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Pet Wise: Exploring links between grain-free diets and cardiomyopathy in dogs

For almost 30 years there have been trends and fads regarding how we feed our pets.

Raw food diets became popular after the publication of Dr. Ian Billinghurst’s book “Give Your Dog a Bone” in 1993. However, there is a serious risk from feeding raw food diets that may be contaminated by bacteria that can sicken both pets and humans. Commercial pet food recalls stimulated well-intentioned pet owners to create home-made diets found on the internet and in pet food recipe books that were often unbalanced, nutritionally deficient and could cause serious long-term health problems for dogs and cats.

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Recently, the US Food and Drug Administration initiated an investigation of a possible link between grain-free pet foods and Canine Dilated Cardiomyopathy (DCM), a type of canine heart disease that affects the heart muscle. The hearts of dogs with this condition have a decreased ability to pump blood which often results in congestive heart failure. Large and giant breeds of dogs have a predisposition to DCM. These breeds include Doberman pinschers, Great Danes, Newfoundlands, Irish wolfhounds, boxers, and St. Bernards. DCM is less common in medium and small breeds, However, English and American cocker spaniels are also predisposed to this condition.

The American Kennel Club sent an email to owners of AKC registered dogs on June 28 with the following message from Dr. Jerry Klein, the chief veterinary officer of the American Kennel Club regarding the ongoing FDA investigation. “The FDA is investigating a potential dietary link between canine dilated cardiomyopathy (DCM) and dogs eating certain grain-free foods, The foods of concern are those containing legumes such as peas, or lentils, other legume seeds, or potatoes listed as primary ingredients. The FDA began investigating this matter after it [began] receiving reports of DCM in dogs that had been eating these diets for a period of months to years. DCM is not considered rare in dogs, but these reports are unusual because the disease occurred in breeds of dogs not typically prone to the disease. The AKC email bulletin noted that” between January 1, 2014 and April 30, 2019 the FDA received 524 reports of DCM (515 dogs, 9 cats) and most reports were submitted after the FDA’s first public alert in July 2018. The total number of affected pets is greater than 524 because some reports included multi-pet households.”

The reports submitted to the FDA covered a wide range of breeds that included many that had no known genetic predisposition for DCM. “When early reports from veterinary cardiologists indicated that recent, atypical cases in breeds like golden retrievers, Labrador retrievers, whippets, bulldogs, and Shih Tzus all consistently ate grain alternatives in their diets, the FDA took notice.

The FDA’s July 2019 update on diet and canine heart disease involved examining labels of dog food products in reported DCM cases to determine if the foods were “grain-free (no corn, soy, wheat, rice, barley or other grains), and whether the foods contained peas, lentils, chickpeas, or potatoes (including sweet potatoes.) Their report states that more than 90% of the foods reported in DCM cases were grain-free, 93% of reported foods contained peas and/or lentils, and 42% contained potatoes/sweet potatoes.

The FDA’s July update includes the names of dog food brands that were named were named 10 times or more in reports submitted through April 30. Most reports were for dry dog food, but raw, semi-moist and wet foods were all represented.

· Acana (67 reports);

· Zignature (64);

· Taste of the Wild (53);

· 4Health (32);

· Earthborn Holistic (32);

· Blue Buffalo (31);

· Nature’s Domain (29);

· Fromm (24);

· Merrick (16);

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· California Natural (15);

· Natural Balance (15);

· Orijen (12);

· Nature’s Variety (10);

· Nutrisource (10);

· Nutro (10);

· Rachel Ray Nutrish (10).

Dr. Lisa M. Freeman, a veterinary nutritionist and professor at the Cummings School of Veterinary Medicine at Tufts University presents the following information that might be helpful for dog owners to understand the issues regarding diet choices for their pets. She believes” “It’s not just grain-free.”

“I am calling the suspected diets, ‘BEG’ diets- Boutique companies, Exotic ingredients, or Grain-free diets. The apparent link between BEG diets and DCM may be due to ingredients used to replace grains in grain-free diets such as lentils or chickpeas. But it may also be due to other ingredients commonly found in BEG diets such as exotic meats, vegetables, and fruits. In addition not all pet food manufacturers have the same level of nutritional expertise and quality control, and this variability could introduce potential issues with some products.”

It was thought that low taurine levels were associated with DCM and dog owners thought that by supplementing their dog’s diet with taurine that it would reduce the risk their risk for heart disease. According to Dr. Freeman most dogs diagnosed with DVM do not have low taurine levels. At her hospital all dogs with DCM have their taurine levels measured and more than 90% of the patients with DCM in which taurine has been measured have normal levels and the majority were eating BEG diets. Dr. Freeman suggests that “something else is playing a role in most cases- either of a deficiency of a different nutrient or even a toxicity that may be associated with BEG diets.” And given the lack of quality control for dietary supplements you can introduce new risks to your dog if you give a supplement without evidence that she needs it” Freeman also warns owners that raw and homemade diets are not safe alternatives. Dogs eating these diets have been diagnosed with DCM at her hospital.

Dr. Freeman advises dog owners to watch for early signs of heart disease: weakness, slowing down, less able to exercise, shortness of breath, coughing, or fainting. If you notice these signs your dog needs to be checked by a vet who will listen for a heart murmur or abnormal heart rhythm, but not all dogs with DCM have any changes that can be heard with a stethoscope. Other tests may include x-rays, blood tests, electrocardiogram, and ultrasound - the test of choice to diagnose DCM. Owners will need to tell the vet what they are feeding the dog and bring that list to every appointment.

Dr. Steven Rosenthal, a Maryland- based veterinary cardiologist has been in practice for 25 years and has been collecting data regarding this perplexing health problem.

He states: “Over the past few years we have seen an increase in the incidence of DCM in dogs that were in breeds of dogs that were not perceived to be genetically predisposed to this disease. Many of these pets were eating boutique diets that were listed as grain free. Initially we were concerned about a deficiency in taurine as many golden retriever dogs had low blood taurine levels. Subsequently we have found numerous other dogs with normal taurine levels which has complicated the question of why these dogs developed heart disease. Taurine is still on our radar as it can still be related to development of this disease. We would suggest using diets that go through vigorous feed testing as well as diets where a certified veterinary nutritionist (American College of Veterinary Nutrition or ACVN ) are part of the team formulating the diet. Affected dogs were on diets that most often did not meet these standards. Dilated cardiomyopathy can be a devastating and life threatening disease so being cautious with the choice of diet can help reduce the risk of this disease developing in pets.”

If you have concerns regarding your pet’s health or diet, consult your veterinarian or veterinary nutritionist.

The FDA encourages pet owners to report cases of dogs and cats with DCM that they suspect to be linked to diet by using the Safety Reporting Portal.

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Iris Katz serves as a member of the board of directors and as an educational facilitator for the Humane Society of Carroll County. Her Pet Wise column appears in Life & Times on the third Sunday of the month.

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