Ongoing research is shedding light on the potential link between diet and heart disease in pets. Here’s what we know, and why you should stay informed.
Heart disease affects 10-15% of all dogs and cats, with a higher percentage in some breeds, including Cavalier King Charles Spaniels, Doberman Pinschers, and Boxers. Over the past several years however, heart disease, more commonly referred to as canine or feline dilated cardiomyopathy (DCM), has seen a sudden increase.
The taurine-DCM link
Back in the mid-1990s, veterinary cardiologists discovered a relationship between taurine deficiency and dogs with heart disease / DCM. Taurine is an amino acid that dogs absorb through food. These studies found some breeds were predisposed to taurine deficiency (Golden Retrievers and Cocker Spaniels), while others experienced it as a side-effect of eating certain types of diets.1
When reports of canine DCM began increasing recently, veterinary cardiologists once again suspected taurine levels. However this time, most of the dogs that were diagnosed did not have low taurine levels.2 Instead, a new pattern was emerging: dogs diagnosed with DCM were frequently on some form of boutique/ exotic ingredient/ grain-free (acronym BEG) diet, for anywhere from a few months to a few years. What made the reports even more unusual was the appearance of DCM in breeds of dogs not typically prone to the disease.
A closer look at the impact of BEG diets
Were the potatoes, peas, and legumes used in these grain-free foods causing some other form of deficiency? Was there an unidentified ingredient in BEG diets that was having a negative impact on heart function?
In July 2018, the FDA announced an investigation into increasing reports of canine DCM. Their initial findings showed that the cases reported to the FDA commonly had “diets (that) frequently list potatoes or multiple legumes such as peas, lentils, other “pulses” (seeds of legumes), and their protein […] early in the ingredient list, indicating that they are main ingredients,” however it was “not yet known how these ingredients are linked to cases of DCM.”3
One study by a veterinary cardiologist found that dogs with DCM that had been eating grain-free diets (heavy in peas, legumes and potatoes) had more advanced cardiomyopathic changes than did dogs with DCM that had been eating grain-based diets.4 Anecdotal reports from veterinarians indicated that some dogs improved after a diet change, however some of these were simply switched from one BEG diet to another, suggesting that DCM was not necessarily tied to the “grain-free” status of the diet.
In February of this year, the FDA released an updated investigation report, stating that “a large portion of the reported diets in DCM cases – both grain-free and grain-containing – contained peas and/or lentils in various forms (whole, flour, protein, etc.) as a main ingredient (listed within the first 10 ingredients, before vitamins and minerals).”5
Even though there appears to be a dietary correlation, there is still no definitive cause-and-effect relationship identified. “However, given the fact that we don’t yet understand why BEG diets are affecting some dogs, and because DCM is a life-threatening disease, I recommend you reconsider your dog’s diet until we know more,” says Lisa M. Freeman, DVM, PhD, DACVN at the Cummings Veterinary Medical Center at Tufts University.
Understanding heart disease in dogs
What are the early signs of heart disease?
Dogs in the early stages of DCM typically display symptoms of weakness, lethargy, moving more slowly, reluctance to exercise, shortness of breath, coughing, or fainting. However recent DCM reports include dogs “suddenly failing” without any of these signs, again possibly due to the correlation with BEG diets.
How is heart disease diagnosed?
If you notice any of the above symptoms, schedule a visit with your veterinarian or a veterinary cardiologist. Compile a list of everything your dog eats to help them determine a possible correlation between his diet and symptoms. (If diet does appear to be playing a factor, encourage your vet to report this information to the FDA to help identify and solve this problem.)
He or she will use a stethoscope to listen for abnormal heart rhythm or a heart murmur (be aware: not all changes due to DCM can be heard with a stethoscope). Your vet may draw blood to test taurine levels and other health factors.
Additional tests may include x-rays, an electrocardiogram, and a heart ultrasound (also known as an echocardiogram – which is the most definitive way to diagnose DCM).
How is heart disease addressed?
Depending on the results of your dog’s blood tests, your veterinarian may prescribe taurine supplementation, and/or other heart medications.
If you’re currently feeding some form of BEG diet, your vet may recommend you change your dog’s diet to one with more standard ingredients. You may need to consult with a veterinary nutritionist if your dog has allergies or other unique dietary needs.
Tips for choosing the best food
Trying to choose the “best food” is confusing – there are so many different products available, and compelling marketing often takes advantage of the latest “feeding fad.”
However, there are steps you can take to find a better diet for your companion:
1. Seek AAFCO-approved brands
First and foremost, choose a food that is manufactured according to the Association of American Feed Control Officials (AAFCO) standards. If you don’t see this mentioned on the label of your dog’s food, keep looking.
2. Learn how to read labels, but don’t take them too literally
According to AAFCO, ingredients must be listed in descending order of weight. This means that ingredients listed at the top of an ingredient paragraph are present in the food in higher amounts by weight than items at the bottom. However, listing order does not always indicate actual volume, because the weight of each ingredient includes water weight.
Compare whole chicken, which is approximately 70% moisture, to chicken meal, which is less than 10% moisture. Chicken would be listed higher on the ingredient list than chicken meal, even if both ingredients were providing the same amount of actual chicken.
According to The Cummings School of Veterinary Medicine at Tufts University, the quality of ingredients used in pet foods, as well as the overall quality of the pet food, is tied more to the manufacturer’s standards and protocols, processing steps, and testing of the finished product.
3. Look for the NASC Quality Seal
If a pet food manufacturer also makes supplements, see if they’re a member of the National Animal Supplement Council (NASC). This organization provides strict guidelines for consistent manufacturing and production process controls, product quality assurance, labels that conform to guidelines established by NASC with input from FDA/CVM and AAFCO, responsible and nationally consistent advertising, and adverse event reporting. Although NASC does not oversee pet food, if the food is being manufactured in the same facility as the supplements, the facility likely has good manufacturing practices in place for both.
4. Refer to the WSAVA list
Last but not least, the World Small Animal Veterinary Association (WSAVA) provides a list of recommendations that a company should meet when manufacturing pet food, including AAFCO standards, factual labels, information about nutrition analysis, caloric content, manufacturing location, and whether they have a veterinary nutritionist on staff or on consult. Although WSAVA does not certify foods (you won’t find a WSAVA seal on the bag), these guidelines can be helpful in choosing your dog’s food manufacturer.
To stay up to date on the latest diet/ DCM investigation, visit website that are following this issue closely, including:
You can also join this DCM Facebook group, whose purpose is to provide information concerning Nutritionally-Mediated DCM among veterinarians, breeders, members of the PhD and DVM research community, nutritionists, food brand representatives, nutrient suppliers, and dog owners. Upon joining, look in the left sidebar for the “Units” tab, where you can find various educational units that include scientific papers and fact-based articles.