Grain-Free Dog Food and DCM

Is there a connection between grain-free dog food and Dilated Cardiomyopathy (DCM) ?

 Spoiler Alert. There is currently no evidence linking grain-free dog foods to DCM and no evidence that grain-inclusive dog foods prevent DCM.

Why DCM made the news.

In 2018, the U.S. Food and Drug Administration (FDA), acting on input from a group of veterinary researchers, started investigating whether the rise in popularity of grain-free dog foods had led to an increase dilated cardiomyopathy (DCM) or heart disease in dogs.

Four years later, the FDA has not found a link between diet and dilated cardiomyopathy. The negative publicity and Veterinary response surrounding this issue, resulted in a substantial decrease in sales for the grain free dog food market.

That sounds simple enough, however a tangled web of industry funding and interests appears to have influenced the origin, data collection, and direction of the FDA study, according to internal FDA records.

So what happened?

DCM has been a common disease in dogs. In 2018, veterinarians noticed an uptick in dogs showing signs of DCM and as concern grew, more Veterinarians paid attention and reported every possible case. Veterinarians then started pointing the finger at “grain-free” and “boutique” diets with unique proteins. The Food and Drug Administration (FDA) became involved and a news media ran an article indicating which brands and products dogs were consuming at the time. What followed was a fairly drastic about face in veterinary and public opinion on the inclusion of grain in dog food.

DCM is essentially heart disease in dogs, found more frequently in breeds like Dobermans, Boxers, Great Danes, Cocker Spaniels and Golden Retrievers. DCM is a condition in which the heart muscle becomes thin and ineffective at pumping blood, resulting in a very enlarged or dilated heart. It affects approximately 1% of the canines in the U.S.

A Dog food produced without wheat, corn, rice or oats and other grains is considered “grain free”. They have been extremely popular since before 2000 when pet parents became aware of the high starch level (carbohydrates) and sugar inherent in manufactured kibble diets most of which included the heavy use of grains.

Natural dog diets of raw or fresh cooked are naturally grain free. But grain free or low grain doesn’t always mean no or low carb. Quality meat proteins are expensive and at some point the inexpensive replacement for grains became high amounts of lentils, peas, white potato or quinoa.

In 2018, when veterinarians began noticing and reporting more signs of DCM, they also found low levels of taurine. Possible theories were that low taurine or poor taurine absorption could be the culprit. The Food and Drug Administration (FDA) became involved in July of 2018, working in partnership with the Pet Food Institute. It is important to note the fact that this is a lobbying group whose members are in the pet food industry, representing corporations like Mars Petcare, Smucker’s, Royal Canin, General Mills, Colgate-Palmolive) and Nestle-Purina.  It is equally important to note that Mars Petcare produces Pedigree, Iams and Nutro and owns the Royal Canin Division producing the Royal Canine line, Eukanuba and more recently Nom-Nom. Nestle-Purina produces Purina One and Purina Pro Plan, Colgate-Palmolive produces Hill’s Science Diet and General Mills purchased the Blue Buffalo brand in 2018.  And just so you have all the info, you should know that Mars Petcare also owns the Blue Pearl chain of emergency and specialty vet care clinics Banfield and VCA Animal Hospitals.

 The FDA reviewed 16 dog food manufacturers having ten or more cases of DCM reported while dogs were eating that food. More than 90% of those diets were “grain-free” and 93% contained peas or lentils. This quickly transitioned to “fact’ and veterinarians began advising their clients to switch to a grain inclusive diet. Grains do NOT contain taurine and it is unclear how feeding grain became the Veterinarians solution to the problem.

The FDA released an updated list of dogs affected by DCM in late June of 2019. 305 dogs were listed, 73% were breeds already known to have a genetic predisposition for DCM and 61% also had other diseases which could have contributed to cardiac disease like mitral valve degenerations, lyme disease and hypothyroidism. Additionally, the FDA report listed only small dog food brands and strangely did not include the 49% of brands made by six of the largest pet food manufacturers in North America. Only smaller pet food manufacturers made the list. At the time, these were some of the strongest up and coming brands (notably Acana, Zignature, Taste of the Wild, 4 health, Earthborn Holistic, Blue Buffalo, Fromm, Merrick among others).  These companies then saw huge losses in sales revenue and jobs as a result. Note: General Mills purchased Blue Buffalo in 2018 and Mars Petcare has purchased Acana and Orijen in 2022.

In 2020, a review of the current literature showed many flaws in the DCM studies and noted sampling bias, inconsistencies, too many variables and the known genetic predisposition in certain dog breeds.

In 2021, Tufts University published a study of the diets associated with DCM vs. the diets not associated with DCM. Their conclusion was that peas represented the greatest difference between them. There were more results associated with peas but ultimately more research is needed.

Additional studies have been conducted with potentially flawed and in some cases heavily misleading or biased data.

By 2022 sales of grain-free dog foods had dropped by $60 million and grain-inclusive sales rose by $700 million. 

A six-month investigation by 100 Reporters has found that veterinarians who prompted the FDA to consider diet have financial and other ties to the leading sellers of grain-inclusive pet foods. Additionally, agency records show that for the initial study, some vets were instructed to submit only dilated cardiomyopathy (DCM) cases that implicated grain-free, “exotic” or “boutique” pet foods.

A class action lawsuit has been filed against Hill’s Pet Food and others claiming they were involved in a misinformation campaign to make veterinarians and pet owners believe grain-free pet foods were dangerous and linked to canine hear disease. This suit includes extensive details on how the defendant allegedly fabricated the grain-free pet food link to DCM.

So where are we today?

Ultimately, we are still searching for answers.

In 2020, the U.S. Food and Drug Administration (FDA) concluded that there is no scientific evidence that a grain-free diet causes canine dilated cardiomyopathy (DCM). 

The agency outlined the multiple potential factors that can, alone or in combination, contribute to dogs developing this rare and scientifically complex disease. The agency concluded that there is nothing inherently unsafe about a grain-free diet and that a grain-inclusive diet will not prevent DCM.

Dr. Steven Solomon, director of the FDA’s Center for Veterinary Medicine, acknowledged that the “complex scientific messaging” on DCM and diet has contributed to misinterpretation about the safety of a grain-free diet.

In December 23, 2022 the FDA announced it did not intend to release further public updates until there is meaningful new scientific information to share.

Some Veterinarians continue to recommend against grain-free without clarifying it is not the lack of grains that is the problem but more than likely the heavy use of legumes/peas (high starch) that could be the issue. Purchasing a higher quality, low carb or opting for a fresh, whole food diet is probably the better option.  I know this because I hear from my puppy parents that their vet tried to switch their new puppy to Hill’s Science Diet, Royal Canin or one of the products they sell in the lobby of their practice. When asked why these products were better than what the breeder was recommending, they were told it was because the companies behind these big brands had the money to do the large field trials. That’s it. No discussion about better ingredients or sourcing, just that food trials were conducted.

The biggest takeaway from the “Grain-Free & DCM” discussion is that a grain-free product is not bad for your dog. The inclusion of too many legumes/peas in place of quality meat protein is most likely not good for your dog. We know starch and sugar should be minimized in their diet so choosing a quality product with meat ingredients first, no or low grain and low carbohydrates is key.