Diet-Associated Cardiac Disease in Dogs: Resources and Recommendations

By Rebecca L. Stepien DVM’87, MS, DACVIM (Cardiology)

Over the past few years, there has been growing concern in the veterinary cardiology community about what appears to be an increasing incidence of heart disease (specifically, dilated cardiomyopathy-type changes) noted in dogs on certain types of diets.

Some of the first cases were diagnosed in golden retrievers and some of those affected dogs had documented low concentrations of whole blood taurine. Taurine is an amino acid that is necessary for normal cardiac muscle function. It is typically produced by the dog from precursor substances in the diet (i.e. consuming taurine in the diet is not required in dogs).

Since the problem was originally reported, the FDA has issued three alerts regarding this issue:

1. FDA Investigating Potential Connection Between Diet and Cases of Canine Heart Disease (July 12, 2018)
2. FDA Provides Update on Investigation into Potential Connection Between Certain Diets and Cases of Canine Heart Disease (February 19, 2019)
3. FDA Provides Third Status Report on Investigation into Potential Connection Between Certain Diets and Cases of Canine Heart Disease (June 27, 2019)

It is important to note that most dogs with diet-associated dilated cardiomyopathy do not have low taurine concentrations, so taurine consumption or metabolism does not appear to be the whole story. Veterinary nutritionists emphasize that other factors associated with grain-free diets, such as the use of unusual protein sources, use of legumes and potatoes as primary ingredients, and unknown sourcing, production, clinical testing and ingredient standards in smaller, local or “boutique” manufacturing processes, may be contributing to the problem. It is important to note that diets labeled as meeting the minimum requirements for nutrient levels set forth by the Association of American Feed Control Officials (AAFCO) may still put dogs at risk.

Research efforts are currently ongoing regarding the many questions associated with these clinical observations. Much remains unknown at this time, but there are steps that pet owners can take if their dogs have been consuming grain-free diets. Raw, vegetarian and home-cooked diets may also be of concern.

Steps to consider for dogs suspected of having or who have been diagnosed with dilated cardiomyopathy (DCM):

1. Be sure that your veterinarian is aware of what diet you are feeding your dog and why.
2. If your dog is showing signs of dilated cardiomyopathy (difficulty breathing, cough, irregular heart rhythms, fainting, fluid in the abdominal cavity), your veterinarian may recommend X-rays, an ECG (electrocardiogram) and an echocardiogram (cardiac ultrasound) to diagnose the disease and plan therapy.
3. If your dog is suspected of having or is diagnosed with dilated cardiomyopathy (DCM) and is eating a grain-free, vegetarian, vegan, or home-prepared diet, we recommend that you request that your dog’s veterinarian measure plasma and whole blood taurine concentrations through the Amino Acid Laboratory at the University of California, Davis (submission information can be found on the lab website).
4. If your dog has DCM, other dogs in the household eating the same diet should be screened for DCM (and taurine status, if DCM is found).
5. If possible diet-associated DCM is diagnosed, we recommend changing the diet to one made by a well-established manufacturer that contains standard ingredients (e.g. chicken, beef, rice, corn, and wheat). All dogs in the household eating the same grain-free diet should have their diet changed. If your dog has medical conditions that require a special diet, further consultation with your veterinarian and, possibly, a veterinary nutritionist, is recommended.
6. Dogs found to have low blood taurine should receive supplementation of taurine, regardless of any diet changes that may be made. Dogs with DCM that have low taurine concentrations may have improvements in cardiac function with supplementation over time, but because improvement may take months, dogs with severe clinical signs of DCM (difficulty breathing, cough, irregular heart rhythms, fainting, fluid in the abdominal cavity) will need cardiac medications to stabilize their clinical signs.
7. Dogs with DCM that have normal taurine concentrations may recover with diet change alone.

Steps to consider if your dog is apparently healthy and eating a boutique, exotic, grain-free, home-cooked, vegetarian or raw diet:

1. Be sure that your veterinarian is aware of what diet you are feeding your dog and why.
2. If you are interested in screening your dog for sub-clinical changes, ask your veterinarian to submit an NT-proBNP assessment (NT-proBNP is a cardiac biomarker that is assessed with a blood sample and is typically elevated when cardiac disease is present). If your dog’s NT-proBNP concentration is abnormal, an echocardiogram and plasma and whole blood taurine concentration is recommended.
3. Diet change is recommended for outwardly healthy dogs found to have dilated cardiomyopathy -like changes on screening echocardiography.
4. Taurine supplementation is recommended in addition to diet change in dogs with low taurine concentration, echocardiographic changes or both.
5. If problems are identified in one dog, other dogs in the household may benefit from screening and diet change.

An important take-home point is that the association between these types of diets and heart disease in dogs is not yet well understood and much research is occurring daily across the country. These recommendations may change over time. Interested dog owners should follow news reports closely and consult with their veterinarians, as well as their nearest veterinary cardiologist, regarding new developments.

In addition to the FDA links listed above, the website Taurine+DCM is strongly recommended for both dog owners and veterinarians. The site contains information, frequently asked questions and downloadable documents written by nutritionists, cardiologists and the FDA. There is also information for veterinarians on how to assess taurine using the Amino Acids Laboratory at UC Davis.

If you have further questions or would like to have your dog assessed for evidence of dilated cardiomyopathy, please contact the UW Veterinary Care Cardiology Service at 608-263-7600 or cardiology@vetmed.wisc.edu.

Additional resources:

1. Petfoodology, a website from the Cummings Veterinary Medical Center’s Clinical Nutrition Service with fact-based information on all aspects of pet nutrition, including diet-associated DCM. Some of the relevant posts on diet-associated DCM include:

• A Broken Heart: Risk of Heart Disease in Boutique or Grain-Free Diets and Exotic Ingredients
• It’s Not Just Grain-Free: An Update on Diet-Associated Dilated Cardiomyopathy
• Diet-Associated Dilated Cardiomyopathy (DCM): Update
• Questions You Should be Asking About Your Pet’s Food

2. FDA Investigation into Potential Link between Certain Diets and Canine Dilated Cardiomyopathy (updated June 27, 2019; includes information on cases and diets reported, as well as FAQs)
3. World Small Animal Veterinary Association Nutrition Toolkit, including tools for pet owners such as Selecting the Best Food for your Pet and The Savvy Dog Owner’s Guide to Nutrition on the Internet
4. Cummings School of Veterinary Medicine’s HeartSmart website. This site was developed for owners of dogs and cats with heart disease and contains information on different types of heart disease, as well as diagnosis, treatment, and monitoring of pets with heart disease (including diet).