How Much Omega-3 Fish Oil Is Safe for Dogs?

By Martha Adams

Grilled fresh salmon, broiled bluefish, sardines on toast, even anchovies on pizza: If these items are on your menu regularly -- say, twice a week -- you may be getting all the omega-3s you need. Next question: Is your dog getting all he needs?

What Is an Omega-3?

Omega-3s are certain polyunsaturated fats that neither your body nor your dog’s can manufacture, so you both need to get them from an outside source. This can be what’s on your plate or in his bowl, or it can come in concentrated form as a dietary supplement. Omega-3s come from a few plants, such as flaxseed, walnuts and canola oil, but are more abundant, more accessible and let’s face it, more appetizing, when they come from the sea. Oily fish is a prime source of omega-3s. So is krill, a tiny shrimplike creature that lives in the ocean and is the staple diet of gigantic whales and baby fish. Some secondary sources are cod liver oil and whale blubber, but the less said about these, the better; your dog probably won’t like them any better than you would.

What Can It Do for My Dog?

Omega-3s are a sort of general panacea, providing what’s missing and fostering overall good health. They can improve a dog’s coat. They can help an elderly dog who has arthritis because of their anti-inflammatory effect. They can help an aging dog think better. If a dog has allergies, they can help calm his overactive immune system; if his immune system is weak, they can strengthen it. They can even help him lose excess weight. Remember, though, that they are powerful substances and, like salt in the soup, too much can be as bad as too little.

How Do I Give It to Him?

Some dogs relish canned fish – salmon, tuna or mackerel -- added to their dinner or canola oil dribbled over their kibble. If yours doesn’t, you may have to resort to capsules of fish oil or krill oil. Krill oil is more concentrated and therefore comes in smaller packages, and it won’t give your best buddy “fish breath.” Supplements made specifically for dogs usually tell you on the label how much to give, expressed as milligrams per pound of the dog’s body weight. Human supplements are also appropriate for dogs, but you’ll need your vet to help calculate your dog’s dose according to the concentration. Consult your veterinarian before giving your dog any supplements. How you get the stuff into the dog is between you and him.

What's the Downside?

Under the Law of Unintended Consequences, doing good things can actually cause bad things to happen. An overdose of omega-3s can harm your dog by interfering with the ability of his blood to clot -- not good after surgery or an injury, so if he’s already on supplementation, be sure his vet knows about it. It may be necessary to lower his intake, or even stop it temporarily. An excess can slow healing by reducing the natural inflammatory reaction that rushes white blood cells to an injury site. This can increase the possibility of infection or slow the immune system’s reaction to a long-term challenge such as cancer.