Grain Free Diets for Dogs: A Veterinary Nutritionist Discusses Diet-Associated Heart Disease
By Rachele Baker, DVM – On July 12, 2018, the U.S. Food and Drug Administration (FDA) issued a notification about their investigation into reports of Dilated Cardiomyopathy (DCM) in dogs eating certain dog foods containing peas, lentils, other legume seeds, or potatoes as main ingredients (labeled as grain free diets for dogs). There is concern that the increased incidence of DCM in dogs may be associated with grain free diets for dogs, “exotic ingredient” diets, or diets made by small boutique companies.
Dr. Lisa Freeman has published some excellent articles on the subject of grain free diets for dogs and diet-associated heart disease on the Tufts University PetFoodology blog and has been kind enough to allow me to share excerpts from her articles here. Dr. Lisa Freeman is a board-certified veterinary nutritionist and a professor at Cummings School of Veterinary Medicine at Tufts University.
A broken heart: Risk of heart disease
in boutique or grain free diets and exotic ingredients
by Lisa M. Freeman, DVM, PhD, DACVN
June 04, 2018
Heart disease is common in our companion animals, affecting 10-15% of all dogs, with even higher rates in Cavalier King Charles Spaniels, Doberman Pinschers, and Boxer dogs. A recent increase in heart disease in dogs eating certain types of diets may shed light on the role of diet in causing heart disease.
In my twenty years as a veterinary nutritionist, I’ve seen vast improvements in our knowledge about pet nutrition, in the quality of commercial pet foods, and in our pets’ nutritional health. However, in the last few years I’ve seen more cases of nutritional deficiencies due to people feeding unconventional diets such as unbalanced home-prepared diets, raw diets, vegetarian diets, and boutique commercial pet foods.
The pet food industry is a competitive one, with more and more companies joining the market every year. Marketing is a powerful tool for selling pet foods and has initiated and expanded fads that are unsupported by nutritional science, including grain free diets for dogs and exotic ingredient diets. All this makes it difficult for pet owners to know what is truly the best food for their pet.
Dilated Cardiomyopathy (or DCM) is a serious disease of the heart muscle which causes the heart to beat more weakly and to enlarge. DCM can result in abnormal heart rhythms, congestive heart failure, or sudden death. In dogs, it typically occurs in large and giant breeds such as Doberman pinschers, Boxers, Irish Wolfhounds, and Great Danes, where it is thought to have a genetic component.
Recently, some veterinary cardiologists have been reporting increased rates of DCM in dogs in both the typical breeds and in breeds not usually associated with DCM such as Miniature Schnauzers or French Bulldogs. There is suspicion that the disease is associated with eating boutique or grain free diets for dogs with some of the dogs improving when their diets are changed. The US Food and Drug Administration (FDA) Center for Veterinary Medicine and veterinary cardiologists are currently investigating this issue.
Is diet the cause?
It’s not yet clear if diet is causing this issue. The first thought was a deficiency of an amino acid called taurine. Golden Retrievers and Cocker Spaniels were found to be at risk for DCM caused by taurine deficiency. And certain other breeds were found to be at increased risk for taurine deficiency and DCM including Newfoundlands, St. Bernards, English Setters, Irish Wolfhounds, and Portuguese Water Dogs.
The reasons for taurine deficiency in dogs are not completely understood but could be reduced production of taurine due to dietary deficiency or reduced bioavailability of taurine or its building blocks, increased losses of taurine in the feces, or altered metabolism of taurine in the body.
Recently some cardiologists noticed higher rates of DCM in Golden retrievers and in some atypical dog breeds. They also noticed that both the typical and atypical breeds were more likely to be eating boutique or grain free diets for dogs and diets with exotic ingredients – kangaroo, lentils, duck, pea, fava bean, buffalo, tapioca, salmon, lamb, barley, bison, venison, and chickpeas. Even some vegan diets have been associated. It has even been seen in dogs eating raw or home-prepared diets.
So, is this latest rash of DCM caused by taurine deficiency? Most of these affected dogs were eating boutique, grain free, or exotic ingredient diets. Some of the dogs had low taurine levels and improved with taurine supplementation. But even some of those dogs that were not taurine deficient improved with taurine supplementation and diet change.
It’s not so simple
Currently, it seems that there may be two separate problems occurring – one related to taurine deficiency and a separate and yet unknown problem (with a third group of dogs likely having DCM completely unrelated to diet). Identifying the potential dietary factors contributing to DCM in the non-taurine deficient dogs is more difficult, but the FDA and cardiologists are hard at work trying to solve it. What seems to be consistent is that it does appear to be more likely to occur in dogs eating boutique, grain free, or exotic ingredient diets.
There is no proof that grain free diets for dogs are better!
Many pet owners have, unfortunately, also bought into the grain free diets for dogs myth. The fact is that food allergies are very uncommon, so there’s no benefit of feeding pet foods containing exotic ingredients. And while grains have been accused on the internet of causing nearly every disease known to dogs, grains do not contribute to any health problems and are used in pet food as a nutritious source of protein, vitamins, and minerals.
Small pet food manufacturers might be better at marketing
than at nutrition and quality control
Making high quality, nutritious pet food is not easy! It’s more than using a bunch of tasty-sounding ingredients. The right nutrients in the right proportions have to be in the diet, the effects of processing (or not processing) the food need to be considered, and the effects of all the other ingredients in the food need to be addressed, in addition to ensuring rigorous quality control and extensive testing. Not every manufacturer can do this.
How could diet be increasing the risk for DCM?
What is the consistent factor between the diets being implicated in diet-related DCM? It may be related to companies’ inadequate nutritional expertise or rigorous quality control. However, these problems could also be related to problems with bioavailability or interaction with other ingredients in the diet (especially the more exotic ingredients, which are not as well studied or understood). And DCM could even be the result of an ingredient in the diet that is toxic to the heart.
What should you do?
If you’re feeding a boutique, grain free, or exotic ingredient diet, I would reassess whether you could change to a diet with more typical ingredients made by a company with a long track record of producing good quality diets. And be careful about currently available pet food rating websites that rank pet foods either on opinion or based on myths and subjective information.
It’s important to use more objective criteria (i.e. research, nutritional expertise, quality control) in judging a pet food. The best way to select what is really the best food for your pet is to ensure the manufacturer has excellent nutritional expertise and rigorous quality control standards (see “Questions you should be asking about your pet’s food”).
If you’re feeding your dog a boutique, grain free, or exotic ingredient diet, watch for early signs of heart disease – weakness, slowing down, less able to exercise, shortness of breath, coughing, or fainting. Your veterinarian will listen for a heart murmur or abnormal heart rhythm and may do additional tests (or send you to see a veterinary cardiologist) such as x-rays, blood tests, electrocardiogram, or ultrasound of the heart (echocardiogram).
If your dog is diagnosed with DCM and eating one of these diets, I’d recommend the following steps:
Ask your veterinarian to test taurine levels.
Report it to the FDA. Reporting it will help us to identify and solve this current problem.
Change your dog’s diet to one made by a well-known reputable company and containing standard ingredients (i.e. chicken, beef, rice, corn, wheat). Changing to a raw or homecooked diet will not protect your dog from this issue (and may increase the risk for other nutritional deficiencies). If your dog requires a homecooked diet or has other medical conditions that require special considerations, be sure to talk to a veterinarian or a veterinary nutritionist (acvn.org) before making a dietary change.
Any improvements in your dog’s DCM can take 3-6 months. Your dog will need regular monitoring and may require heart medications during this time. There’s no guarantee she’ll improve, but it is certainly worth a try.
It’s Not Just Grain Free:
An Update on Diet-Associated
By Lisa M. Freeman, DVM, PhD, DACVN
November 29, 2018
I’m pleased that people are interested in this important issue and trying to learn about it. But I’ve also found a tremendous amount of confusion and misinformation including people who doubt that this is a real issue, some who still haven’t heard about it, and people who mistakenly think it’s just grain free diets for dogs or that it’s only related to taurine. To clear up confusion, I thought I’d provide some updates to address the most common misconceptions I’m hearing.
It’s not just grain free diets for dogs
This does not appear to be just an issue with grain free diets for dogs. I am calling the suspected diets “BEG” diets – Boutique companies, Exotic ingredients, or Grain free diets for dogs. The apparent link between BEG diets and DCM may be due to ingredients used to replace grains in grain free diets for dogs, such as lentils or chickpeas, but also may be due to other common 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.
Most dogs being diagnosed with DCM do not have low taurine levels
Some owners continue to feed a BEG diet but supplement taurine thinking that this will reduce their risk for heart disease. In our hospital, we currently measure taurine in all dogs with DCM, but more than 90% of our patients with DCM in which taurine has been measured have normal levels (and the majority are eating BEG diets).
Yet some of these dogs with DCM and normal taurine levels improve when their diets are changed. This suggests that there’s something else playing a role in most cases – either a deficiency of a different nutrient or even a toxicity that may be associated with BEG diets. Giving taurine is unlikely to prevent DCM unless your dog has taurine deficiency. 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.
Raw diets and homemade diets are not safe alternatives
Out of concern, some owners are switching from BEG diets to a raw or home-cooked diet. However, we have diagnosed DCM in dogs eating these diets too. And raw and home-cooked diets increase your dog’s risk for many other health problems. So, forego the raw or home-cooked diets and stick with a commercial pet food made by a well-established manufacturer that contains common ingredients, including grains.
Current thoughts on DCM
Currently, it appears that there may be three separate groups of dogs with DCM (although this may change as we learn more). I am listing them in the approximate frequency that we are currently seeing them in our hospital:
Diet-associated DCM with normal taurine levels. While this form of the disease was first identified in dogs of breeds not predisposed to DCM that are eating BEG diets, it appears to also occur in dogs of typical DCM breeds that are eating a BEG diet.
Primary DCM in predisposed breeds that is unrelated to diet. This is the traditional, genetically-related DCM in typical breeds such as the Doberman Pinscher, Boxer, Irish Wolfhound, and Great Dane.
Diet-associated DCM with taurine deficiency: This is the least common form we are seeing in our hospital. This appears to happen both in breeds predisposed to DCM and breeds that are not predisposed to DCM.
What’s causing diet-associated DCM in dogs?
For the vast majority of dogs, we do not yet know what is causing this disease. There are definitely some dogs with DCM that have low taurine levels, many of which will improve with taurine supplementation and change of diet. For dogs that have normal taurine levels however, other nutritional deficiencies may be present. Some nutritional deficiencies can affect the heart’s normal function, so an insufficient amount of these nutrients (or reduced bioavailability) in the diet could cause heart disease. Diet-associated DCM could also be due to an ingredient in the food that is toxic to the heart.
My dog was diagnosed with DCM. What should I do?
Ask your veterinarian to measure taurine levels. Give heart medications as directed by your veterinarian. If your dog is eating a BEG diet or other unconventional diet (including vegetarian, vegan, or home-prepared diets), I recommend following the steps outlined in my previous post, including switching to a non-BEG diet. Three updates to my previous post are:
Taurine supplements: ConsumerLab released a report on independent quality control testing of taurine supplements in late 2018. Given the lack of quality control for dietary supplements (human and pet), having these results will be very useful to find good quality products for dogs that require taurine supplementation. Your veterinarian or veterinary cardiologist can help you determine an optimal dose for your dog.
Other dogs in the household: We are now recommending that other dogs in the household of dogs with DCM that are eating the same BEG diet be screened by their veterinarian since their hearts could also be affected (even if they are showing no symptoms).
Outcome: Not all dogs with DCM will improve, and improvements in the echocardiogram, when they do occur, can take a long time (often more than 6 months).
If my dog is eating a BEG diet but has no symptoms,
should I test for DCM or switch to a different diet?
It’s unlikely that most dogs eating a BEG diet will develop DCM. 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. Contrary to popular belief, there are no health benefits of grain free diets for dogs or exotic ingredient diets except in the rare case of food allergy.
Be sure to watch for early signs of heart disease – weakness, slowing down, less able to exercise, shortness of breath, coughing, or fainting. If you notice any of these, get your dog checked out by your veterinarian.
My hope is that this serious situation will shine a light on the complexities of making safe and nutritious pet food and the importance of nutritional expertise and quality control, rather than just what is new and trendy.
For more information on choosing the best food for your dog, please see my article titled The Best Nutrition For Dogs and Puppies: Choosing The Best Dog Food For Your Dog.