Grain-Free Diets & Heart Disease Update
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,
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
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
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
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
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
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
in pets | AAHA. https://www.aaha.org/pet_owner/lifestyle/obesity-in-pets.aspx.
Accessed May 15, 2019.
in Pets. https://www.avma.org/public/PetCare/Pages/Cancer-in-Pets.aspx.
Accessed May 15, 2019.
CE. Chapter 136 – Chronic Renal Failure. In: Silverstein DC, Hopper K, eds. Small
Animal Critical Care Medicine. Saint Louis: W.B. Saunders; 2009:594-598.
NH, Buxton RJ, Vicek TJ, et al. Breed, age and gender distribution of dogs with
chronic hepatitis in the United Kingdom. Vet J Lond Engl 1997.
R, De Benedetto A. Atopic Dermatitis in Animals and People: An Update and
Comparative Review. Vet Sci. 2017;4(3). doi:10.3390/vetsci4030037
add taurine to grain-free dog foods, say scientists | PetfoodIndustry.com.
Accessed May 15, 2019.
P. We are what we eat. The link between diet, evolution and non-genetic
inheritance. EMBO Rep. 2008;9(5):413-415. doi:10.1038/embor.2008.61
NMR, Pelegrini PB, Goersch MC. Nutrigenomics: Definitions and Advances of This
New Science. Journal of Nutrition and Metabolism. doi:10.1155/2014/202759
Disease Mapping Project (DogDNA). Broad Institute.
Published June 9, 2011. Accessed May 15, 2019.
C for V. FDA Investigating Potential Connection Between Diet and Cases of
Canine Heart Disease. FDA. February 2019.
Accessed May 15, 2019.
Dilated Cardiomyopathy (DCM). Cornell University College of Veterinary
Published December 13, 2017. Accessed May 15, 2019.
Cardiomyopathy in Dogs.
Accessed May 15, 2019.
LM, Stern JA, Fries R, Adin DB, Rush JE. Diet-associated dilated cardiomyopathy
in dogs: what do we know? J Am Vet Med Assoc. 2018;253(11):1390-1394.
PD, Kittleson MD, Thomas WP, Skiles ML, Rogers QR. Clinical findings in cats
with dilated cardiomyopathy and relationship of findings to taurine deficiency.
J Am Vet Med Assoc. 1992;201(2):267-274.
CDSBM. Breed-specific variations of cardiomyopathy in dogs. dvm360.com.
Accessed May 15, 2019.
Cardiomyopathy in Dogs. vca_corporate.
Accessed May 15, 2019.
DLJ. Do dietary lectins cause disease? BMJ. 1999;318(7190):1023-1024.
by DogRisk. University of Helsinki. https://www.helsinki.fi/en/researchgroups/dogrisk-health-via-nutrition-epidemiology-and-cancer-detection-dogs/research-by-dogrisk.
Published June 26, 2018. Accessed May 15, 2019.
companion dog as a model for human aging and mortality – Hoffman – 2018 – Aging
Cell – Wiley Online Library.
https://onlinelibrary.wiley.com/doi/full/10.1111/acel.12737. Accessed May 15,
J. A Surprising Way Dogs Are Similar to Humans. Smithsonian.
Accessed May 15, 2019.
Bruggen AHC, He MM, Shin K, et al. Environmental and health effects of the
herbicide glyphosate. Sci Total Environ. 2018;616-617:255-268.
Y, Ba-M’hamed S, Elhidar N, Nafis A, Soraa N, Bennis M. Glyphosate based-
herbicide exposure affects gut microbiota, anxiety and depression-like
behaviors in mice. Neurotoxicol Teratol. 2018;67:44-49.
AK, Low D, Mizoguchi A, Mizoguchi E. Current Understanding of Dysbiosis in
Disease in Human and Animal Models. Inflamm Bowel Dis.
L. The Gut Microbiome and the Brain. J Med Food. 2014;17(12):1261-1272.
K, Cooper ME. The Role of AGEs in Cardiovascular Disease.
M, SECARA I, ONOFRIESCU M, et al. Consequences of Advanced Glycation End
Products Accumulation in Chronic Kidney Disease and Clinical Usefulness of
Their Assessment Using a Non-invasive Technique – Skin Autofluorescence. Mædica.
27. West R,
Moshier E, Lubitz I, et al. Dietary advanced glycation end products are
associated with decline in memory in young elderly. Mech Ageing Dev.
PK, Masilamani M, Li X-M, Sampson HA. The false alarm hypothesis: Food allergy
is associated with high dietary advanced glycation end-products and
proglycating dietary sugars that mimic alarmins. J Allergy Clin Immunol.
glycation endproducts (AGEs) induce oxidant stress in the gingiva: a potential
mechanism underlying accelerated periodontal disease associated with diabetes –
Schmidt – 1996 – Journal of Periodontal Research – Wiley Online Library.
Accessed May 15, 2019.
C, Imrhan V, Marotta F, Juma S, Vijayagopal P. Lifestyle and Advanced Glycation
End Products (AGEs) Burden: Its Relevance to Healthy Aging. Aging Dis.
DP. Advanced glycation end-products: a biological consequence of lifestyle
contributing to cancer disparity. Cancer Res. 2015;75(10):1925-1929.
M, Skog K, Arvidsson P, Solyakov A. Chemistry, formation and occurrence of
genotoxic heterocyclic amines identified in model systems and cooked foods. Z
Für Leb -Forsch A. 1998;207(6):419-427. doi:10.1007/s002170050355
this: kibble may actually digest faster than raw. The Raw Feeding Community.
Published January 9, 2015. Accessed May 15, 2019.
and Nutraceuticals in Vegetables and Their Multi-dimensional Medicinal and
Health Benefits for Humans and Their Companion Animals: A Review – SciAlert
Responsive Version. doi:10.3923/jbs.2014.1.19