5 Disease-Fighting Foods for Your Dog

By Paula Fitzsimmons

Flaxseed, blueberries, and oatmeal are some of the foods experts recommend we eat to stave off illness and maintain peak health and wellness. You naturally may have wondered…Does this apply to dogs, too? Are there certain foods you can feed your dog to keep disease at bay?

There are no magic formulas, as in feed your dog an apple a day to keep the veterinarian away. “It’s the overall diet that keeps us healthy and this is most likely true in dogs as well, says Dr. Donna Raditic, a board-certified veterinary nutritionist with Nutrition and Integrative Medicine Consultants based in Athens, Georgia. “For example, eating one cup of blueberries and a half cup of oatmeal for breakfast every morning may have a limited effect in a person who then eats burgers, French fries, and soda pop.”

This is not to say you should avoid giving your dog specific foods known for their high nutritional content. “For instance, I happen to believe (without proof yet) that the biochemical complexity of a fresh diet is important,” says Dr. Susan Wynn, a board-certified veterinary nutritionist with BluePearl Veterinary Partners in Sandy Springs, Georgia.

There just isn’t enough evidence-based research on functional foods (foods with health benefits) for dogs at this point. That said, the following foods may be worthy of your attention as part of an overall diet. Remember to go over any changes in your dog’s diet with your vet, especially when it comes to supplements.

Fish Oil

Foods rich in omega-3 polyunsaturated fatty acids have been studied extensively for their role in controlling inflammation in a variety of species, says Dr. Jonathan Stockman, a board-certified veterinary nutritionist at the James L. Voss Veterinary Teaching Hospital at Colorado State University in Fort Collins. “These fatty acids have been shown to help in the management of kidney disease, joint disease, skin inflammation, and more.”

Many pet foods contain omega-3 fatty acids, he says, but not all of them. “In addition, the amount added to [over-the-counter] products may not be sufficient to provide the desired beneficial effects.”  

The type of omega-3 fatty acids you feed your dog is also important. “Omega-3 fatty acids from plant sources such as flax (a source of alpha-Linolenic acid) are inefficiently metabolized to eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in dogs and cats,” Stockman says. “EPA and DHA are the beneficial omega-3 fatty acids in terms of impact on the inflammatory process.” This is why most veterinarians recommend omega-3 supplements derived from certain types of fish oil. Specially-formulated diets with appropriate amounts of EPA and DHA are also available by checking with your vet.

Supplements are an option, but there are some things you should be aware of before buying a bottle. The manufacturer should have adequate quality control practices in place to ensure their products are free from toxins and metal contamination, Stockman says. “Contacting the manufacturer to receive information on quality control and product testing is recommended when choosing a new omega-3 or fish oil supplement.”

There are dozens of omega-3 supplements on the market, many of which Stockman says are formulated for humans. But there are solid reasons why you should opt for supplements made for pets instead. “Many human products are supplemented with high levels of vitamin A or D, and over-supplementation may be risky.” He adds that fish oil is a source of extra fat calories, and in very high doses may have adverse effects on your dog. For these reasons, he suggests consulting with a vet or board-certified veterinary nutritionist first.

If you’re not a fan of supplements or your dog food doesn’t contain omega-3s, consider steaming, grilling, or baking a piece of fish for your canine companion. Be mindful of the type of fish you choose, as some varieties are higher in mercury than others. Salmon is a good option since it is typically high in omega-3s but low in mercury.

Vegetables

Leafy green and yellow-orange vegetables, such as carrots, may decrease the risk of bladder cancer in certain dogs, a 2005 study of Scottish Terriers suggested.

The goal of the study was to determine how vegetables (and supplements) might impact the development of transitional cell carcinoma (TCC) in Scottish Terriers. The scientists compared their findings of 92 Scottie dogs with confirmed cases of TCC, to those of 83 Scottie dogs with other conditions like parasitic infections and skin disease. Dogs who were fed veggies at least three times per week (carrots were the most often used) saw a reduction in the risk of developing TCC.  

The scientists suspect bioflavanoids, dietary fiber, plant sterols, and other anti-carcinogenic substances (known as phyto-nutrients) present in these vegetables may inhibit or slow down the progression of cancer. 

Yellow-orange vegetables used in the study (aside from carrots) included pumpkin, squash, and sweet potato. Leafy green vegetables included lettuce, salad greens, spinach, collard greens, and parsley. Raditic also recommends giving dogs swiss chard, turnip greens, beet greens, kale, and dandelion greens.

Mushrooms

Mushrooms contain polysaccharopeptides (PSP), which researchers believe have tumor-fighting properties. “There is some evidence that they can improve immune responses,” Wynn says.
 

There’s a lot of data on how eating mushrooms can impact humans, and researchers at the University of Pennsylvania School of Veterinary Medicine in Philadelphia ran a trial on dogs with hemangiosarcoma, an aggressive cancer affecting the spleen, Raditic says.

“I have used [a formulation of PSP] for many patients with different types of cancer based on human data,” she says.

The study involved researchers asking pet parents to feed their dogs capsules containing extracts from the Yunzhi mushroom every day. Each month, they brought their dogs to the university’s Ryan Veterinary Hospital for followup visits. They found that the compound was effective at fighting the tumors, without needing any accompanying treatments.

If you do want to offer your canine companion mushrooms, it’s important to keep in mind that some types of mushrooms are poisonous for dogs. Always talk to your veterinarian before adding mushrooms to your dog’s diet.

Fiber

In some cases, veterinarians may recommend feeding oatmeal or lentils as part of a high-fiber diet, Wynn says. Flax, psyllium, or chia seeds can also be used to supplement your dog’s diet, she adds.

Fiber can help your dog feel full, and ultimately aid with weight loss, Stockman says. Keeping your dog lean is important. Obesity can shorten your dog’s lifespan, and is linked with an assortment of diseases, including joint, liver, and respiratory disease.

Fiber is also essential for maintaining gastrointestinal health, as it helps support the gut microflora, he adds. A healthy gut is linked with strengthened immunity, a factor in warding off disease.

Pet foods are often supplemented with fiber sources, such as beet pulp, psyllium, guar gum, and grain hulls, Stockman says. You can also try adding a small spoonful of plain oatmeal to your dog’s regular food.

There are some precautions to take when choosing foods and products with fiber. Stockman says they may have negative effects in some patients, “as excess fiber may reduce nutrient bioavailability, and may even cause discomfort or flatulence.” He also cautions against feeding products that contain additives like xylitol (a sugar substitute), which is toxic to dogs.

Fruits

Raditic says veterinary nutritionists will often recommend that their clients feed fruits to their dogs as part of a sound nutritional plan. “We make these recommendations because these fresh fruits and vegetables may provide trace nutrients or compounds that we have yet to discover, or that are not abundant in commercial pet food.”

She prefers giving fruits and vegetables over commercial pet treats. “If an owner is giving blueberries (or carrots, etc.), to their dog, we then know exactly what it is and where it came from.” It can be difficult to identify the sources of all the ingredients—some of which have questionable nutritional value—in commercial pet treats.

The phyto-nutrients contained in blueberries and other fruits may help prevent cancer, Wynn says. “This is one reason I do recommend that people train their puppies to have a taste for vegetables in particular, and also fruits.” (No onions, garlic, grapes, or raisins, of course, which are toxic for dogs.) She also suggests fruits because they are low-calorie treats, “and we have a canine obesity problem.”

A general serving size for dogs, according to Raditic, consists of five blueberries. Other fruits she recommends include a whole medium-sized strawberry, or an inch of banana (this is an approximate serving for a 20-pound dog).

There is no one food currently known to guarantee that your dog will remain disease-free. Until research catches up, vets stress the importance of a balanced diet. Ensuring your dog has adequate amounts of nutrients provided by foods like fish, carrots, mushrooms, oatmeal, and blueberries can go a long way to ensuring she remains your healthy companion for a long time.