DHA and EPA: The Importance of Omega Fatty Acids in Dogs and Cats

Your aging pet may seem to be doing great, but aging can also bring changes that are difficult to see. Your energetic companion may become slower on walks, take longer to get comfortable after resting, or seem less responsive to familiar games and routines. Although some changes are a normal part of aging, nutrition can play an important role in supporting your pet's health and quality of life throughout their senior years.

One nutritional topic receiving considerable attention in veterinary medicine is omega-3 fatty acids, particularly two compounds called DHA and EPA. These essential components of a healthy diet have important roles in the body, from supporting normal brain function to helping regulate inflammatory processes.

But what exactly are DHA and EPA, why are they important for dogs/cats, and what makes them especially relevant as our companions grow older?

What Are DHA, EPA, and Omega 3 Fatty Acids?

DHA (docosahexaenoic acid) and EPA (eicosapentaenoic acid) are long-chain omega-3 polyunsaturated fatty acids. They are naturally found in oily fish, fish oil, and certain marine oils. Algal oils can also provide these fatty acids, making them an alternative for some formulations.

Although DHA and EPA belong to the same family, they have different roles in the body.

DHA is particularly important for the brain and nervous system. It is a structural component of cell membranes, including those found in the brain and retina. Adequate DHA is important for normal neurological development and brain function throughout life.

EPA is especially well studied for its involvement in inflammatory signaling. The body uses EPA to produce and regulate signaling molecules that help coordinate inflammatory responses. These processes are important because inflammation is a normal part of the body's defense and repair systems, but excessive or persistent inflammation can contribute to certain health problems.

Both fatty acids contribute to normal physiology, and they are often studied together because they can complement one another.

It is also worth remembering that not all omega-3 fatty acids are interchangeable. Plant sources such as flaxseed provide alpha-linolenic acid (ALA), which dogs can convert into EPA and DHA only to a limited extent, so DHA and EPA are generally more beneficial than ALA when the goal is to raise those long chain omega-3s in dogs, especially for an older or ill dog because direct EPA and DHA are more readily available.

In practical terms, the main essential fatty acids discussed here are DHA and EPA, while omega-6 fatty acids, including arachidonic acid, are also essential and commonly supplied by commercial dog foods.

Omega-9 fatty acids are not essential because dogs can synthesize them, and dietary fats also help absorb fat soluble vitamins.

Supporting Joint Health and Mobility

One of the most noticeable challenges of aging in dogs is a change in mobility. Some dogs develop osteoarthritis, a progressive joint condition involving changes to cartilage, bone, and other joint tissues. It can lead to stiffness, discomfort, and difficulty with everyday activities.

EPA and DHA are relevant because they participate in pathways that regulate inflammation. EPA, in particular, can influence the production of inflammatory signaling molecules, helping explain the anti inflammatory effects that have led to interest in dogs fish oil as part of nutritional management for joint conditions.

Research in dogs with osteoarthritis has found that fish oil good sources of EPA and DHA are studied because they can help reduce inflammation in arthritic joints, and appropriately dosed supplementation can improve certain clinical measures, including discomfort and mobility related outcomes (Fritsch et al., 2010).

A randomized, double-blind, placebo controlled clinical trial involving dogs with osteoarthritis found improvements in several clinical outcomes after supplementation with EPA and DHA over 84 days (Mehler et al., 2016).

Omega-3 supplementation is not a cure for arthritis, and results depend on the dose and the individual dog. With fish oil supplementation, dose decisions for arthritis should be made with veterinary guidance, so consult your vet for specific omega-3 recommendations. However, EPA and DHA should be considered as part of a broader joint health plan alongside maintaining a healthy body weight, appropriate exercise, and veterinary care.

For aging dogs, supporting mobility can make a meaningful difference to daily life. Being able to rise comfortably, enjoy walks, and participate in familiar activities contributes to overall wellbeing.

Supporting Brain Health and Cognitive Function

Aging affects the brain as well as the body. Some senior dogs experience changes in learning, memory, sleep patterns, social interaction, or their awareness of familiar surroundings.

In some cases, these changes may be associated with canine cognitive dysfunction, a condition involving progressive changes in cognitive function. DHA is an important structural component of brain cell membranes. It contributes to the normal structure and function of neurons, the cells responsible for transmitting information throughout the nervous system. EPA and DHA are also involved in biological processes associated with cellular signaling and inflammation, which researchers are investigating in relation to healthy brain aging.

Studies examining omega-3 supplementation and nutrient enriched diets in aging dogs have reported beneficial effects in certain cognitive tasks, including aspects of learning and executive function (Bauer, 2016). Some evidence in senior pets also suggests omega-3s may support brain function more broadly during aging.

This is an encouraging area of research, but it is important not to overstate the findings. Omega-3 supplementation has not been shown to prevent all age related cognitive decline, and it should not be presented as a treatment for canine cognitive dysfunction on its own. Instead, DHA and EPA can be discussed as nutrients that support normal physiological processes involved in brain health, help support cognitive function, and may also influence the immune system as potential components of a broader approach to healthy aging (Wu, 2024).

Helping Maintain Healthy Inflammatory Responses

Inflammation is not inherently bad. It is a necessary biological response that helps the body react to injury and other challenges. Problems can arise when inflammatory activity becomes persistent or poorly regulated. This is why there is continued interesr and investigation of the role of omega-3 fatty acids in a range of health conditions, including some inflammatory diseases, and why an appropriate balance of omega-3 and omega-6 fatty acids matters for healthy inflammatory responses and immune function.

EPA and DHA influence the production of signaling molecules called eicosanoids and other lipid mediators. The hormones produced from omega-3s generally help reduce inflammation, while some mediators derived from omega-6s can promote it in certain pathways. Some of these compounds participate in inflammatory responses, while others help coordinate the resolution of inflammation. In simple terms, these fatty acids help supply the body with materials used in the processes that regulate inflammation.

This is particularly relevant when discussing aging because older dogs may be more likely to experience conditions involving chronic inflammatory processes, including osteoarthritis.

However, aging does not automatically mean a dog has excessive inflammation or needs high dose omega-3 supplementation. The appropriate amount depends on the dog's diet, body weight, health status, and specific nutritional goals, and supplementation may be used to help restore a better omega-3-to-omega-6 balance when a diet is heavy in omega-6 and to support heart function. The minimum omega-3 amounts for health maintenance in clinically normal dogs are different from the higher doses sometimes used for diagnosed inflammatory conditions.

Supporting Skin, Coat, and Cellular Health

Although joint and brain health often receive the most attention in discussions of senior dogs, omega-3 fatty acids also have roles in other areas of physiology.

Fatty acids contribute to cell membranes throughout the body, and dietary fats help maintain the skin barrier and support normal skin function; inadequate essential fats can contribute to fatty acid deficiency that affects skin and coat quality. Many commercial dog foods provide abundant omega-6 fatty acids but relatively limited omega-3s.

EPA and DHA have been investigated in dogs with certain inflammatory skin conditions, although the evidence and response to supplementation vary by condition and may help with skin allergies in some cases to support skin and a dog's skin response.

A healthy coat and comfortable skin are influenced by many factors, including protein intake, other essential fatty acids, vitamins, minerals, allergies, and underlying disease. Omega-3 supplementation should therefore be considered one potential part of nutritional support rather than a universal solution for skin problems, and when EPA and DHA are used appropriately, that balance may also help maintain healthy skin, coat health, and coat quality.

Do Older Dogs Need More DHA and EPA?

There is no single omega-3 dose that is right for every senior dog. The right oil dosage depends on the product and on factors like size, diet, and health status.

Aging dogs do not automatically require more EPA and DHA simply because they are older. Their nutritional needs depend on the composition of their regular food, energy intake, body condition, and whether they have health conditions that may benefit from targeted nutritional support throughout a dog's life (Vendramini et al., 2025). Some commercial diets contain added EPA and DHA, while others provide relatively little. The amounts can vary substantially between products.

For this reason, it is helpful to look beyond the total amount of fish oil listed on a label. The more relevant figures are the actual amounts of EPA and DHA delivered per serving, which also helps answer how much fish oil may be appropriate.

A supplement containing 1,000 mg of fish oil does not necessarily provide 1,000 mg of EPA and DHA. Fish oil contains a mixture of fats, so the EPA and DHA concentrations should be checked separately.

For dogs with osteoarthritis or other diagnosed conditions, a veterinarian can help determine whether supplementation is appropriate and establish a suitable dose. Therapeutic targets may also differ for conditions such as kidney disease or inflammatory bowel disease. Higher doses are not automatically better, and the total intake from food and supplements must be considered (Vendramini et al., 2025).

How Can You Support Healthy Aging Through Nutrition?

DHA and EPA are only part of a comprehensive approach to keeping dogs healthy as they age.

A complete and balanced diet, maintaining an appropriate body weight, preserving muscle mass, regular physical activity suited to the individual dog, preventive veterinary care, and attention to changes in behavior all contribute to healthy aging.

If you are considering an omega-3 supplement, fish oil products and other fatty acid supplements may help when a pet's diet does not provide enough EPA and DHA. Look for a product that clearly identifies its EPA and DHA content, provides appropriate quality and safety information, and is suitable for your dog's individual needs. Avoid human supplements, and choose dog fish oil products made for dogs, ideally with veterinary guidance.

Omega fatty acids may also offer health benefits beyond skin, coat, and joints, including support for cardiovascular health, heart health in dogs with heart disease, chronic kidney disease management, and lower blood triglyceride levels in some dogs. It is also important to discuss supplementation with your veterinarian if your dog has a history of pancreatitis, problems with blood clotting, a condition affecting fat metabolism, or is taking medication that could interact with high-dose omega-3s. Some dogs may experience digestive upset, and adding oil can increase dietary calories.

What About Cats? DHA and EPA for Healthy Aging in Felines

DHA and EPA are also important for cats throughout their lives, including their senior years. DHA supports normal brain and retinal function, while EPA participates in pathways that help regulate inflammatory responses. As cats age, these omega-3 fatty acids may be particularly relevant to maintaining joint health and supporting overall well-being. Research in cats suggests that omega-3 fatty acids may be useful as part of nutritional management for certain conditions, including osteoarthritis, although the strength of evidence varies by condition. Like their canine counterparts, cats have limited ability to convert plant derived omega-3 fatty acids into EPA and DHA. This makes direct dietary sources particularly relevant. As with dogs, the appropriate amount depends on the cat's diet, health status, and individual needs (Vendramini et al., 2025). A veterinarian can help determine whether supplementation is appropriate and ensure that it complements a complete and balanced feline diet.

Keep in mind

DHA and EPA are important omega-3 fatty acids that support normal cellular function and participate in processes relevant to brain health and inflammatory regulation.

Research in dogs provides particularly useful evidence for EPA and DHA in the nutritional management of osteoarthritis. Studies of aging dogs also suggest potential benefits for certain aspects of cognitive function, although more research is needed to establish the best approaches for individual dogs (Burron et al., 2024).

As your dog grows older, thoughtful nutrition can help support their overall wellbeing. Understanding the role of DHA and EPA is one way to make informed decisions about their diet and discuss appropriate nutritional strategies with your veterinarian.

Healthy aging is not about stopping the clock. It is about helping your dog stay comfortable, engaged, and able to enjoy the activities that make life special for as long as possible.

References

Bauer, J. E. (2016). The essential nature of dietary omega-3 fatty acids in dogs. Journal of the American Veterinary Medical Association, 249(11), 1267-1272.

Burron, S., Richards, T., Krebs, G., Trevizan, L., Rankovic, A., Hartwig, S., ... & Shoveller, A. K. (2024). The balance of n-6 and n-3 fatty acids in canine, feline, and equine nutrition: exploring sources and the significance of alpha-linolenic acid. Journal of animal science, 102, skae143.

Fritsch, D., Allen, T. A., Dodd, C. E., Jewell, D. E., Sixby, K. A., Leventhal, P. S., & Hahn, K. A. (2010). Dose-titration effects of fish oil in osteoarthritic dogs. Journal of veterinary internal medicine, 24(5), 1020-1026.

Mehler, S. J., May, L. R., King, C., Harris, W. S., & Shah, Z. (2016). A prospective, randomized, double blind, placebo-controlled evaluation of the effects of eicosapentaenoic acid and docosahexaenoic acid on the clinical signs and erythrocyte membrane polyunsaturated fatty acid concentrations in dogs with osteoarthritis. Prostaglandins, Leukotrienes and Essential Fatty Acids, 109, 1-7.

Vendramini, T. H. A., Marchi, P. H., Olivindo, R. F. G., Pedrinelli, V., Amaral, A. R., de Miranda, M. S., ... & Brunetto, M. A. (2025). Exploring the efficacy and optimal dosages of omega-3 supplementation for companion animals. Nutrition Research Reviews, 38(2), 859-874.

Wu, G. (2024). Roles of nutrients in the brain development, cognitive function, and mood of dogs and cats. In Nutrition and Metabolism of Dogs and Cats (pp. 177-202). Cham: Springer Nature Switzerland.