The Skinny on Oils
From fish oil to coconut oil, discover the health benefits of these supplements.
Article by Mary Straus, published in Dog Fancy's Natural Dog Magazine, Winter 2013.
If your dog has a dull coat, dry skin or other skin or coat problems, it’s likely that someone has suggested adding oils to his diet. But what kind of oils should you give him?
Fish oil, flaxseed oil, coconut oil, olive oil, and various omega blends are popular choices. Some of these oils provide benefits such as contributing to a healthy coat and skin, reducing inflammation, and supporting the immune system. Others offer little benefit, and might even increase inflammation.
Let’s take a look at some of the different supplemental oils and the benefits they offer.
One of the more popular supplemental oils in recent years, coconut oil proponents claim it can improve digestion, reduce inflammation, lower the risk of cancer and heart disease, prevent and treat infection, reduce allergic reactions, contribute to normal thyroid function, and much more. Owners who give their dogs coconut oil report shiny coats, healthy skin and less odor.
Unlike most other oils, coconut oil is comprised of saturated fats. These are different from the omega fatty acids, which are polyunsaturated and monounsaturated fats found in fish and vegetable oils. Saturated fats are solid at room temperature, but coconut oil becomes liquid at 76 degrees Fahrenheit. Good quality coconut oil is colorless when liquid and white when solid, and does not smell or taste rancid or smoky.
Some of the fat in coconut oil is in the form of medium-chain triglycerides, or MCTs, which are responsible for the majority of its benefits. Dogs with fat intolerance might more easily digest MCTs than other fats. Dogs who must be fed very low-fat diets because of problems with fat digestion might benefit from the addition of small amounts of coconut or MCT oil, which can help them feel satisfied and avoid deficiencies of fat-soluble vitamins.
What to look for: There are two types of coconut oil. Refined coconut oil, which may be labeled RBD for “refined, bleached, and deodorized,” has been treated with chemicals, and most of the nutritional value has been removed. Instead, look for “virgin” unrefined coconut oil, preferably in glass rather than plastic containers. Never feed hydrogenated coconut oil.
How to use: If you decide to add coconut oil to your dog’s diet, start slowly with small amounts, increasing them gradually every few days. If you see problems such as diarrhea, lethargy or discomfort, reduce the amount that you give. The maximum recommended dose is 1 teaspoon per 10 pounds of body weight daily, divided into multiple servings, but that’s a lot of fat; less may be better.
You can feed coconut oil directly, mix it in food, or use it in cooking. Apply it topically to disinfect and promote healing of sores, bites, stings, cracked paw pads and wounds, and use it as a carrier oil for aromatherapy. You can also feed fresh or dried coconut.
Another beneficial oil, fish oil provides eicosapentaenoic acid, or EPA, and docosahexaenoic acid, or DHA, which are omega-3 essential fatty acids that help regulate the immune system, reduce inflammation, support the brain and nervous system, and contribute to skin, coat, heart, and kidney health. EPA and DHA are also found in krill oil, cod liver oil, and fatty fish, and DHA is found in some types of algae.
Most dogs can benefit from fish oil supplements, even if they are fed a fish-based commercial food, because omega-3 fatty acids become rancid when exposed to light, heat, and air.
What to look for: Most fish oil gel capsules contain 200 to 300 milligrams combined EPA and DHA. Check the label to confirm how many capsules provide the amounts listed. Fish oil also comes in liquid form, which should be stored in dark bottles in the refrigerator and used within a couple of months after opening to prevent rancidity.
How to use: Healthy dogs do well with 100 to 150 mg combined EPA and DPA per 10 pounds of body weight daily. Increase the amount to 300 mg combined EPA and DPA per 10 pounds for dogs with allergies, arthritis, kidney disease, heart disease, cancer, or other inflammatory or immune-mediated conditions. The omega-3 fatty acids in krill oil and whole fish are better absorbed, so smaller amounts may provide comparable benefits.
Fatty fish, such as jack mackerel, pink salmon, sardines and regular – not light – tuna, provide on average about 300 milligrams combined EPA and DHA per 1 ounce of fish. Feed fish that's canned in water, not oil. Smaller fish contain less mercury than large fish, such as tuna.
Cod liver oil that is not molecularly distilled also contains vitamins A and D, fat-soluble vitamins that are stored in the body and should not be oversupplemented. Limit amounts you serve to your dog. If you want to offer higher doses of EPA and DHA, add plain fish oil.
Most plant oils, such as corn oil, vegetable oil or soybean oil, walnut oil, and canola oil, are high in linoleic acid, a polyunsaturated omega-6 fatty acid. Linoleic acid, which is also found in poultry fat, is considered an essential part of the diet, but it's generally plentiful, and too much promotes inflammation. It's almost never a good idea to supplement with oils that are predominately linoleic acid.
Some plant oils, including borage seed oil, evening primrose oil, black currant seed oil and, to a lesser extent, hempseed oil, contain a better form of omega-6 called gamma-linolenic acid, or GLA, which is anti-inflammatory.
Flaxseed oil is different from other plant oils. It contains primarily alpha-linolenic acid, or ALA, an omega-3 fatty acid. Dogs cannot directly utilize ALA, however. It must first be converted to EPA and DHA in the body, a process that does not work very well in dogs. At best, dogs convert 15 percent of ALA, but this amount may be much lower or nonexistent for many dogs. For this reason, flaxseed oil and ground flaxseed are not good substitutes for fish oil supplements.
Olive oil provides primarily oleic acid, a monounsaturated omega-9 fatty acid that is not considered essential, but might provide benefits, including reducing the risk of certain types of cancer. Olive oil might also help reduce inflammation, although it’s not clear why. Some plant oils, such as safflower and sunflower oil, are available in high-oleic versions.
The benefits of olive oil for dogs are not well understood. In humans, olive oil can improve cholesterol levels, reducing the risk of heart disease and hardening of the arteries, but these benefits likely do not apply to dogs, as they are not affected by cholesterol in the same way that people are.
If you choose to supplement with olive oil, keep amounts small and do not use it to replace other beneficial oils, although it could be used as part of a rotation.
There are a number of oil, fatty acid and omega blends made for both humans and dogs. Many contain primarily omega-6 fatty acids, which should not usually be supplemented. If you use an oil blend, look for one that is high in beneficial oils, not plant oils that are mostly linoleic acid.
Watch the Fat
It’s important to understand that when you add oil to your dog’s diet, you’re adding fat and calories. One teaspoon of oil contains 4.5 grams of fat and 40 calories. That isn’t too much for a large dog, but it’s a huge amount for a toy breed. Too much fat can lead to digestive upset, obesity, nutritional inadequacy if feeding amount is reduced to prevent weight gain, and even pancreatitis in susceptible dogs.
Oil Supplement Tips
Storage and safety: All oil supplements should be fresh. Oils that are not processed or stored properly can become oxidized, or rancid, a source of free radicals that are damaging to the body. Most liquid oils should be stored in dark bottles to protect them from light, and some, such as fish oil, should be refrigerated as well. Never feed any oil that smells “off.”
Where to buy: You can use oil supplements made for either humans or pets. Good quality supplements can be found at health food stores and online from sites specializing in holistic supplements, such as Only Natural Pet and HolisticPetInfo. You can also find oil supplements at grocery stores, drug stores, pet supply stores and big-box retailers such as Target and Costco.
Keep it natural: Avoid products that include food coloring, chemical preservatives and artificial additives such as polysorbate 80 and propylene glycol.
You can contact me if you have any comments, but I regret to say that I can no longer respond to questions about individual dogs. See my Contact page for more information. My name is Mary Straus and you can email me at either or