On June 27, 2019, the U.S. Food and Drug Administration (FDA) named 16 brands of dog food that may cause heart disease in dogs. The specific heart condition is called dilated cardiomyopathy (DCM). This release has caused national and international concern bordering upon hysteria, without any admitted good reason for listing these food brands. In our opinion, the listing of specific brands was premature and unwarranted.
Bear in mind, the FDA did not name a specific product(s) under its brand name, but an entire brand that was mentioned ten or more times by pet companion parents or veterinarians that submitted case reports of dogs diagnosed DCM. There was no scientific basis for this rationale, simply frequency. The listed products are most frequently of the so-called grain-free type.
The FDA’s investigation has been happening since 2014, but received nationwide attention after the agency’s first public notice in July, 2018.
This investigation has turned into a saga with multiple parties weighing in over the past year that is causing mass confusion to pet companion parents.
Hemopet and Dr. Dodds will attempt to break down the situation, present the FDA’s latest findings and provide our response.
The Nutritional Science
Taurine is an essential amino acid for dogs. At this time, taurine is not considered an essential food-sourced amino acid for dogs. Taurine is synthesized in the liver from the amino acids cysteine and methionine, which should provide sufficient quantities to meet dogs’ metabolic needs.
The Major Moments That Have Happened Thus Far
June 4, 2018
A veterinarian at Tufts University wrote an article and notified the FDA stating her belief that grain-free dog food can cause DCM in dogs.
July 12, 2018
The FDA issues an alert describing the potential link between grain-free diets and DCM in dogs. Veterinary cardiology and nutrition researchers from the veterinary schools at the University of California at Davis (UCD) and the University of Florida (UF) are also believed to have brought this concern to the attention of the FDA.
July 29, 2018
Dr. Dodds and Hemopet stated this sort of announcement was premature and pointed out other canine DCM studies that should be considered during the investigatory process. Since then, this article is Hemopet’s fifth commentary on the subject.
July 12, 2018-November 30, 2018
The veterinary cardiologist from the University of California Davis – who focuses on heart disease in Golden Retrievers – a breed he personally has — gave many interviews implicating grain-free diets as a cause of heart disease in dogs. The pet food industry and several veterinarians have pushed back.
December 1, 2018
An article from the above researchers titled, “Diet-associated dilated cardiomyopathy in dogs: what do we know?” appeared in the Journal of American Veterinary Medical Association (JAVMA).
The article referenced a retrospective study of 48 dogs diagnosed with DCM by the UF researcher. The JAVMA commentary stated, “Notably, however, some dogs improved after a diet change from one grain-free diet to another, and this finding, along with the differences identified between dogs fed various BEG diets (boutique, exotic-ingredient, and grain-free), suggested that DCM was not necessarily tied to the grain-free status of the diet.”
Another study – conducted by the UCD researcher – involved 24 golden retrievers with documented taurine deficiency and DCM was also referenced. Limitations to the study included a lack of standardization across all cases, so researchers could not clearly identify any treatment-specific differences from their results.
Ultimately, the authors of this JAVMA article speculate that “exotic” ingredients are causing the rise of DCM in dogs. They include kangaroo, duck, buffalo, salmon, rabbit, venison, lamb, bison, fava beans, peas, tapioca, barley, lentils, peas and chickpeas as example ingredients.
The authors write:
“The apparent link between BEG diets and DCM may be due to the grain-free nature of these diets (ie, use of ingredients such as lentils, chickpeas, or potatoes to replace grains), other common ingredients in BEG diets (eg, exotic meats, flaxseed, fruits, or probiotics), possible nutritional imbalances, or inadvertent inclusion of toxic dietary components. Or, the apparent association may be spurious.”
February 19, 2019
The FDA updated its findings of its ongoing research into the matter.
June 27, 2019
The FDA provided further updates on its ongoing research into DCM and replaced the February 19th posting with the June 27th findings.
Standouts from the FDA’s June 27, 2019 Report
This latest status report by the FDA is lengthy and has caused undue alarm among the public and veterinarians. We have summarized the statements and findings that stood out. If we directly quote the FDA, we will put its acronym after the statement.
- “Based on the data collected and analyzed thus far, the agency believes that the potential association between diet and DCM in dogs is a complex scientific issue that may involve multiple factors”. – FDA
- “For the purposes of this investigation, the FDA defines a “case” as an illness reported to FDA involving a dog or cat that includes a diagnosis of DCM”. – FDA
- “We did not include in these numbers the many general cardiac reports submitted to the FDA that did not have a DCM diagnosis. However, this case information is still valuable, as it may show heart changes that occur before a dog develops symptomatic DCM”. – FDA
- Between January 1, 2014 and April 30, 2019, the FDA received 524 reports of DCM (515 canine reports, 9 feline reports).
- DCM is recognized as a genetic condition with a nutritional component typical in larger breed dogs. However, the FDA received confirmed DCM diagnoses for small and medium size breeds.
- For this investigation, the FDA received a disproportionate amount of reports about Golden Retrievers (95) due to breed-specific social media groups and activities that have raised awareness of the issue, and encouraged owners and vets to submit reports to FDA.
- 452 reported dog food formulations were of dry (kibble).
- 90% of the products were labeled as grain-free.
- Of the grain-free category, 93% had peas or lentils, 89% contained peas, 62% had lentils, and 42% contained potatoes or sweet potatoes.
- “Animal protein sources in the reported diets varied widely, and many diets contained more than one protein source”. – FDA
- Per animal sources, chicken was identified 113 times; lamb, 98; salmon, 72; white fish, 65; kangaroo, 58; turkey, 57; beef, 47; pork, 24; venison, 21; duck, 20; bison, 20; egg, 18; vegetarian, 7; rabbit, 4; goat, 1.
- “Before the July 2018 DCM Update, FDA/Vet-LIRN had tested multiple products for minerals and metals (calcium, magnesium, phosphorus, iron, cobalt, copper, zinc, selenium, iodine) and amino acids including taurine, cysteine, and methionine. That product testing did not reveal any abnormalities”. – FDA
- “The average percent protein, fat, total taurine, total cystine, total methionine, total methionine-cystine, and resistant starch content on a dry matter basis (in other words, after removing all moisture content) were similar for both grain-free labeled and grain-containing products”. – FDA
- “Nearly all the grain-free products had methionine-cystine values above the minimum nutritional requirement of 0.65 percent for adult maintenance food for dogs published in the Association of American Feed Control Officials (AAFCO) Official Publication”. – FDA
- “Additional food testing is in progress”. – FDA
FDA Update on Vet-LIRN
Vet-LIRN is the FDA’s section geared to veterinarians and provides more technical information.
Diagnosis and Findings
The best way to diagnose DCM in dogs is by measuring taurine in the blood and with an echocardiogram. Oftentimes, DCM is diagnosed by taurine measurement alone with either whole blood, plasma or both.
Taurine status is based on reference ranges established by laboratories.
According to the FDA Vet-LIRN, 176 dogs diagnosed with DCM and without DCM had both tests run. Of those diagnosed with DCM:
- 51 dogs had low taurine status (either whole blood and/or plasma)
- 38 had normal taurine status
- 27 had high taurine status
The FDA is working with Chesapeake Veterinary Cardiology Associates (CVCA), which operates multiple clinics in the Mid-Atlantic region. Once DCM is diagnosed, CVCA will collect blood (whole blood and plasma), urine, feces, DNA swabs, and food, if the pet is not receiving any supplements (e.g. taurine, cystine, or methionine) and is still eating a diet labeled “grain-free.” They will repeat these tests at various intervals.
Vet-LIRN is also collecting food associated with each CVCA case and will test each diet for:
- protein, fat, moisture
- crude fiber, total dietary fiber, soluble fiber, insoluble fiber
- total starch, resistant starch
- free and total cystine, methionine, and taurine
The work with CVCA was mentioned in the public version of the report. The FDA elaborated on another separate investigation:
“Vet-LIRN has contracted with a network lab to collect blood (whole blood and plasma), urine, feces, and DNA from healthy dogs without a known breed predisposition to DCM for comparison. The dog must also be consuming a grain-containing primary diet that meets the following criteria:
- not be labelled “grain-free”
- consuming the diet for at least 1 year before the samples are collected
- animal proteins are from either cattle, swine, poultry, and/or fish
- no more than 2 legume, pulse, or potato (including sweet potato) ingredients that must appear after the animal and grain ingredients
- the diet formulation was verified to be nutritionally adequate by animal feeding tests using AAFCO procedures
The blood and urine samples will be tested similarly to those collected in the cases from CVCA collaboration and compared to the values from the dogs diagnosed with DCM. As of April 30, 2019, Vet-LIRN has collected samples from 11 healthy dogs. The results are being tested and evaluated.”
The Vet-LIRN page alluded to treatment, “According to recheck echocardiograms in the medical records, some pets with DCM improved after veterinary treatment (medications), diet change, and taurine supplementation, while others improved with appropriate veterinary care and diet change alone.”
Many pet companion parents would like us to give our thoughts as to the cause of DCM in dogs. We also have our speculations. Since so much speculation has already occurred without conclusions, we will not get involved at this point, as we do not want to lead anyone down the wrong path.
In essence, we agree with the FDA that the association between diet and DCM in dogs is a complex scientific issue that may involve multiple factors. However, we think the FDA is causing public panic and overt veterinary concern by not presenting definitive conclusions but implying risk by inference in listed certain pet food brands.
As companion pet parents, we are pleased the agency is taking a multi-pronged approach. But, we believe that premature biases have become ingrained (sorry — pun intended).
As taxpayers, we are pleased with the transparency. As companion pet parents, we find the report translucent – not transparent.
Indeed, so much conflicting or partial information is being tossed out there that we too are confused.
We note that this group of researchers is speculating on exotic ingredients like kangaroo, but chicken was the most common protein identified by the FDA – 113 times.
Plus, we know that some dogs are improving with veterinary treatment, taurine supplementation and diet change, OR veterinary treatment and diet change, OR even with no diet change. However, we are not receiving the specifics. The agency only mentions a couple of case studies in its latest report.
Again, the findings offer no scientific conclusion. The FDA clearly needs to continue to find out more information, but we urge that this agency only release conclusions and not premature commentary that can lead to confusion, panic, and decisions that are not best for the health of our pets.
The FDA admits that they received a bias with respect to information regarding Golden Retrievers diagnosed with DCM.
The FDA does not admit that the agency itself established any bias from the outset. On July 12, 2018, the agency pointed to grain-free diets as the possible culprit of DCM. This focus caused panic, so many of the pet companion parents feeding grain-free foods had their dogs tested. This led to a disproportionate amount of cases that were grain-free fed being reported when compared to dogs fed diets that were grain-containing.
Additionally, the FDA only requested reports of dogs that had DCM. So, if your companion dog was tested for DCM with both an echocardiogram and blood testing but did not have any heart condition, you or your veterinarian might not have submitted the report. Even though the FDA basically disregarded these reports, the agency did still collect and use them.
No matter what, if you have had your dog tested, we suggest submitting your companion dog’s results to the FDA – no matter what the results were.
Hemopet is pleased the FDA has dedicated resources to this issue. As we said, the multi-pronged approach still seems rather biased and segmented.
Remember that the Vet-LIRN has contracted with a network lab to collect blood (whole blood and plasma), urine, feces, and DNA from healthy dogs without a known breed predisposition to DCM for comparison. The dog must also be consuming a grain-containing primary diet.
Why is the agency not requesting the same laboratory work of healthy dogs without a known breed disposition for DCM that are eating grain-free diets? Thus far, this sample size seems relatively small and a control group is nonexistent.
Why is the agency not actively requesting laboratory work of dogs diagnosed with DCM, without a known breed disposition to DCM, and that were eating grain-containing diets at the time of diagnosis?
Will more than one laboratory be analyzing the whole blood and plasma taurine levels ? Will the diet of these analyzed samples be double-blinded until after the laboratory assay results are compiled ?
What We Would Like to See
First, we would like the FDA to review previous studies into the connection between DCM and specific diets. We want the agency to enlist the help of the researchers who have conducted these studies.
Here are five:
- Sean J. Delaney and his team found, “The lowest whole blood concentrations were seen in dogs fed lamb or lamb meal and rice diets. Plasma methionine and cysteine concentrations were lower in dogs fed diets with animal meals or turkey, and whole grain rice, rice bran or barley.”
- Kwang Suk Ko and Andrea Fascetti, “Rather than rice, dietary beet pulp showed the most significant effect in lowering plasma and whole taurine concentrations, in part, by decreasing the protein digestibility (sulfur amino acid bioavailability), by enhancing fecal excretion of bile acids and possibly, by enhancing degradation of taurine by the gut microflora in dogs.”
- Robert Backus, “The difference in taurine status between Newfoundlands and Beagles appears explained by differences in de novo taurine synthesis. On the bases of metabolic body weight and liver weight, the Newfoundlands had less than half of the taurine synthesis rates of Beagles.” All dogs were fed the same lamb and rice food.
- Sherry Sanderson, “Results revealed that dogs fed protein-restricted diets can develop decreased taurine concentrations; therefore, protein-restricted diets should be supplemented with taurine. Dietary methionine and cystine concentrations at or above AAFCO recommended minimum requirements did not prevent decreased taurine concentrations. The possibility exists that AAFCO recommended minimum requirements are not adequate for dogs consuming protein-restricted diets. Our results also revealed that, similar to cats, dogs can develop DCM secondary to taurine deficiency, and taurine supplementation can result in substantial improvement in cardiac function.”
Secondly, we believe taurine measurement reference ranges should be revisited, reevaluated and possibly revised. AAFCO may need to change its minimum requirements for methionine, cystine and possibly taurine as well.
Finally, we would like to see a more wholistic approach to the role of the interaction of foods in the gut, gut microbiome, and relevant genetic disposition(s).
Clearly, DCM is more complicated than meets the eye.
Remember, the FDA did not offer any conclusions, simply findings and rather vague suggestions.
If you’ve stopped feeding grains to your companion dog, think back to the many reasons why you stopped. It could be to prevent leaky gut syndrome, to help curb food sensitivities or intolerances to a particular grain, to maintain optimal weight in your dog, etc.
If you are concerned, have your veterinarian take a blood sample to measure the methionine, cysteine and taurine levels in both whole blood and plasma, and send it to a diagnostic laboratory experienced with the appropriate reference ranges for circulating taurine. If the levels are lower than normal for dogs, please discuss the appropriate next steps with your veterinarian. As well, please send the information on your dog, including the food you are feeding, breed, health, age and weight to the FDA no matter what the results are. You and your dog would potentially be helping millions of other dogs.
Adin, Darcy, et al. “Echocardiographic Phenotype of Canine Dilated Cardiomyopathy Differs Based on Diet Type.” Journal of Veterinary Cardiology, vol. 21, Feb. 2019, pp. 1–9., doi:10.1016/j.jvc.2018.11.002. https://www.sciencedirect.com/science/article/pii/S1760273418300882.
Backus, R.C., et al. “Low Plasma Taurine Concentration in Newfoundland Dogs Is Associated with Low Plasma Methionine and Cyst(e)Ine Concentrations and Low Taurine Synthesis.” The Journal of Nutrition, vol. 136, no. 10, 1 Oct. 2006, pp. 2525–2533., http://academic.oup.com/jn/article/136/10/2525/4746691.
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“FDA Investigating Potential Connection Between Diet and Cases of Canine Heart Disease.” U.S. Food and Drug Administration, Center for Biologics Evaluation and Research, 12 July 2018, http://www.fda.gov/AnimalVeterinary/NewsEvents/CVMUpdates/ucm613305.htm.
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