Canine morbidity and mortality have been found to be impacted by the health of the heart. Dilated cardiomyopathy is the second most popular cardiac disease and with DCM, “dilation of the cardiac chambers reduce leading to systolic function and can progress to heart failure, arrhythmias, and sudden death” as per the literature review in this 2019 study.
Understanding DCM in Dogs
DCM has been historically been classified as a hereditary cardiac disease.
Below is a quick video explaining DCM in humans;
The study, led by researcher Dr. Lisa M. Freeman, and his team formed the basis for the FDA’s announcement in 2018 that it was investigating the link between DCM and grain-free diet in pet food.
Dr. Lisa, et.al’s team looked at the cases of 524 dogs diagnosed with DCM between December 1, 2010, and November 30, 2017. The hospital where the study was conducted saw an increase in the number of cases of DCM, from 2.4 cases/10,000 dog-years in 2010 to 11.8 cases/10,000 dog-years in 2017.
Over half of the dogs in the study were being fed a grain-free diet and almost 90% of those diets contained peas or lentils.
The FDA reported that out of the 524 dogs diagnosed with DCM, 91,93,89 were fed diets that were grain-free, with lentils/or lentils, and with peas respectively. Grain-free diet is therefore not the only diet linked to DCM. Lentils and peas are also some of the biggest to blame for diet-caused DCM or non-hereditary DCM.
Further, different dog breeds were found to have varying susceptibility to DCM with the control diet that included grains, peas, lentils, and potatoes.
Unfortunately, peas, chickpeas and lentils are some of the mostly used replacement of grain in the grain-free dog food;
As shown in the Watt Global Media report on dog and cat food ingredients; 50.8% of grain-free ingredients rely on peas for dry dog food and 45.9% of dry cat food rely on peas as well to replace grains in their diets.
From the chart above, only sweet potatoes wasn’t linked to highly-significantly p-value in its link with DCM.
The chart below shows breeds such as Golden Retrievers, Great Danes, and Labrador Retrievers were not as likely to develop DCM.
The study did have some limitations in that it was based on client-owned dogs seen at one referral hospital and may not be generalizable to all dog populations. In addition, the possibility of recall bias cannot be ruled out as owners were asked to recall what their dog was fed in the past.
Despite these limitations, the study provides important information linking DCM to diets that are grain-free and contain peas and lentils. The FDA continues to investigate this potential link and is working with pet food manufacturers to provide more information about the ingredients in their products.
How large is the grain-free market in the US?
A 2019 study that calculated the size of a grain-free market used the formula, used the dollar sales volume;
grain-free sales/price per bag/12 months/# of dogs = 10%
The report noted that the report indicating the market size of the grain-free pet diet could have been underestimated and may be as high as 40%. In comparison, only 4.1% of the dogs were diagnosed with DCM in 2019 the period the grain-free market was estimated to be 40%.
The report relied on pet sales data in the US as provided by Nielsen Research Group.
What DCM Studies say:
Male Dogs are more likely to develop DCM than female dogs:
In a study published in J Vet Med Sci in 2016, male dogs were found to have up to 1.2 times higher odds of getting DCM compared to their female counterparts. Male dogs have been identified as the gender most likely to develop the disease in other studies as well.
The 2016 study did not study a larger sample and mostly included small-size, including Japanese, dog breeds finding Cavalier King Charles Spaniel, Maltese and Pomeranian as the most prevalent breeds with the disease.
Larger breeds are more likely to develop DCM:
FDA study found that larger breeds were more likely to develop DCM than smaller breeds.
Dog breeds such as Boxers, Newfoundlands, Irish Wolfhounds, and Great Danes were some of the breeds identified in the study as being more likely to develop DCM.
Mix-breed dogs are more likely to develop DCM:
The study also found mixed-breed dogs to be among the highest and most susceptible group of dogs to develop DCM. breeds are at risk for DCM?
The FDA identified the following breeds as being more likely to develop DCM:
Which type of food was covered in the FDA study?
More than 500 food formulations were covered in the FDA study and 452 or more than 90% of all DCM-reported-linked food were dry dog food.
Which brands were mentioned to be linked to DCM?
Acana is a pet food brand that is manufactured by Champion Petfoods. The company was founded in 2002 and is based in Alberta, Canada. It markets itself as the #1 food to put dog rescues first. I suppose they are trying to say they are cheap and care about a significant amount of food dog rescues need to support a growing population and can serve them better with affordable kibble…cheap is expensive. They also have operations out of Kentucky here in the US.
Zignature (64 cases): Zignature is a pet food brand that is manufactured by Vested Interest in K9s, Inc. The company was founded in 2010 and is based in the United States.
The company markets its pet food brands as the limited-ingrediet diets dogs can rely on.
After the FDA revelation linking Zignature dog food to DCM cases, the company released a statement shown in the screenshot below;
They also went further to commission a study along with Pets Global which they reported in June 2020 concluding that “plasma and whole blood taurine concentrations increased as the dogs were eating Zignature® Kangaroo Formula, suggesting this brand’s feeding trial did not contribute to any negative health conditions, including dilated cardiomyopathy, and in fact, all dogs on the study thrived on the diet as evidence of their physical performance during their activities and training throughout this six-month study.”
You can read the entire study here
Three things that make me doubt this company and the quality of their ingredients and specifically reputational risk shown by;
- Lack of company address on their website here. AAFCO and WSAVA have specifically specified to avoid companies with limited corporate profile and lacking known addresses. This is a way companies try to avoid accountability by not showing any real people behind the brands.
- Went ahead and launched their own study to refute the FDA study and other credible peer-reviewed studies that have linked Zignature Kangaroo Formula to DCM. This goes to tell you that they are not interested in listening to science to make their brand better.
- ‘Globally’ sourced ingredients tagline on their website tells you that they may be sourcing cheap ingredients from countries such as China known to include poisonous ingredients with minimal regulations.
Overall, we give Zignature brand a very bad review of less than 10 and in our ‘red list’ labels you should avoid.
Below is the entire DCM dog food list to look out for and avoid;
- Acana (67 cases)- in Canada and US and also linked to Orijen
- Zignature (64 cases)- in the US and retails both wet and dry cat food
- Taste of the Wild(53 cases)
- 4Health(32 cases)
- Earthborn Holistic(32 cases)
- Blue Buffalo (31 cases)
- Nature’s Domain(29 cases)
- Fromm(24 cases)
- Merrick (16 cases)
- Californian Natural(15 cases)
- Natural Balance(15 cases)
- Nature’s Variety (11 cases)
- Nutrisorce (10 cases)
- Orijen (12 cases)
- Nutro(10 cases)
- Rachel RayNutridish(10 cases)
Combined, there were 16 brands that contributed to over 400 of the total 524 cases.
The most popular grain-free diet among all DCM-affected dogs was Acana, followed by Zignature, Taste of the Wild, 4Health, and Earthborn Holistic.
While grain-free diets are not the only possible cause of DCM, they may be a risk factor for certain dogs. The FDA is still investigating this potential link and will provide updates as more information becomes available.
Some possible diet causes of DCM in Dogs
One theory is that some grain-free diets may be low in an amino acid called taurine. Taurine is found in animal muscle meat, including organ meats and seafood. It’s also added to some pet foods as a supplement. Taurine deficiency has been linked with DCM in dogs, although the mechanism isn’t well understood.
Another theory is that dogs may be more likely to develop DCM if their diet contains a high proportion of legumes like peas, lentils, and beans instead of grains. This is because legumes are a relatively new addition to pet foods, so dogs may not have the same ability to digest them as they do grains.
It’s also possible that the increasing popularity of grain-free diets has led to a change in the overall nutritional content of pet foods, which may be a contributing factor.
There may be directly identifiable symptoms earlier in the disease states. Heart murmurs may, however, be present in asymptomatic dogs with early myocardial changes, although this is not common. Your veterinarian may detect an irregular heartbeat or arrhythmia on a routine physical examination or during a wellness visit. However, some dogs with DCM have few or no clinical signs in the early stages of the disease.
The most common sign of DCM in dogs is exercise intolerance. This means that your dog tires easily and may be reluctant to go for walks or play. You may also notice that your dog is coughing, has difficulty breathing, or experiences an increased heart rate at rest. As the disease progresses, your dog may develop fluid retention, which can lead to an enlarged abdomen (known as a pot-bellied appearance) or difficulty urinating. In severe cases, your dog may collapse or go into sudden cardiac arrest.
Symptoms of DCM in Dogs:
Studies have shown that ‘The most common symptom that we see in dogs with DCM is exercise intolerance or tiring more easily during walks or other activities.” Other signs of DCM include coughing, difficulty breathing, and a loss of appetite.
As the disease progresses, dogs may collapse during walks or even at rest. A veterinarian may also hear an abnormal heart rhythm or murmur when listening to the dog’s chest with a stethoscope. An x-ray of the chest will often show an enlarged heart.
Diagnosis of DCM in dogs:
There is no one test that can definitively diagnose DCM, so your veterinarian will need to take a detailed history and perform a thorough physical examination. Your dog will also need to undergo some diagnostic tests, which may include:
-A complete blood count (CBC) to check for anemia or inflammation
-A biochemical profile to assess organ function
-An electrocardiogram (ECG) to evaluate heart function
-X-rays of the chest to look for heart enlargement or fluid accumulation
-Echocardiography to assess heart function and structure
-Holter monitoring to check for arrhythmias
-Blood pressure measurement
Treatment of DCM in Dogs
There is no cure for DCM, but treatment can help to improve your dog’s quality of life and extend their lifespan. Treatment will be focused on managing the symptoms of the disease and supporting heart function. In some cases, treatment may also include dietary changes. Your veterinarian will work with you to develop a treatment plan that is right for your dog.
The goal of treatment is to improve your dog’s quality of life and to slow the progression of the disease. Treatment will be based on your dog’s individual needs and may include:
- -Weight management: If your dog is overweight, your veterinarian will recommend a weight loss program.
- -Exercise restriction: Your dog will need to exercise less to help reduce the workload on their heart.
- -Medications: Your dog may be prescribed medications to help improve heart function and relieve symptoms. These may include diuretics, ACE inhibitors, beta-blockers, and antiarrhythmics.
- -Supplementation: If your dog has a taurine deficiency, they may be prescribed taurine supplements.
- -Dietary changes: Your veterinarian may recommend a change to your dog’s diet. This may include switching to a grain-free diet or adding more legumes to their diet.
- -Heartworm prevention: If your dog is not already on heartworm prevention, they will need to start taking it to help protect their heart.
- -Regular check-ups: Your dog will need to see their veterinarian for regular check-ups to monitor their condition and adjust their treatment plan as needed.
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Hi there! My name is Alex Landy, one of the co-founders here at Our Pets HQ and a parent to a small-breed Yorkie. I am a published author of two books on dog breeding and currently write on various pet-related blogs about caring for dogs. I am a parent of two daughters and live outside Boston where I spend a lot of time with family and serve in different breeding clubs. You can reach me at firstname.lastname@example.org