Study summary · Dogs · Taurine and heart health · Kaplan et al., 2018
Many affected dogs improved after combined treatment.
This study described Golden Retrievers with both low taurine and dilated cardiomyopathy, a disease affecting the heart muscle. Most dogs with follow-up heart scans improved after diet changes, taurine supplementation and clinical care. Because several treatments changed together and there was no untreated comparison group, the study cannot identify one responsible ingredient or separate the effects of each treatment.
Why this study matters
Diet-related heart-disease claims can be alarming. This paper matters because it followed dogs with diagnosed illness and measured changes in heart function. It also illustrates the difference between identifying a concerning association and demonstrating that a food category or ingredient causes disease.
How the study worked
Participants
The clinical group included 24 client-owned Golden Retrievers with documented low taurine and dilated cardiomyopathy, recruited through veterinary centres in North America between January 2016 and July 2018. Ages ranged from one to eleven years. Eleven had congestive heart failure. A separate screening group comprised 52 apparently healthy Golden Retrievers. These groups were recruited for different purposes and were not a random sample of all dogs.
What happened?
Clinicians collected diet histories, taurine measurements and echocardiograms. Affected dogs were prescribed taurine and a change of diet, with some also receiving L-carnitine and heart medicines. Treatment was chosen by the attending veterinarian, not randomly assigned or standardised. Follow-up heart scans were available for 16 of the 24 affected dogs, at a median of 250 days, with a wide range of 26 to 860 days.
The comparison
Researchers compared affected dogs with their own starting measurements. There was no randomised diet or untreated control group. The separate apparently healthy group provided taurine-screening data and diet histories, rather than a matched comparison for treatment effectiveness.
What was measured?
The main clinical measurements were heart size and pumping-function indices on ultrasound, blood taurine, and whether congestion resolved in dogs with heart failure. Diet histories were used to examine associations. Whole-blood, plasma and serum taurine measurements were not all available for every dog and should not be treated as interchangeable.
What the researchers found
| Outcome | Reported result | How to read it |
|---|---|---|
| Diet histories | 23 of 24 affected dogs had eaten diets categorised as grain-free, legume-rich or both. | The sample was selected because dogs were already affected. This is not the probability that a dog eating one of those foods will develop disease. |
| Heart ultrasound follow-up | 16 of 24 dogs had follow-up echocardiograms; the discussion reports improvement in 15 of those 16. | Use the follow-up denominator. Eight enrolled dogs did not have repeat heart-scan data available. |
| Congestive heart failure | Congestion resolved in 9 of the 11 dogs initially diagnosed with heart failure; one remained affected and one was lost to follow-up. | These dogs received clinical treatment. The result cannot be attributed to changing food alone. |
| Taurine follow-up | Follow-up taurine results were available for 15 dogs. Of 14 with whole-blood follow-up, 13 exceeded the study threshold of 250 nmol/mL. | The threshold was chosen for this study and breed. It is not a universal home diagnostic rule. |
Published correction checked: the December 2018 correction fixes an author name and removes the grain-free and legume-rich labels from diet row 8L. We have considered that correction and do not reproduce the original diet-classification table. Read the correction.
What strengthens the evidence?
The study involved pets receiving care across several centres, included detailed diet histories and used objective cardiac imaging. A single investigator reviewed the echocardiograms, improving consistency of assessment. Follow-up data allowed the researchers to describe change within individual dogs rather than simply comparing unrelated groups at one time.
What limits the conclusions?
The clinical sample was small, selected for both low taurine and heart disease, and restricted to one breed. There was no random allocation or untreated comparison. Changes in diet, supplements and medicines occurred together, so their separate contributions cannot be determined. Heart-scan follow-up was available for only 16 of 24 dogs and taurine follow-up for 15, with variable timing. The separate screening sample does not establish population prevalence. Diet histories and ingredient labels cannot identify a causal nutrient mechanism, and unmeasured differences between dogs and diets remain possible. The abstract gives a broader impression of follow-up coverage than the detailed results, so the results below use the outcome-specific denominators.
What the researchers concluded
The authors considered taurine deficiency and dilated cardiomyopathy in these Golden Retrievers likely to have multiple contributing factors, including diet, metabolism and genetics. They reported dietary associations and improvement after combined intervention, while calling for further investigation of the mechanisms.
Evidence.pet interpretation
The clinically relevant finding is that many dogs with this particular combination of diagnoses improved during treatment. It is not proof that all grain-free foods cause heart disease, that every legume is harmful, or that taurine alone explains every case of canine cardiomyopathy. This is a historical study of selected cases, not a current safety ranking of products. A pet owner concerned about diet and heart health should bring the exact food and supplement history to their veterinarian; this paper is not a basis for diagnosing deficiency or choosing a supplement dose at home.
Funding and author interests
The authors reported no specific funding for this work. Andrea J. Fascetti disclosed being Scientific Director of the University of California, Davis Amino Acid Laboratory, which provides testing for a fee. The paper states that this did not influence data collection or interpretation. Relevant data are presented within the article.
Read the original research
Kaplan JL, Stern JA, Fascetti AJ, Larsen JA, Skolnik H, Peddle GD, et al. Taurine deficiency and dilated cardiomyopathy in golden retrievers fed commercial diets. PLOS ONE. 2018;13(12):e0209112. doi:10.1371/journal.pone.0209112. Read with the correction, PLOS ONE. 2018;13(12):e0210233.
Evidence.pet editorial summary · Study ID STU-007 · Source checked 22 September 2026. Strengths, limitations and interpretation are our editorial assessment, not a formal evidence grade.
Adapted from Kaplan and colleagues and their published correction under CC BY 4.0, with original Evidence.pet interpretation.
Creative Commons Attribution 4.0 licence. The source has been condensed and reorganised.