**All typos in the quoted case reports have been left in to emphasize the difference between cases written by professionals compared to the public**

Once again, we are tackling the topic of Dilated Cardiomyopathy (DCM) in pets. If you want more information on Taurine, you can read our article "Taurine in Pet Food – Dissolving Misconceptions", and if you would like more information on DCM in regards to the FDA’s most recent report, you can read our article "DCM: A Response to Recent Reports." We don’t want to keep talking about this, but we feel like we must because it keeps coming up every day.

First, I would like to clear up some misconceptions. One of the theories that has been circulating is that ingredients high in these grain free diets, such as legumes and peas, are binding to taurine or other nutrients. However, it is not that difficult to test for nutrient bioavailability. For example, a fecal sample analysis would give a good indication of what is absorbed and what is not and paired with blood sample analyses would further confirm what ends up in the body. Many of the companies said to be linked with DCM do test for these parameters. People rationalizing theories like this are due to the fact that there are no actual claims against these foods.

To all the people claiming that taurine is still the issue, what about foods that contain no taurine that are not being mentioned in these reports? I’m talking about foods like those from the grocery store that are completely corn, wheat and soy based and would literally have no taurine. These ingredients contain the same, if not more, compounds that bind nutrients, including taurine. How would they not cause DCM as well? Something people are also forgetting is that anything that would affect dogs in these foods would also affect cats. Cats are much more sensitive to nutrient deficiencies and if taurine was being bound by peas and lentils then all cats being fed diets with those ingredients would end up with heart and eye defects much faster and more frequently than in dogs.

What we want to talk about in detail are the findings they are using as warnings against grain free diets (link provided below as [1] to the cases referred to by the FDA). Let me point out that there have been no studies proving a link between grain free pet food and diet-induced DCM. All of the articles and reports by the FDA and veterinarians are based on correlations seen in reports given to the FDA. Very few of the reports came before Dr. Freeman’s article about DCM (the original article that started all of this), and most of them were on cats. After her article, there are a lot of reports by pet owners that are not veterinarians reporting DCM cases to the FDA. Many of them claim their dog had DCM due to the grain free food they were feeding because they read the article, with no actual tests to prove this link. For example, this is one of the reports the FDA included in their DCM cases:

“My dog died of heart failure as a result of dilated Cardiomyopathy in (b)(6) 2015. She had been diagnosed 6 months earlier. We had fed her Nature's Recipe Easy to Digest Fish and Potato formula for years. I just read a report that diets containing potatoes may lead to dilated cardiomyopathy. She was an Australian Shepherd, a breed that doesn't usually have this disease [1].”

This case is a story from three years prior and the only reason that the dog’s death has a link with its diet is due to Dr. Freeman’s article. No evidence was provided, and sadly many of the reports are like this one. Some of the reports go into a great deal of detail, describing past medical and nutritional history and cover an array of possible diagnoses, such as in the report below:

“Dr. Jennifer Jones was consulted prior to submission of this report. She would like to be involved in the case review 3 week history of cough treated unsuccessfully with doxycycline and prednisone. 3 day history of inappetence and vomiting prior to presentation to (b)(6) emergency service for dyspnea. Radiographs showed severe pulmonary edema and echocardiogram showed severe Dilated Cardiomyopathy. There was an initial response to diuretic therapy however, he declined and was placed on the ventilator for respiratory support and continued CHF treatment. Attempts to wean off the ventilator were unsuccessful and aquaphoresis was performed. He continued to decline despite aggressive therapy and was euthanized. Infectious disease testing was negative and taurine and carnitine analysis showed adequate levels. Necropsy initially did not reveal a cause for DCM and supported alveolar injury (possibly ventilator related). A re-review of the myocardial histopathology by one of our pathologist showed myofiber vacuoles reminiscent of the changes seen in doxorubicin toxicity. Since the dog had not received doxorubicin, the pathologist recommended culturing the food for Streptomyces peucetius - the bacterium which produces doxorubicin. He also recommended testing for Fusarium spp. a fungus which produces Fumonisin B1, a toxin that produces heart failure in pigs. (b)(6) had been fed Caifornia Naturals Adult - both kangaroo with lentils and venison with lentils along with Milo's kitchen treats. We have samples of these foods from 6/17 but not the original bags from when he was presented 2/17. These samples were provided at he time his housemate, (b)(6) (unrelated, older miniature schnauzer) also presented with severe DCM and CHF. I will enter this dog as a separate affected patient. Both dogs had extensive infectious disease testing which was negative and nutritional amino acid deficiencies were ruled out. Because of this, their unrelated lineages (although the same breed, they were from different lines), different ages but similar time of presentation ((b)(6) had clinical signs at the time (b)(6) was treated, but didn't present with CHF for several months), we are considering common environmental factors which could precipitate DCM, including food contamination or toxin exposure. We have plasma, serum, urine and myocardial tissue samples (latter only for (b)(6)) stored at -80 Celsius in addition to food and treat samples [1].”

This report attracts much more respect since it is so comprehensive. It states that there are a couple of possible causes and that they kept tissue samples and food for further testing. It should be noted that this case was submitted before Dr. Freeman’s article. At this point the veterinarian was trying to find a diagnosis and said that the food was one of the many factors they were considering. Now that the link has been stated between grain free foods and DCM, many of the cases simply say that the dog has DCM because of their diet, with no supporting evidence or health history about the animal in question. For example,

“Decreased exercise tolerance. Vet heard mumur . X-ray showed enlarged heart. Pro bnp showed heart issue. Echo showed suspect diet induced dilated cardiomyopathy [1].”

“My pet (b)(6) was diagnosis (06/2018) with dilated cardiomyopathy [1]”

“DCM and CHF Taurine not measured [1].”

And another:

“(b)(6) (half sister; (b)(6) - (ICSR) of 2063133) diagnosed with DCM and CHF so screened by RDVM for BNP which was elevated. Evaluated at (b)(6) 2/1/19. ARVC/diet-induced DCM with ventricular arrhythmia. Diet changed to Royal Canin Early Cardiac and will re-evaluate in 3 months I have diet sample. 3 other dogs in household (1 had normal BNP, other 2 not yet evaluated) [1].”

This last case is frustrating because the dog in question has a relative that was diagnosed with DCM as well. This would point to a potential genetic predisposition rather than diet induced. As well, one of the other dogs in the household had normal levels. Another point I would like to make is that, like the case above, a large amount of the cases are inconclusive. For example, they changed the dog’s diet and have not gotten results yet as to whether it helped with the DCM.

Ironically, one of the most comprehensive case studies is the first one on the report. Because this report is chronological, it was submitted back in 2014, long before Dr. Freeman’s article. It goes into much detail about the patient and has results from changing the diet. The prescription diets often state that they are not meant to be fed long term since they do not meet the minimum nutritional requirements. However, many veterinarians recommend feeding them for long periods of time which, as you can see from the case below, can be severely detrimental to the health of the dog eating it. These are also some of the foods that Dr. Freeman and other veterinarians are telling people to switch to.

“Hills Prescription U/D caused developmental cardiac deficiencies in our dog (b)(6). We believe it is unsafe to be used in canines over any length of time. We have extensive medical records for proof of this fact. (b)(6) was diagnosed with urolithiasis in March 2007 and after surgery was prescribed Hill Prescription Diet U/D dry and canned food. This was his only source of nutrition along with baby carrots as treats. On May 15, 2013, he developed an unusual cough which was continuous for the entire afternoon and evening. He woke up coughing at 3:00am as well. The next day I took him to the vet we were seeing at that time. He received an ECG after the vet heard a gallop heartbeat. He was diagnosed with dilated cardiomyopathy and we immediately went to (b)(6) to the cardiology department. At that time, he was diagnosed with congestive heart failure and started on enalapril, LASIX, taurine, L-carnitine , , and fish oil. His diet was changed to Royal Canine, low purine and Hill's L/D at the recommendation of the (b)(6) Nutrition Department. At that time, his cardiologist, Dr (b)(6), suspected that his heart disease was nutrition related. Hill U/D does not have enough of the proper nutrients in it to allow for adequate heart development and function. We knew that several months would have to pass before we knew for certain if this was indeed the case. We took him back to the cardiologist in August and he was showing some mild improvement. We took him again and February and the improvement in his heart function was astonishing. He still has dilated cardiomyopathy but it is improving vastly with his dietary changes. The improvements are not seen with heart medications alone according to his medical records. His long term prognosis is still uncertain but continued improvement is hoped for. It is not common knowledge among general veterinarians that this food is unsafe for long term use.
This food should come with a warning label at the very least. I request that it be pulled from the market as it is the catalyst for heart disease and unsafe for canine consumption [1].”

Some of the cases don’t even mention DCM in their report, such as the one below:

“(b)(6) presented at (b)(6) for difficulty breathing/ enlarged heart. (b)(6) was diagnosed on Thursday with an enlarged heart with RDVM. RDVM sent (b)(6) home with instructions to limit activity. (b)(6) collapsed twice this weekend. Once was when (b)(6) was outside walking and saw a squirrel and the other episode was when (b)(6) saw the neighbor and came running to neighbor. (b)(6) has been eating normal, but (b)(6) did have soft stool yesterday. (b)(6) has continued to breathe heavy throughout the weekend and has been experiencing coughing/ barking episodes of discomfort. (b)(6) is up to date on vaccines. (b)(6) littermate was diagnosed with a heart murmur at 1.5 years old [1]”

…and some don’t even mention heart disease in general:

“Hx of suspected food allergies characterized by moist dermatitis. In 2013 owner switched to a grain-free diet. Dermatitis resolved. Multiple hospitalizations for non-obstructive GI foreign bodies - none requiring surgery [1].”

“Presented as ER case after evaluation at (b)(6) the previous afternoon. Owner report distended and uncomfortable stomach, with a decrease in activity and an increase in vagal collapse episodes, that have been associated with bowel movements. (b)(6) appetite is also decreased and he vomited after one collapse episode. The collapse episodes have been occurring more frequently over the last few days, with at least 1 occurring each day. (b)(6) removed 1500ml of fluid from (b)(6) abdomen and gave him 2mg/kg injection of furosemide [1]”

In the above case, it is not impossible that the fluid build-up in the abdomen is linked to a heart disease, but the heart is not mentioned anywhere. Plus, there are other potential causes that could result in abdominal fluid and discomfort.

There are also several cases of DCM being diagnosed right after surgery or anesthesia, seen in the example cases below [1]. These should be considered as a possible factor since anesthetic and infection due to surgery are known causes of DCM in humans [2,3].

“She was on the Chicken based raw food. Not doing well after castration, after investigating had DCM on rads and ultrasound. Was euthanized due to poor prognosis and fractional shortening of the heart was like 5% [1].”

“Products: (1) Taste of the Wild Prey Angus Beef Limited Ingredient Formula for Dogs (Grain-Free) and (2) Taste of the Wild Pacific Stream Canine Recipe with Smoked Salmon Dog Food (Grain-Free): A 2 y/o, female Great Dane, (b)(6), 145 lbs, not spayed, no diagnosed allergies, and no pre-diagnosed conditions, experienced red skin and itchiness throughout her body in mid 12/2017. The reaction subsided within a few days, but reoccurred a couple of weeks later in late 12/2017, and subsided in a few days. No healthcare was sought. In 05/2018, (b)(6) was taken to (b)(6) for pre-op tests to prepare for spaying, and test results, chest x-ray and electrocardiogram were negative for anomolies. On 07/05/2018,follow-up at (b)(6) disclosed low blood platelets and (b)(6) was diagnosed with Mitral Valve Dysplasia. (b)(6) was considered stable, so no medication was prescribed, and a follow-up electrocardiogram was recommended for 12/2018. On (b)(6) at 1:00 am, the Complainant heard the loud cough, monitored the dog and on (b)(6) brought (b)(6) to (b)(6)l, where (b)(6) administered a chest x-ray and tests confirmed Congestive Heart Failure and on the same day, (b)(6) was admitted to (b)(6) where (b)(6) was diagnosed with Cardiomyopathy due "to taurine deficiency from a grainfree diet". She was treated and released on (b)(6) with Rx Lasix and Vetmedin and is lethargic. She has a follow-up appointment in two weeks with Dr. (b)(6). The Complainant (owner) believes that these two Taste of the Wild Grain-Free dog foods caused (b)(6) conditions. She has fed Taste of the Wild Pacific Stream Canine Recipe with Smoked Salmon Dog Food to (b)(6) since she was born and changed food to the Angus Beef flavor in 01/2018, due to what she believes was an allergic reaction, itchy ears, and red skin, that she began noticing in 12/2017, that she believed was Continued from Complaint Description above: caused by (b)(6) consumption of the Pacific Stream product. She contacted the manufacturer, Schell & Kampeter DBA Diamond Pet Foods, who provided her with a different Lot of the Pacific Stream product. She fed (b)(6) again, and the symptoms reoccurred. The Complainant has another 6 y/o, female, Great Dane, (b)(6), who has been eating the Pacific Stream Smoked Salmon everyday for years and has not experienced any symptoms. The Complainant stated that she fed both dogs 2x a day only the Taste of the Wild dog foods reported. They both are supervised when they go out in the yard and she stated that nothing could have been picked-up there. Complainant does not have any product codes as she used all of the Pacific Stream product and returned the Angus Beef bags to the retail store for reimbursement. INJURY/ILLNESS: lethargy, red skin and itchiness throughout body; 1 loud cough [1].”

“DCM and arrhythmias diagnosed at time of GDV surgery so unclear if sepsis/post-op or true DCM. Had recheck echo 10/31/18 and still has DCM. Taurine pending. Owner has changed diet to Royal Canin Boxer [1].”

“(b)(6) went into Congestive Heart Failure that required emergency interventions over the weekend. 7 days prior to emergency admission he had a sedated tooth extraction which he tolerated well. He had a persistent cough after the surgery (to which I was told was related to the intubation). His cough increased and respiratory distress increased, and so I took him to emergency. There they discovered an enlarged heart/severe tachycardia/fluid on his lungs. He was kept in emergency for 24 hours to stabilize him and then brought home on lasix and pemobeden. He followed up with a veterinary cardiologist 2 days later to confirm diagnosis and move forward. His ECHO confirmed DCM. He has been started on 5 medications, and 2 supplements (taurine and carnitine). Taurine level tests were sent off and expected back in 2 weeks.
(b)(6) has exclusively eaten a diet of Zigniture Grain Free Kangaroo Food since he was a puppy. This is the concern I am reporting. It is my understanding that there is concern that grain free/exotic protein dog foods have been linked to DCM in dogs without a genetic predisposition for it [1].”

It is disturbing to read some of the case reports that go into detail about treatments that did not work and lead to the dog dying. According to these reports, several dogs have been diagnosed with diet-induced DCM and usually treated with a diet change/and or taurine supplementation, as in the cases below. Our biggest fear is that there is another issue going on causing these heart diseases that are being misdiagnosed as diet-induced DCM when changing the diet does not improve the patient’s health. Overlooking a diagnosis could lead to many dogs dying from a problem that could be treated.

“Patient was transferred from rDVM to the emergency service for further care for dyspnea and suspected CHF on 7/13/18. Patient severely dyspneic on presentation and not stable enough for echo until the next day. Patient treated for CHF and improved. Echocardiogram showed findings consistent with dilated cardiomyopathy with severe LV dilation and severe systolic dysfunction. The owner had been feeding Acana lamb and apple diet for years to both of her dogs. Taurine level was submitted and patient was placed on taurine supplementation with recommended diet change. Patient was able to be discharged from the hospital a few days later and had been doing pretty well at home but did present to ER for possible syncopal episodes on 8/3/18; owner declined most diagnostic tests recommended but patient clinically appeared stable and was diagnosed with a corneal ulcer at that time. Patient presented to the emergency service this morning DOA - patient was reportedly dyspneic and died during transport to the hospital [1].”

“(b)(6) a German Shepherd Dog stopped eating and was diagnosed with dilated cardiomyopathy. He did not respond to treatment including taurine supplementation and died 5 weeks later. He was treated by cardiologist Dr. (b)(6). According to Dr. (b)(6) taurine levels were not abnormally low but just at the low end of normal. (b)(6) along with a female GSD about the same age and his son who was 4 years at the time of (b)(6) death were on the same grain free diet for 4 to 5 years. At first various varieties of Merricks then for the last 2 years various varieties of Kirkland Natures Domain ((b)(6)). Specifically 70% Salmon, 15% Beef and 15% Turkey. The other 2 dogs have not shown any adverse effects [1].”

“Presented for sudden onset of lethargy, exercise intolerance, not eating well. Performed bloodwork, x-rays, ultrasound, ECG and report from Cardiologist. Was diagnosed with Dilated Cardiomyopathy by Cardiologist. Has been fed a grain free dog food her entire life and with new research developing about these diets being linked to DCM it was recommended to stop the food and run a Taurine blood level. Heart medications were started. Did not respond well to treatment and was humanely euthanized 2 weeks later [1].”

There are many different causes for heart disease, even DCM in particular. Heart disease is the leading cause of death in humans, so you can’t blame any one thing for every case. DCM is a bit of a vague term and encompasses many different causes and specific diseases. This makes it difficult to believe that there is a certain ingredient or group of ingredients causing all of these cases.

People will say that we picked the cases that supported our side of the argument, but we are just presenting a thought process. If you disagree with us we would love to see what cases you see as evidence, and not just a case of a dog with heart disease that happens to eat grain free food. It is up to you as a responsible pet owner and intelligent human being to read through these cases and articles yourself and make your own decision whether the claims are substantiated or not. We do not want to tell you what to think but bring some important points to light so you can make an educated decision of your own.

[1] Dilated Cardiomyopathy in Dogs & Cats: Complaints Submitted to FDA-CVM, https://www.fda.gov/media/128303/download

[2] Dilated Cardiomyopathy (DCM), https://www.heart.org/en/health-topics/cardiomyopathy/what-is-cardiomyopathy-in-adults/dilated-cardiomyopathy-dcm

[3] Stress-induced cardiomyopathy after general anesthesia for total gastrectomy -A case report, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2872848/?fbclid=IwAR0_oyJtvG6w1Y2KJHXURphic3gM_YHK2gUovzWbNaVesTRb_7ggnO0qrmY