Overfishing, driven partly by demand for aquaculture feed and dietary supplements, can place additional pressure on an ecosystem already affected by climate change and melting sea ice.

In summary, although krill provides bioavailable Omega-3s, its use raises significant environmental questions.

Oilseeds: seeds and vegetable oils

Oilseeds such as chia, hemp, walnuts, flaxseed and rapeseed, whether consumed as seeds or oils, are rich in alpha-linolenic acid (ALA), but do not contain eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA).

ALA is an Omega-3 precursor that the body can use to synthesise EPA and DHA. However, the conversion of ALA to EPA+DHA is generally not very efficient, which is why direct dietary sources of EPA and DHA may be preferable when these fatty acids are specifically required.

Dietary supplements

An Omega-3-rich dietary supplement can help complement the diet by providing concentrated fatty acids. Dogs and cats may use supplements to meet specific nutritional needs and support their wellbeing.

Omega-3 supplements are available in several forms, including marine oils and plant-based products, but they differ in quality, safety and fatty acid content.

The most beneficial Omega-3s for animal health are eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), but they are difficult to synthesise from alpha-linolenic acid (ALA), which is why it is preferable to prioritise direct sources of EPA and DHA.

However, some sources of EPA and DHA, including salmon and krill oils, may be associated with fishing pressure and can contain environmental contaminants if they are not adequately controlled.

Before giving your pet a dietary supplement, check that each batch has undergone release testing for contaminants such as heavy metals and pollutants. The label should also clearly state its nutritional composition, including EPA and DHA levels and any other clinically documented ingredients.

Conclusion

Omega-3s are more than supplement ingredients: they are an important part of canine nutrition. They contribute to the health of the skin, coat, nervous system and joints, among other physiological functions.

Dogs may receive insufficient long-chain Omega-3s, particularly when their diet is relatively high in Omega-6. By incorporating natural, quality-controlled sources of EPA and DHA, derived from algae, fish or green-lipped mussel, you can help support a balanced diet and normal body functions.

In short, an appropriate Omega-3 intake can help support your dog's long-term health and mobility.

Scientific references

• Magalhães TR, Lourenço AL, Gregório H, Queiroga FL. Therapeutic Effect of EPA/DHA Supplementation in Neoplastic and Non-neoplastic Companion Animal Diseases: A Systematic Review. In Vivo. 2021 May-Jun;35(3):1419-1436. doi: 10.21873/invivo.12394. Epub 2021 Apr 28. PMID: 33910819; PMCID: PMC8193331.
• Lloret, J., Vila-Belmonte, M., Izquierdo, A., San, J., Biton-Porsmoguer, S. 2025. The unsustainability of the Omega-3 supply from seafood in the Mediterranean under global change. Food Policy 136: 102972. https://doi.org/10.1016/j.foodpol.2025.102972
• Meyer B, Arata JA, Atkinson A, Bahlburg D, Bernard K, Cárdenas CA, Grant SM, Hill SL, Hüppe L, Ichii T, Kawaguchi S, Krafft BA, Labrousse S, Maschette D, Piñones A, Reiss C, Siebenhüner B, Sylvester Z, Ziegler P. Adjusting the management of the Antarctic krill fishery to meet the challenges of the 21st century. Proc Natl Acad Sci U S A. 2025 Sep 16;122(37):e2412624122. doi: 10.1073/pnas.2412624122. Epub 2025 Sep 8. PMID: 40920918; PMCID: PMC12452838.

This article was written by the R&D team at Laboratoire Sensilia, experts in animal nutrition.