Omega-3 in dogs and cats: Why does the source matter clinically?
- Ecommercy
- 2026-09-21
- 15:46
- 0 comments
Omega-3 fatty acids are now among the most commonly used supplements in dogs and cats. They are included in recommendations for dermatological, orthopaedic, nephrological and cardiology patients, and are also used as nutritional support in oncology and during growth. However, the term “omega-3” alone tells us very little about the actual value of a supplement. In clinical practice, what matters most is which fatty acids are actually being provided, where they come from, and whether the amount supplied is appropriate for the intended purpose.
This is the focus of the webinar “Omega-3 in dogs and cats: Why does the source matter clinically?” The material covers the key facts about EPA, DHA and ALA, explains the differences between various sources of omega-3 fatty acids, and highlights the factors that should be considered when choosing a supplement for an individual patient.
Training material for vets
Where are omega-3 fatty acids used?
EPA and DHA have a wide range of applications in clinical nutrition. In dermatology, they are used in patients with skin conditions and poor coat quality. In orthopaedics, they may form part of the nutritional management of animals with osteoarthritis. They also play an important role in nephrology, where appropriately selected omega-3 fatty acids are frequently incorporated into the diets of patients with chronic kidney disease. The webinar also discusses their supportive use in cardiology and oncology, as well as the importance of DHA for the development of the nervous system and retina in puppies and kittens.
In practice, simply recommending an “omega-3 oil” is therefore not enough. The source should be selected according to the clinical indication, the other components of the diet and the patient’s health status.
Fish oils – the best-studied source of EPA and DHA
Marine fish oils remain the most commonly used source of EPA and DHA. In practice, these include salmon oil as well as products derived from smaller fish such as anchovies, herring and mackerel. Fish oils have the largest body of evidence supporting their use in dogs and cats, including in dermatology and orthopaedics.
Their main limitation is their susceptibility to oxidation. EPA and DHA are highly sensitive to oxygen, light and temperature. For this reason, not only the composition of the product matters, but also its packaging, storage conditions and the length of time it has been open. A dark bottle, limited exposure to air and an appropriately sized container are not merely marketing features – they can have a genuine impact on product stability.
Cod liver oil is not always the best option
Cod liver oil also provides EPA and DHA, but at the same time it is a rich source of vitamins A and D. This is an important difference compared with standard fish oils.
If the aim is to achieve a specific intake of EPA and DHA, increasing the amount of cod liver oil may also result in excessive intake of fat-soluble vitamins. It should therefore not be regarded as a universal source of omega-3 fatty acids, particularly in patients where total vitamin D intake needs to be carefully controlled. The webinar highlights, among other considerations, the need for caution when using cod liver oil in patients with kidney disease.
Krill and algae – alternative sources of omega-3
The webinar also discusses krill oil. Its EPA and DHA are primarily bound to phospholipids, and it additionally contains astaxanthin, which has antioxidant properties. However, krill oil is more expensive and has been studied far less extensively in dogs and cats than conventional fish oils, so its use should be assessed on an individual basis.
Microalgae oils are also becoming increasingly common. One of their major advantages is that they can be used in animals where fish-derived ingredients need to be avoided, for example in certain elimination diets. However, it is important to consider the fatty acid profile of the individual product. Some algal products contain predominantly DHA, with substantially lower levels of EPA than conventional fish oils. Therefore, if the aim of supplementation is to achieve a specific EPA intake, the fact that a product simply contains “omega-3” is not sufficient.
EPA and DHA matter more than the number of millilitres of oil
One of the most practical conclusions from the webinar is the importance of reading supplement labels carefully. Two products marketed as omega-3 oils may provide very different amounts of EPA and DHA.
If a supplement is used solely to complement a properly balanced diet in a healthy animal, the manufacturer’s recommended dosage may provide a sufficient point of reference. The situation is different when omega-3 fatty acids are intended to serve a specific nutritional purpose in a patient. In such cases, the actual amount of EPA and DHA supplied per kilogram of body weight becomes more important than the volume of oil administered. This is also particularly relevant for animals that require restriction of total dietary fat intake.
Supplement quality matters clinically
Omega-3 fatty acids are susceptible to oxidation, so when assessing a supplement, it is important to consider not only the declared EPA and DHA content, but also how the product is protected from light and oxygen, whether antioxidants are present, and whether information on raw material quality is available.
The webinar discusses oxidation indicators, including TOTOX, as well as testing for contaminants such as heavy metals, dioxins and pesticides. Transport and storage conditions are also important. Even a high-quality oil may deteriorate if it is exposed to high temperatures, light or frequent contact with air for extended periods.
For this reason, buying a very large container is usually not the best option for a small dog or cat. The supplement should be used within a period that allows it to maintain appropriate quality.
There is no single “best” omega-3 oil
The key takeaway from the webinar is simple: omega-3 products are not all the same. Fish oil, cod liver oil, krill oil, algal oil and plant oils differ in their composition, fatty acid profiles, stability and potential applications.
The choice of product should therefore depend on what we aim to achieve for the individual patient. A healthy animal may require a different source from a patient with kidney disease, a dermatological condition or one requiring an elimination diet. When omega-3 fatty acids are used for a clinical purpose, a standardised EPA and DHA content, transparent composition and overall product quality are particularly important.
A detailed discussion of the different sources of omega-3 fatty acids, their applications and limitations, and the principles of selecting an appropriate supplement is available in the webinar “Omega-3 in dogs and cats: Why does the source matter clinically?”