Grain-Free Diets & Heart Disease Update
Nicci Decrisantis
NorthPoint Pets & Company
May 2019 – updated June 2019*
Before discussing the FDA investigation into a potential association between heart disease and grain-free foods it is important to put this issue into perspective:
Over half of American dogs are overweight1, diabetes rates are rising faster than we can measure and cancer is becoming more prevalent not just in the old, but in the young2. Also common are kidney disease3 and liver disease4 and dogs and cats experiencing more food and environmental sensitivities and allergies than we have ever seen5. Diet-mediated dilated cardiomyopathy (DCM) has affected a relatively small number of dogs to date, approximately 500 out of approximately 77 million dogs in the United States – as of the latest FDA report*. While this is certainly a concern that warrants further investigation in a timely manner, it is not by any means an epidemic.
In examining the whole picture, we know that dogs and cats are not “healthy” – a reality that most of us either ignore or don’t believe to be true. Common problems like skin conditions, “dog smell”, and GI problems are not and should not be considered healthy; even though we’ve become to accept them as normal. Some of the reasoning behind “common” problems is because our pets are subjected to many variables over many generations and the consequences of such have impacted the overall wellbeing and susceptibility of varying types of disease. These variables include, but are not limited to: toxins and pollution in the air, water, soil and food supply, overuse of antibiotics and other medication, overvaccination, poor quality diet, poor breeding practices, poor nutrition, lack of exercise and radiation.
The good news is that just because an individual is “predisposed” to a particular disease does not mean that they are going to “get” that disease7 as the expression of these “bad genes” can be altered by a healthful diet and limiting exposure to toxins. – Alternatively, if dogs or cats are constantly exposed to various toxins, fed a diet lacking vital nutrition, moisture and meat protein, over-vaccinated, overmedicated and deprived of exercise and are obese much like how they have been for generations–they have a significant risk of developing the disease to which they are predisposed to. This new field of science, referred to as nutrigenomics, studies the nutrient impact on gene expression and nutritional influences on the Genome, Transcriptome, Proteome, and Metabolome and extract useful biological information on the data collected. This field has melded practices from Nutrition, Biology, Medicine, Genomics, and Bioinformation8.
Let’s imagine for a second that an individual was predisposed to heart disease, but they took care of themselves by consuming a diet rich in fresh foods, moderate fat, and sodium, avoided excess use of vaccinations, limited unnecessary medications, consumed clean water and exercised to maintain strong cardiac function – they would have a lesser chance of developing heart disease. For the sake of not oversimplifying this concept – a healthy lifestyle for us or our pets does not eliminate the risk of disease, but it does make our genes more resilient, or resistant to letting that disease develop or advance. In 2005, the Broad Institute began mapping the canine genome, which allows us to further explore what genetic markers are related to specific diseases. This mapping project will not only help us to identify targeted pharmaceutical and nutritional therapies that may help in treatment for prevention but also help to advance knowledge, treatment, and prevention of diseases for humans9.
Back in July of 2018 the FDA announced an investigation into grain-free dog foods potentially having a link to heart disease in dogs10. Specifically – Dilated Cardiomyopathy (DCM) which is a condition where the heart becomes enlarged and is unable to adequately pump blood. As a result, this condition can ultimately lead to heart failure. This disease is known to occur in dogs and cats, at varying levels of severity and has more than one cause11. Further complicating matters DCM has causation that is likely multivariable such as genetics, environmental, nutritional, infections, dysbiosis, and even other unknown causes11,12. Further commentary articles, not research articles, from experts examining the issue seemed to state that there is no direct evidence showing causation between DCM and grain-free pet foods – and that it will take several years to determine what the issue or issues are. It is important to note – out of some dogs diagnosed with DCM, some improved after a diet change from one grain-free diet to another, and this finding, along with the differences identified between dogs fed various grain-free diets, suggested that DCM was not necessarily tied to the grain-free status of the diet13. In addition, many dogs diagnosed with DCM were initially thought to be taurine-deficient, instead, most whole blood and plasma taurine testing revealed that most dogs were within normal limits.
DCM is not a ‘new’ concern for dogs or cats, in fact, it has been around for a long time. In the 1970’s -1980’s DCM was prevalent in cats and it was eventually determined that this was due to low concentrations of taurine and animal protein within the commercialized foods14. Pet food companies responded by adding taurine through supplementation and additional meat protein which has since remedied the issue6. However, since dogs and cats are nutritionally different it is unlikely that adding taurine to any diet will be sufficient to solve the problem in dogs, especially since this issue is likely far more complex. Further complicating matters, the only definitive diagnosis for DCM is an echocardiogram, although 24-hour Holter monitoring for predisposed breeds can be very suggestive in most cases. Other methods of screening for potential cardiac disease are whole blood taurine, plasma taurine, auscultation, and chest x-ray it is important to understand that these methods are not reliable in the diagnosis of DCM.
We know that certain breeds are genetically predisposed to DCM and those include (but are not limited to) Doberman Pinschers, Boxers, Great Danes, Labrador Retrievers, St. Bernards, Irish Wolfhounds, Golden Retrievers, Newfoundlands, English, and American Cocker Spaniels14,15. There is no cure for genetic DCM, and conventional veterinary treatment involves the use of diuretics, ACE inhibitors, antiarrhythmic, and other pharmaceutical agents to reduce stress on the cardiopulmonary system and kidneys to allow the body to tolerate the condition. Unfortunately, these options provide limited relief for a generally short period of time16.
DCM can also be closely related to diet – meaning that an individual’s susceptibility can be influenced by diet imbalance. Initially, the assumption with current DCM concerns was a lack of taurine in the diet for varying reasons. However, it was determined that this was likely not true for most cases and instead researchers are now considering a metabolic disorder preventing the body from utilizing taurine – while also keeping in mind that the issue may be something else entirely. Another theory is that one or more ingredients are interacting with others causing a blocking effect on taurine utilization. The truth is that researchers are unsure exactly what the mechanism behind this condition is6. Furthermore – there is no published, peer-reviewed research detailing any findings on this topic as of the date of this article.
In regards to the current issue; unfairly termed diet-mediated taurine deficient dilated cardiomyopathy – there are dogs that have been diagnosed with DCM who have been eating everything from grain-free, to grain-inclusive and even some homemade raw foods. Unlike cats, dogs are able to synthesize their own taurine from cysteine and methionine – which is why dogs eating diets high in grain or low in meat are generally not taurine deficient. While I am not in the position to publicly discuss brands at this time – some trends that have been noticed by those investigating the industry are as follows:
Dry foods that have a high carbohydrate content (grain or grain-free) which can be a problem for two reasons:
- This can result in an inadequate amount of meat protein which may lead to an imbalance or not enough of various nutrients – in this case, there may not be enough taurine which is what is responsible for helping the heart to beat correctly. Too little taurine (taurine deficiency) can result in DCM.
- Some plant-based proteins can cause malabsorption and inflammatory conditions in humans17. While insufficient research is available to suggest the same in pets, it is certainly a reasonable theory to explore. More and more institutions are exploring the similarities in humans and canines9,18–20 – and while some still refute the similarities, the stark similarities in types and rates of disease are unquestionable. Logically, these similarities are not surprising considering that by and large humans eat a highly-processed diet full of chemicals, lack exercise, overuse medication, and live exposed to environmental toxins and pollutions – just like their pets.
Some experts are recommending adding taurine to pets’ diets regardless of what you feed6 – which is sound advice. Adding taurine can be as simple as purchasing a taurine supplement from a trusted source. In addition, since taurine naturally occurs in animal products – not grains – adding items like chicken breast, beef or other animal heart, sardines, raw goat milk, and other animal products may be beneficial. Some grains do contain precursors to taurine – amino acids cysteine and methionine. Dogs can manufacture taurine from these amino acids. Cats are unable to manufacture their own taurine which is why the solutions are more complicated than they may seem.
Grains within pet food are not the problem per se. Most dogs are able to consume quality grains their entire lives without incident. Absent from the discussion on grain-free vs. grain inclusive diets for people – and pets – is the contamination of grains with herbicides, pesticides, mycotoxins, and fertilizers. There are numerous peer-reviewed articles detailing the disruption many of these contaminants have on normal gut bacteria function21,22. We’re learning that disruption of vital gut bacteria balance can have devastating effects on the health of the host23,24. This very contamination is likely why many pets experienced improvement of various symptoms with the change from grain- inclusive to grain-free.
Pet food can be made of everything from rendered unfit foods for human consumption to ingredients that are 100% organic and probably better than the food we feed ourselves. I’m not necessarily here to split hairs on ingredients and in the types of ingredients that are in our pet’s food. Because is it these ingredients that are causing the problem? Or is it something else? – These are the questions that the experts seem to avoid entirely. When a dog experiences issues related to food we are quick as a society to turn over the bag and blame an ingredient or set of ingredients. However, those ingredients as listed are likely not the problem – rather the quality, processing, and contamination of these ingredients; something you will never find listed on a label.
Kibble is heated to high temps which creates a chemical change. A Maillard Reaction Product (MRP) is a name for a series of reactions that is the product of sugar (or carbohydrate) and protein when heated. These are also known as AGE’s or Advanced Glycated End Products. MRP’s responsible for nutrient loss and associated with diseases like diabetes25, cardiovascular disease25,26, kidney disease26, loss of cognitive function26,27, allergies28, periodontal disease29, and chronic inflammation30 – this can mean things like arthritis, skin and ear issues, an old injury that keeps resurfacing, bloating, IBS, etc. In addition, there is a large amount of research to suggest that they are carcinogenic and accelerate aging30,31.
Heterocyclic amines are MRPs from cooking protein that increases with elevated cooking temperature, and this phenomenon is more pronounced in meat than fish – and these increase with temperature and dryness of meat or meat products32.
Acrylamides are a chemical that forms naturally from starchy foods during high-temperature cooking. According to the European Food Safety Authority evidence from animal studies shows that acrylamides are genotoxic and carcinogenic: they damage DNA and cause cancer. And since we know so little about animal nutrition is it possible that much of the disease we’re seeing – including DCM has at least something to do with the MRP’s that are in pet food?
Protein, fat, and carbohydrates go through irreversible denaturation with the heating process of making kibble. This very process can be responsible for a dog’s inability to tolerate certain foods in processed form, and for the incidence of certain diseases – but be able to tolerate and even thrive on fresh foods. We do not have enough research that fully explains what happens to food when it is processed beyond a recognizable state. Nor do we have enough epidemiological studies to understand the consequences of feeding processed food diets for generations. Unfortunately, what we do know is that DCM is not the only problem that will arise as a consequence of feeding a highly-processed diet – there will be more potentially more severe and prevalent conditions that will arise.
Please recognize that this does not mean that you must feed all fresh food – or all kibble. Theory always suggested that mixing fresh food and kibble would result in GI distress or cause problems over time. Fortunately, that theory no longer holds much weight. Rather, feeding vegetables and fruit that are high in antioxidants with kibble provide protective effects against MRP’s. In addition, feeding raw or cooked meat along with kibble provides amino acids, vitamins, and minerals in their most natural form. While research is in the works and isn’t yet published, researchers are finding that feeding raw and kibble together actually reduced inflammatory markers for certain diseases, when done properly. There is also a notable but non-peer reviewed case-study of a dog successfully fed fresh food and kibble which suggested that kibble may have digested at the same rate or slightly faster than raw33.
Regardless of what method you choose to feed – feeding fresh food does not only mean raw or cooked meat. Fresh food such as vegetables and fruit can provide some antioxidant protection against MRP’s, provide additional phytonutrients in their most natural form and improve digestive function. In addition, consumption of green, yellow and cruciferous vegetables reduces oxidative stress which can lead to lower incidence of certain cancers, cardiovascular disease, promote liver detoxification, reduce inflammation and positively impact the function of the immune system34.
Keeping in mind that every animal is different, and that not any one diet or food is right for every animal – no feeding regimen will be successful for all pets. All diet changes and additions should always be introduced slowly and carefully. It is always helpful to keep a food journal that can help experts determine potential foods or feeding patterns that may be problematic.
*This article was updated as of June 2019 to reflect updated information per the latest FDA report: https://www.fda.gov/animal-veterinary/news-events/fda-investigation-potential-link-between-certain-diets-and-canine-dilated-cardiomyopathy
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33. Digest this: kibble may actually digest faster than raw. The Raw Feeding Community. https://therawfeedingcommunity.com/2015/01/08/digest-this-kibble-may-actually-digest-faster-than-raw/. Published January 9, 2015. Accessed May 15, 2019.
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