Is Your Dog's Grain-Free Diet the Best Choice?

We want our dogs to love their food as much as we love ours. Chendongshan/Shutterstock

Grain-free, organic and non-GMO; local sourcing and fancy proteins — these are popular food trends for humans, so it's no surprise that we've passed them along to our pets.

Researchers have made incredible strides in pet nutrition and, as a result, our pets are living longer, healthier lives. There are dozens more choices in the pet food aisle for consumers who can make selections based on their pet's size, breed, activity level or health condition.

But sometimes, we go overboard.

According to a pet owner survey, American spend an average of about $140 each month on their dogs and $93 on their cats. People ages 18 to 24 spend even more than that. They want the best for their pets and that often means high-end food.

"In my 20 years as a veterinary nutritionist, I’ve seen vast improvements in our knowledge about pet nutrition, in the quality of commercial pet foods, and in our pets’ nutritional health (other than the unfortunate rise in obesity)," writes Lisa Freeman, veterinary nutritionist and professor of clinical nutrition at Cummings School of Veterinary Medicine at Tufts University.

"However, in the last few years I’ve seen more cases of nutritional deficiencies due to people feeding unconventional diets, such as unbalanced home-prepared diets, raw diets, vegetarian diets, and boutique commercial pet foods."

Questions about pet diets

dog in shopping cart at pet food store
There are so many choices in the pet food aisle, including formulas for specific breeds, ages and health conditions. PongMoji/

In Freeman's blog, she points out that heart disease is common in pets, affecting 10% to 15% of all dogs and cats. Although there is limited information about the role of diet in heart disease, recently some veterinary cardiologists have reported an increased rate of dilated cardiomyopathy (DCM, a disease of the heart muscle), even in breeds that normally don't have the disease, says Freeman.

"There is suspicion that the disease is associated with eating boutique or grain-free diets, with some of the dogs improving when their diets are changed," Freeman writes, saying that the U.S. Food and Drug Administration (FDA) Center for Veterinary Medicine, as well as veterinary cardiologists are investigating.

In response to the uptick of pets affected with dilated cardiomyopathy, the FDA is cautioning owners on buying pet food products that contain peas, lentils, other legume seeds or potatoes as main ingredients. The FDA notes that "high levels of legumes or potatoes appear to be more common in diets labeled as "grain-free," but it is not yet known how these ingredients are linked to cases of DCM."

In a June 2019 update, the FDA announced that 515 cases of DCM had been reported in dogs and nine in cats between January 2014 and April 2019. For the first time, the agency also named the pet food brands most frequently linked with DCM.

There may be a possible connection to a deficiency in an amino acid called taurine. Researchers noticed that many dogs with DCM and a taurine deficiency were more likely to be eating boutique or grain free-diets and diets with exotic ingredients, such as kangaroo, buffalo, bison, peas, tapioca and lentils. It was also noted in dogs eating raw and homemade diets.

The American Veterinary Medical Association issued a warning in December 2018, cautioning owners on feeding their dogs boutique, exotic meat or grain-free (BEG) diets.

Pet food marketing has outpaced the science, and owners are not always making healthy, science-based decisions even though they want to do the best for their pets. The recent cases of possible diet-associated DCM are obviously concerning and warrant vigilance within the veterinary and research communities. Importantly, although there appears to be an association between DCM and feeding BEG, vegetarian, vegan, or home-prepared diets in dogs, a cause-and-effect relationship has not been proven, and other factors may be equally or more important. Assessing diet history in all patients can help to identify diet-related cardiac diseases as early as possible and can help identify the cause and, potentially, best treatment for diet-associated DCM in dogs.

Choosing wisely

dog food and fresh ingredients
For many people, dog food is all about protein and no grains. 279photo Studio/Shutterstock

Because our pets don't go shopping with us, we make their nutrition choices for them. Sometimes owners are inspired by marketing or a vet's reference or by what sounds good to them. Here are some trends in pet nutrition.


The grain-free trend definitely didn't originate in the professional veterinary community, says veterinarian Donna Solomon.

"I speculate that this movement was triggered in part by a pet food company’s advertising campaign to generate a buzz around their unique pet food," she writes in HuffPost. It may also have been triggered by a 2007 incident when melamine, a chemical used in fertilizer, contaminated the wheat gluten used in pet food, causing more than 100 pet deaths. Consumers began looking for a safer alternative.

As humans have shunned grains and gluten, they've passed those choices on to their pets. The dogs' ancestors, they say, didn't eat grains, so the modern dog isn't designed to, either. However, there's little belief among veterinary nutritionists that grains are an issue for pets. Some dogs can have allergies or an intolerance to specific grains, but it's not very common. In fact, says Solomon, some dogs do better on grains because of their high-fiber content.

New proteins

"Chicken has become the 'four letter word' of the pet food industry, with a caution around chicken allergies taking hold of the market," writes Darren Stephens of American Nutrition, a custom pet-food manufacturing company.

"This, combined with owners’ desire to provide their pets with a variety of flavors, has inspired pet food manufacturers to begin offering exotic protein sources including bison, rabbit, kangaroo, and alligator."

Veterinarian Freeman points out that unusual proteins offer a dietary challenge. "Exotic ingredients have different nutritional profiles and different digestibility than typical ingredients, and also have the potential to affect the metabolism of other nutrients."

Small-batch foods

Like people choose to shop at locally sourced shops or restaurants, many turn to small food manufacturers when shopping for their pets. Often these foods might be minimally processed with few ingredients, which can be appealing traits. But larger companies have more funds to devote to research, testing and quality control. They typically have the resources and expertise to make sure the food is up to the nutritional and safety standards your pet needs.

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