If you are researching supplements for your senior dog and wondering, “Is MCT oil the same as fish oil for dogs?”, you’ve come to the right place. Integrative veterinarian Dr. Julie Buzby discusses how two products she loves for senior dogs—MCT oil and fish oil—are different from each other and explains how they work, which dogs might benefit from them, and what to look for in an MCT oil or fish oil product.
With the plethora of dietary supplements for senior dogs on the market, it can be easy to get confused about which supplement does what and which ones you can use together. For example, when I mention MCT oil, dog parents frequently say, “My dog is already on a fish oil supplement. Isn’t that the same as MCT oil?”
It is understandable to equate omega-3 fatty acids (as found in fish oil) and medium chain triglycerides (MCTs) since both are dietary fats. However, they do not work the same way in the body and, therefore, don’t have the same benefits. To make a silly analogy, MCT oil is a spoon, fish oil is a fork—they’re not both sporks.
Is MCT oil the same as fish oil for dogs?
While both may be beneficial for senior dogs, MCT oil and fish oil are not the same.
MCT oil products for dogs provide a source of the medium chain triglycerides (MCTs) C8 and C10. These medium length fats provide a rapid fuel source for the brain to support dogs with cognitive dysfunction. Plus, they may help decrease seizure frequency or severity in dogs with epilepsy. And MCTs have heart health and digestive system benefits, too.
On the other hand, fish oil is a source of omega-3 fatty acids, which are long chain fatty acids. Omega-3s become part of the membranes that surround every cell in the body to help maintain healthy cell structure and function. And they help produce compounds that regulate inflammation, supporting the long-term health of tissues throughout the body, including the brain, joints, skin, heart, kidneys, eyes, and immune system.
Since they are different, in many cases, you can combine fish oil and MCT oil to cash in on the benefits of both. Let’s take a closer look at both MCT oil and fish oil as supplements for senior dogs.
What is MCT oil for dogs?
Medium-chain triglycerides (MCTs) are water-soluble, saturated fats that are most commonly found naturally in tropical oils like coconut and palm kernel oil. Interestingly, dairy products like whole milk, Greek yogurt, butter, and cheese also naturally contain low levels of MCTs. For this article, however, we’ll be focusing on coconut oil derivatives.
The end purification product of these tropical oils includes medium-chain fatty acids with carbon chain lengths varying from 6 to 12 carbon atoms (C6–C12).
- Caproic acid (C6): Poorly palatable and thus not usually included in human or dog MCT oil supplements.
- Caprylic acid (C8): Rapidly converted into ketones, an alternative source of energy for the brain.
- Capric acid (C10): Has anti-inflammatory effects on neurons and may help improve energy production within the cells.
- Lauric acid (C12): May increase the risk of pancreatitis in more sensitive or pancreatitis-predisposed dogs. Thus, it may not be ideal to include in dog-specific MCT oil supplements.
Out of this list, the two MCTs of value to dogs are C8 and C10. Thus, they are the ones that typically show up in MCT oil supplements for dogs.
What are the benefits of MCT oil for dogs?
MCT oil for dogs supports many systems in the body. Some of its claims to fame include:
Supporting brain health and cognitive function
Unlike most dietary fats, MCTs take a metabolic shortcut in the digestive process. This allows the liver to rapidly convert them into ketone bodies (β-hydroxybutyrate), an easy-to-use and readily available alternative fuel source for the brain. Normally, the brain runs on glucose. But senior dogs and those with some other medical conditions may not be able to use glucose as efficiently. This is where ketones from MCT oil can step in to keep the brain fueled up.
Research has also shown that MCTs support mitochondrial function (the tiny “power plants” inside cells). This helps maintain learning ability, memory, and overall cognitive function in senior dogs. In fact, in a study of older Beagles supplemented with MCTs, those who received the MCTs performed better on a variety of cognitive tests than those who didn’t.
Decreasing seizure frequency and severity
Recent studies indicate some dogs with idiopathic epilepsy may experience less frequent or less severe seizures when MCT oil is added to their diet in combination with anti-seizure medication. That said, it’s important to understand that the goal of MCT oil is to complement, not replace, your dog’s prescribed epilepsy treatment.
Supporting dogs with mitral valve disease
A Journal of the American Veterinary Medical Association (JAVMA) review article that discussed key nutrients for managing mitral valve disease (MVD) in dogs and heart failure mentioned that MCTs are beneficial because they may provide an alternative energy source for the heart, much like they do for the brain. And it noted that MCTs may also reduce the production of harmful free radicals. (As you will discover, fish oil also hit this list of important nutrients for MVD.)
Additionally, a small study in BCM Veterinary Research showed a cardiac protection blend of nutrients that included MCTs, fish oil, and antioxidants might slow the progression of early MVD and decrease left atrial enlargement (the heart chamber that gets bigger with MVD). However, more research is needed.
Improving digestive health
MCTs are easy to absorb and require very little digestion. This may make them helpful for dogs with gastrointestinal disorders such as inflammatory bowel disease (IBD) in dogs, protein losing enteropathy (PLE in dogs) and intestinal lymphangiectasia.
Aiding in recovery from fasting or illness
MCT oil can also help cells produce energy more efficiently. This may be especially beneficial for dogs experiencing insulin resistance, prolonged fasting, recovery from critical illness, or other situations that involve impaired glucose availability or use.
Managing body weight
Since MCTs are quickly converted into ketones, they’re generally less likely than long-chain fats to be stored as body fat. They do, however, still add calories to the diet.
Researchers also noted that MCTs may help humans feel fuller after eating (satiety). This could potentially make them a useful part of an overall weight-management plan for dogs as well.
What is fish oil for dogs?
Fish oil contains the long-chain omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Although they are often grouped together as “omega-3s,” EPA and DHA each play unique roles in the body.
- EPA: Best known for helping regulate inflammation, support joint comfort, maintain healthy blood triglyceride levels, and promote cardiovascular health.
- DHA: A major structural component of the phospholipid layer of cell membranes throughout the body. This includes the brain, retina, and sperm cells.
Fish oil is typically purified from fatty, cold-water fish like salmon, mackerel, sardines, and tuna after the fish are cooked and the oil is pressed from the tissues. EPA is found almost exclusively in marine fish. But DHA occurs naturally in both fish and algal (seaweed) sources, making algae an alternative source of this important omega-3 fatty acid. Throughout this article, however, we will only be focusing on the fish-origin sources of DHA.
How can fish oil benefit my senior dog?
Because they become part of cell membranes and help regulate the body’s inflammatory response, omega-3 fatty acids for dogs may provide many benefits for dogs (and cats), including:
Improving joint health and decreasing joint inflammation
EPA and DHA help reduce inflammation associated with arthritis in dogs and other joint conditions. This makes them a valuable addition to a comprehensive mobility plan for many dogs, especially senior dogs.
Promoting healthy skin and coat and aiding in wound healing
Omega-3 fatty acids help nourish the skin and coat. They also promote wound healing by maintaining healthy skin cell production and supporting the body’s natural repair processes.
Supporting brain development and cognitive function
DHA is an essential structural component of brain cells and naturally concentrates in the brain and retina. It supports healthy brain development, which is why it is a common ingredient in puppy diets and human infant formulas. And it continues to support cognitive function throughout a dog’s adult and senior years.
Regulating inflammation in some heart diseases
The JAVMA article mentioned earlier noted that omega-3 fatty acids help reduce inflammation associated with heart failure and support overall heart function. Studies have also shown EPA might help maintain healthy blood triglyceride levels and normal blood pressure.
Providing immune system support
EPA and DHA help the immune system respond appropriately to injury and illness. And they also assist in resolving chronic inflammation that can damage tissues over time. Plus, omega-3s help reduce oxidative stress, which is associated with aging and the onset of many chronic diseases.
Helping manage allergies and cancer
Vets commonly recommend fish oil as part of the management plan for seasonal allergies in dogs. And research indicates it may play a role in the treatment of certain cancers, including lymphoma in dogs.
Can my dog take both MCT oil and fish oil?
Because MCT oil and fish oil work in different ways and have different benefits, vets may use them both as part of a comprehensive wellness plan for senior dogs. Together, they provide broader support for healthy aging than either supplement alone.
However, keep the following guidelines in mind:
- Don’t forget to account for the calories: Although both supplements offer health benefits, they also provide additional calories. It’s important not to forget to factor those calories into your dog’s daily dietary allowance. Feeding too much of either supplement may upset your dog’s stomach and contribute to unwanted weight gain with long-term use.
- Talk to your vet first, if your dog has certain health conditions: If your dog has a history of pancreatitis in dogs, chronic digestive problems, or other conditions that require careful fat management, he or she should only receive MCT oil or fish oil under the guidance of your vet. Additionally, if your dog has cancer, speak with your vet before adding fish oil or any new supplement to your dog’s diet. This helps ensure that the new addition won’t interfere with his or her treatment.
- Start slow and work up: Introduce MCT oil and fish oil slowly (ideally over a couple of weeks). For dogs with a sensitive stomach, starting with a small amount and increasing the amount slowly over several days is especially important for helping minimize the risk of gastrointestinal upset.
- For dogs on a prescription diet, talk to your vet before adding supplements: If your dog is currently eating a therapeutic or prescription diet, consult your vet before adding an MCT oil or fish oil supplement. Some commercial diets already include therapeutic levels of these nutrients. Thus, additional supplements could result in your dog receiving more of these nutrients than they need.
How do you give MCT oil or fish oil to your dog?
Once you’ve decided to try fish oils, MCT oils, or both, the next order of business is to select a specific supplement or source of the nutrients.
Forms of MCT oil
MCT oil most commonly comes in a liquid form, like Dr. Buzby’s Brain Boost™ organic MCT oil for dogs that you can pour directly over your dog’s food. Powdered supplements and certain commercial or prescription diets designed to support cognitive health, such as Purina Pro Plan® Bright Mind® and Purina Pro Plan® Veterinary Diets NeuroCare® may also contain MCT oil.
When choosing an MCT oil supplement, you’ll notice that products vary based on their fatty acid composition:
C8 (caprylic acid) MCT oil contains only caprylic acid. C8 is the most ketogenic medium-chain fatty acid. This means the body can convert it into ketones more efficiently than the other MCTs. Thus, vets and dog parents may prefer caprylic acid when the goal is to support brain health, cognitive function, or ketogenic therapy.
C8/C10 MCT oil combines caprylic acid (C8) and capric acid (C10). This is the formulation most canine studies use to investigate the potential benefits for dogs with cognitive dysfunction and/or idiopathic epilepsy. While C10 produces ketones less efficiently than C8, it has its own unique metabolic benefits and is commonly included in veterinary MCT supplements.
Some MCT oil supplements for dogs may also contain lauric acid (C12). However, because it may increase the risk of pancreatitis in pancreatitis-prone dogs or lead to GI upset, it is generally safer to select products that are free from lauric acid.
Can you use regular coconut oil instead of MCT oil?
It’s easy to assume that you can use coconut oil and MCT oil interchangeably since MCT oil is derived from coconut oil. But the two are not the same.
Raw coconut oil contains approximately 66% medium-chain triglycerides. Of this fraction, lauric acid (C12) accounts for roughly 46 to 54%. The remaining MCT fraction is composed of much smaller amounts of caprylic acid (C8) and capric acid (C10) at only 5 to 10% each. And caproic acid (C6) makes up less than 1%.
Since C8 and C10 are the MCTs that are beneficial for dogs, and C12 may be linked with pancreatitis, these percentages matter. Coconut oil only provides a small fraction of C8 and C10 compared to an MCT oil product composed only of C8 and C10. Plus, the C12 in coconut oil may be problematic, especially for pancreatitis-prone dogs or those with a history of sensitive digestion.
So long story short, unrefined coconut oil is not a good substitute for MCT oil.
Forms of dog fish oil supplements
Fish oil omega-3 supplements are available in many forms, including liquids, softgels, and capsules. Liquid formulations are often the easiest option for dogs because you can simply pour or pump the oil onto the food. And capsules may work well for dogs who readily take pills or treats.
(NOTE: Commercial dog foods may also contain omega-3 fatty acids, but not necessarily in high enough amounts to provide therapeutic benefits. Thus, your vet may recommend adding a fish oil supplement to your dog’s food.)
When choosing a fish oil supplement, you’ll likely see several different formulations:
- Natural triglyceride (TG) fish oil is the form that occurs naturally in fish. It’s generally well absorbed and may retain naturally occurring nutrients. However, this form does carry an inherent risk of contaminants depending on how well it’s purified.
- Ethyl ester (EE) fish oil is a purified, concentrated form that often contains higher amounts of EPA and DHA. High-quality products are distilled to remove contaminants such as heavy metals and polychlorinated biphenyls (PCBs).
- Re-esterified triglyceride (rTG) fish oil is produced by converting concentrated ethyl ester oil back into a triglyceride form. It maximizes high EPA and DHA concentrations with excellent absorption. And it is often considered a premium formulation.
Supplement quality matters
No matter which form of fish oil or MCT oil you choose, look for reputable manufacturers that use independent, third-party testing. Those test results help verify the amount of EPA, DHA, and MCTs in the products. And, in the case of fish oil, it helps confirm that the product has been screened for contaminants.
If you’re unsure which brands are most reputable, ask your vet for his or her recommendation. He or she likely has a preferred brand and may actually carry the supplement in their clinic inventory.
What are the possible side effects of MCT oil or fish oil?
Dogs generally tolerate both MCT and fish oil well when introduced gradually and given at the recommended dose. However, as with any supplement, some dogs may experience side effects, particularly if they recieve too much.
Side effects of MCT oil supplements
Most side effects of MCT oil are digestive in nature. And they are most likely to occur when you introduce the supplement too quickly. Side effects may include:
- Soft stools or diarrhea
- Excessive gas
- Bloating or abdominal discomfort
- Vomiting
Side effects of fish oil supplements
The most common side effects of fish oil also involve the digestive tract and are usually mild. These may include:
- Soft stools or diarrhea
- Nausea and vomiting
- Increased gas or bloating
- Fishy-smelling breath or burps
- A greasy coat or oily skin around the mouth
Less commonly, very high doses of fish oil may interfere with normal blood clotting. This increases the risk of bruising or bleeding. If your dog is going to have surgery, your veterinarian may recommend stopping fish oil 5 to 7 days beforehand to help minimize the risk of excessive bleeding.
Omega-3 fatty acids can also increase the body’s need for vitamin E. Thus, many veterinary fish oil supplements include vitamin E or recommend also using a Vitamin E supplement if giving fish oils long term.
Are there dogs who should not take MCT oil or fish oil?
Although MCT oil and fish oil are safe for many dogs, they may not be appropriate for every dog.
Talk with your veterinarian before starting MCT oil if your dog has liver disease in dogs, a history of diabetic ketoacidosis (DKA in dogs), GI disorders requiring a therapeutic diet, or a history of pancreatitis or other pancreatic disorders.
Also, Cavalier King Charles Spaniels should not have MCT oil unless genetic testing reveals they are either free of or only a carrier of medium-chain acyl-CoA dehydrogenase deficiency (MCADD). This is the case because dogs with MCADD can’t break down medium chain fats like MCT oil appropriately.
Likewise, consult your veterinarian before using fish oil if your dog has a bleeding or clotting disorder, is taking anticoagulant medications, or has a history of pancreatitis.
As with any new supplement, it is generally best to start with a small amount and increase gradually according to your vet’s recommendations or the product label. If your dog develops persistent vomiting, diarrhea, loss of appetite, unusual bruising, or any other concerning signs, stop the supplement and contact your veterinarian.
MCT oil vs fish oil? Your vet’s guidance
When used appropriately, MCT oil and fish oil are generally safe, well-tolerated natural supplements for dogs that support healthy aging in our beloved canine companions in different but complementary ways.
MCT oil provides an alternative source of energy, especially for the brain, while fish oil supplies the omega-3 fatty acids your dog needs to support healthy cells and help regulate inflammation. Your veterinarian can work with you to determine whether one or both are appropriate to support your dog’s health and overall quality of life.
Is your dog taking an MCT oil or fish oil supplement?
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