Understanding Canine Heart Conditions and Grain-Free Diets
In recent years, grain-free diets for dogs have gained immense popularity, leading to discussions among pet owners and veterinarians about their safety and implications. While these diets may be appealing for those wishing to avoid allergens, there are growing concerns about a potential connection between grain-free nutrition and Canine Dilated Cardiomyopathy (DCM). Let’s explore some of the facts and research and what they mean for dog owners.
What is Canine Dilated Cardiomyopathy (DCM)?
DCM is a serious heart ailment marked by an enlarged heart and a diminished ability to pump blood efficiently. In severe instances, it can result in congestive heart failure and even death. Traditionally, breeds such as Doberman Pinschers and Boxers have been more susceptible to this condition. However, there has been a rise in DCM cases among breeds that are not typically linked to this disorder.
Concerns About Grain-Free Diets
The FDA has initiated investigations into grain-free diets following a rise in reported DCM cases. Many of these diets are rich in ingredients like peas, lentils, and other legumes, rather than conventional grains. The concern is that these diets could lead to taurine deficiencies, an essential amino acid vital for maintaining heart health. Research has associated taurine deficiency with DCM, suggesting that dogs on certain grain-free diets may have insufficient levels of this amino acid.
Research Insights
While early studies raised alarms about the risks associated with grain-free diets, experts suggest that the connection between these diets and DCM is complex. Here are some important findings from recent research:
Nutritional Deficiency: Research indicates a correlation between certain grain-free diets and taurine deficiencies. Dogs consuming specific “boutique” grain-free diets have been found to struggle in maintaining adequate taurine levels. However, a new study from the University of Guelph in Ontario, Canada, suggests that ingredients like lentils, beans, and field peas, commonly found in grain-free dog foods, are safe for healthy dogs. This is encouraging news for dog owners concerned about the rising popularity of grain-free diets, which now represent nearly half of the dog food market in many places.
A study published in The Journal of Nutrition found that dogs fed diets containing up to 45% whole pulse ingredients and no grains over a 20-week period showed no signs of heart problems. Additionally, the dogs’ body composition changed by less than 0.1% from baseline, regardless of the diet, indicating they maintained their lean body mass.
“This study is the longest controlled feeding study to date evaluating cardiometabolic health in healthy adult dogs on pulse-inclusive diets,” stated Dr. Kate Shoveller, the lead author and a professor in the Department of Animal Biosciences at the Ontario Agricultural College, as well as the Champion Petfoods Chair in Canine and Feline Nutrition, Physiology, and Metabolism.
Dr. Adronie Verbrugghe, a professor of clinical studies and the Royal Canine Veterinary Diets Endowed Chair in Canine and Feline Clinical Nutrition at the Ontario Veterinary College (OVC), stated, “This research is crucial for helping veterinarians provide evidence-based dietary recommendations for their patients. While some dogs may be healthy, others may have specific health issues that require targeted protein sources and content.”
Pulses as a Reliable Protein Option in Pet Food
PhD student Pawanpreet Singh is involved in studying dogs for this research. Pulses represent a valuable protein source in pet food and should be included in plant-based formulations to ensure adequate dietary protein levels. However, there have been concerns that pulses may lack essential amino acids necessary for synthesizing taurine, which is vital for heart health. Additionally, the poor bioavailability of these key amino acids has been associated with insufficient protein absorption and muscle wasting in dogs.
To examine the potential impact of pulse ingredients on the cardiac health of healthy dogs, researchers conducted a randomized, controlled trial with 28 Siberian huskies. These dogs are not genetically predisposed to dilated cardiomyopathy (DCM), ensuring any observed changes in heart health would be attributed to diet rather than genetics. Each dog was assigned to one of four diets containing varying percentages (0%, 15%, 30%, or 45%) of whole pulse ingredients, including green and yellow peas, pinto beans, chickpeas, and lentils, while all diets included chicken as the animal protein source and were balanced in protein and fat content.
Lead author Pawanpreet Singh, a PhD student in animal biosciences at the University of Guelph, noted that the pulse ingredient concentrations mirrored those found in commercial dog food formulas. “We aimed to keep all diet aspects consistent except for the pulse ingredient amounts so that any changes in cardiac function could be linked to the varying pulse levels rather than nutrient intake,” said Singh.
No Changes in Body Composition or Cardiac Function
The study was funded by Champion Petfoods, although the company did not influence the outcomes or interpretations of the research. Veterinary cardiologist Dr. Shari Raheb, a professor in OVC’s Department of Clinical Studies, conducted echocardiograms to monitor heart changes, while Singh regularly collected blood samples to evaluate cardiac biomarkers and amino acid levels. Verbrugghe and registered veterinary technician Shoshana Verton-Shaw assessed body composition at both the start and conclusion of the study, with weekly weight checks for all dogs.
“We took extensive precautions to monitor the health of these dogs, conducting monthly health evaluations and checking their heart blood markers to ensure there were no indications of cardiac stress,” Singh explained. “Our findings revealed that no matter the amount of pulses consumed, the dogs did not exhibit changes suggesting the onset of DCM or alterations in body composition.”
Shoveller noted that earlier clinical studies had failed to determine whether pulse ingredients contributed to DCM in dogs not genetically at risk. “Our data indicate that including pulse ingredients in dog food is not a causative factor and highlight the need to understand the nutrient composition of each ingredient while ensuring that foods meet or exceed minimum nutrient standards,” she said. “Ultimately, pulses are a reliable protein alternative in the food industry, and this study underscores their safety, even when used in high concentrations.”
Are Grain-Free Dog Foods the Actual Cause of DCM?
The exact cause of dilated cardiomyopathy (DCM) in dogs remains unclear, but researchers have made notable strides in understanding the issue. Initially, grain-free diets were singled out as potential culprits; however, further research has shown that some grain-free diets do not appear to have negative effects. More commonly, the dogs diagnosed with DCM have been consuming commercial grain-free diets containing pulses, which include plants like peas, lentils, chickpeas, and dry beans. Interestingly, soybeans, a prevalent ingredient in dog food, have not been linked to diet-related DCM. Among the pulses, peas have been most frequently associated with DCM, possibly due to their widespread use in grain-free formulations. While potatoes and sweet potatoes may also play a role, they were included in fewer of the assessed grain-free diets. These pulses and potatoes are typically used to replace grains in these diets.
It’s important to note that peas, pulses, and potatoes are not inherently harmful to dogs. In many cases, it can take over a year of consuming these diets—where pulses replace traditional grain-based meals—before any signs of diet-related DCM appear. However, one study indicated that dogs on a predominantly pea-based diet exhibited enlargement of the left ventricle of the heart after just three months, although
these changes may fall within normal variations. Such alterations can occur long before any heart failure symptoms manifest, suggesting there may be more affected dogs than currently reported.
Recent Studies on DCM in Dogs
In 2023, two studies yielded seemingly conflicting results regarding DCM. The first study observed that transitioning 91 dogs (including breeds such as American Staffordshire Terriers, Staffordshire Bull Terriers, and American Bulldogs—all not typically associated with hereditary DCM) from nontraditional diets (primarily comprising pulses and potatoes) to traditional diets improved their survival rates. This finding supports the notion that pulses and potatoes may be central to the DCM issue.
Conversely, the second study mentioned above in this article, funded by Champion Pet Foods, suggested that these pulses might not be the cause. However, this study only monitored dogs for a 20-week period, whereas research indicates that it typically takes about four years for dogs on grain-free diets to develop DCM. The researchers found that Siberian Huskies fed diets with up to 45% whole pulse ingredients and no grains exhibited no signs of DCM-related heart issues during the 20 weeks. This breed was chosen because it is not known for hereditary DCM, making it easier to attribute any DCM cases to diet. Currently, it remains unclear whether certain breeds are more susceptible to DCM related to their diet.
What About Ancient Grains?
The phrase “ancient grains” is somewhat of a marketing concept but typically refers to grains that have not undergone significant changes over the last few centuries. Unlike contemporary grains such as wheat, corn, and rice, these grains haven’t been hybridized or selectively bred for traits like increased yield or gluten content. Common examples include:
- Quinoa: A seed classified as a complete protein, it is abundant in fiber and antioxidants.
- Amaranth: This seed is also a complete protein and is high in iron and calcium.
- Spelt: A precursor to modern wheat, spelt has a lower gluten content compared to contemporary wheat.
- Kamut: An ancient wheat variety recognized for its distinctive nutty taste.
- Farro (Emmer): Another ancient grain related to wheat, farro is high in fiber and protein.
- Sorghum: A gluten-free cereal grain suitable for both human and animal consumption.
- Millet: These small, round grains are naturally free of gluten.
Potential Advantages of Ancient Grains for Dogs:
- Nutrient Density: Ancient grains often contain more protein, fiber, vitamins, and minerals than refined grains such as white rice or corn.
- High Fiber Levels: Fiber aids in digestion, helps regulate blood sugar, and can promote satiety, potentially assisting in weight management.
- Reduced Gluten (In Some Cases): Although not all ancient grains are gluten-free (like spelt, kamut, and farro, which do contain gluten), they may be more easily digestible for certain dogs with sensitivities compared to modern wheat. (Note: “gluten-free” does not equate to “grain-free.”)
- Diverse Nutritional Profile: Adding a variety of grains can provide a wider range of nutrients.
- Hypoallergenic Possibilities: For dogs with allergies, an unfamiliar ancient grain could serve as a suitable carbohydrate source. However, it’s essential to remember that food allergies are unique to each dog, and any grain has the potential to cause an allergic reaction.
Possible Disadvantages and Considerations:
- Not Necessarily Better: The label “ancient” does not guarantee superior health benefits. The nutritional value of grains varies, and some contemporary grains can be equally nutritious, according to some sources.
- Gluten Presence (In Some): Spelt, kamut, and farro contain gluten. These should be avoided if your dog has a confirmed gluten allergy or intolerance, although this is uncommon in dogs.
- Higher Cost: Dog foods containing ancient grains may come with a higher price tag compared to those with more commonly used grains.
- Carbohydrate Levels: All grains are primarily composed of carbohydrates. While dogs can digest carbohydrates, they should not dominate their diet; excessive carbs can lead to weight gain and other health issues.
- Allergy Risks: Although sometimes considered hypoallergenic, any ingredient can cause allergic reactions. Introduce new foods gradually and monitor for any signs of adverse reactions, such as itching, skin issues, or digestive disturbances.
- Skepticism Towards Marketing Claims: Be cautious of exaggerated health claims. Always review the complete ingredient list and nutritional information rather than focusing solely on the presence of “ancient grains.”
Who Might Benefit from an Ancient Grain Diet?
- Dogs with Sensitivities: If your dog is sensitive to common grains like corn or wheat, ancient grains may be a viable replacement, but it’s important to introduce them carefully and observe any reactions.
- Owners Looking for Variety: If you aim to diversify your dog’s diet and enhance nutrient intake.
Who Might NOT Benefit?
- Dogs with Gluten Allergies: Avoid spelt, kamut, and farro.
- Dogs Prone to Weight Issues: Be cautious of carbohydrate levels.
- Dogs with Other Specific Allergies: Keep in mind that any grain can potentially trigger allergic reactions.
- Dogs Doing Well on Their Current Diet: If your dog is thriving, there may be no need for a change.
Key Considerations Before Making a Switch:
- Consult Your Veterinarian: This step is vital. Your vet can evaluate your dog’s specific needs and health condition and suggest the most appropriate diet.
- Carefully Review Labels: Look closely at the entire ingredient list instead of just focusing on the advertised “ancient grains.”
- Gradual Transition: Slowly change your dog’s diet over a period of 7-10 days to reduce the risk of digestive upset.
And, most importantly:
***Monitor Your Dog’s Response: Pay attention to any changes in appetite, energy, digestion, skin health, or stool quality.***
We’d love to know what you think! Have you tried any specific diets for your dog, such as grain-free ones? This is a great topic to explore further in the forums. If you know a veterinarian or pet nutrition expert who would like to join us for a podcast, please reach out. Also, we encourage you to share your experiences in the comments below!
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