Worried About Grain-Free Diets & Heart Disease? Take Heart!

Grain-free.  These two words are the focus of a recent media storm creating trouble for pet food.  The confusion originates from a July 2018 report by the Federal Food and Drug Administration (FDA) and research conducted by Dr. Joshua Stern, DVM, PhD, DACVIM, Chair of the Department of Veterinary Cardiology at UC-Davis. Dr. Stern is investigating the possible reasons specific “grain-free” dry kibble foods have been implicated in cases of canine Dilated Cardiomyopathy (DCM).

Alarmed from media reports, clients feeding grain-free foods to their pets may have serious questions. Let’s get to the heart of the matter and examine the issue more closely.

 What does grain-free really mean?

The term “grain-free’ does not refer to any specific type of food. The grain-free label simply means that the food contains no grains. The term itself does not define anything really important about a pet food.

Why did grain-free foods become popular in the first place?

As veterinarians, most of us were taught that grains are an acceptable, significant part of the canine diet. However, large quantities of grains in dog food were never a good idea. The formulas themselves and the way the food was manufactured and processed have been sources of concern.

The market responded to these questions by simply replacing grains with other inappropriate ingredients, and a huge market for grain-free food was born. This strategy assumed that the only complaint about kibble foods was the inclusion of grain, and that by removing the grain, the diet would be healthier. This turned out to be a great marketing strategy, but didn’t necessarily create healthier foods. Instead of creating foods with healthy meats and fresh ingredients, the added niche of “grain-free” only added a new burden to the overload of inappropriate pet food on the market.

The market was flooded with foods that were “grain-free” but just as flawed. High heat-processed, nutritionally damaged, industrially sourced pet food too high in carbohydrates and too low in quality proteins and healthy fats is still an unhealthy diet, regardless of the grain-free label on the bag.

Why are grain-free foods being linked to heart disease in dogs?

The new substitutes for grain (potatoes, tapioca, legumes/beans, and many other plant-sourced carbohydrates) may be triggering a worse and more dramatic problem.

Because they provide some protein, these plant-based grain substitutes allow manufacturers to lower the amount of meat-based protein in their formulas. But these plant-based proteins do not possess a complete amino acid profile, most notably lacking in taurine, an amino acid required for cardiac health in dogs and cats found in animal-based foods

The link between dietary taurine deficiency and heart disease is well described in the cat.  Cats can’t make taurine from other sources and cats deficient in taurine can develop heart disease. In contrast, dogs with the right building blocks can make it themselves. Therefore, taurine is not considered an essential amino acid for dogs. Taurine content was ignored in AAFCO recommendations for dog foods. There is little data and no guidelines about taurine in dogs available from the Association of American Feed Control Officials (AAFCO), FDA, or the U.S. Department of Agriculture. Often these organizations don’t concern themselves with every component of a food.

We had not seen significant taurine-related canine heart problems in the past. Until recently, the majority of dog foods were formulated with enough meat-sourced proteins to provide the base amount of taurine needed for most dogs. Now with “grain-free” dry foods, pet food quality has reached a new low.

Without minimum recommended levels of taurine for dog foods, companies making these foods have not been held accountable for poorly conceived diets. Other factors also affect the bioavailability of the taurine that is present in the diet.

Additional causes of dietary taurine deficiency

Food Preparation

Cooking meats degrades and drastically reduces the bioavailability of taurine in the food. If meats are cooked in water and the water is discarded, most of the taurine can be lost.

Moisture removal to make a dry food further depletes taurine in foods already deficient. Taurine amounts can be diminished somewhat when foods stay frozen for long periods of time as well, but not as much as the loss from cooking.  If there is enough fresh meat, typically there will be enough taurine in a short-term frozen raw food.

Bile Salt Conjugation

Both dogs and cats constantly lose taurine through bile salt conjugation, especially if bile salts are not recycled by the body because they are bound by starchy compounds like rice bran or beet pulp. Both ingredients can be found in grain-free and grained foods. Dogs and cats will have an increased need for taurine if they are eating foods with these components.


Microbiome deficiencies cause the body to absorb taurine and other vital nutrients inadequately.

Highly processed, heat-treated, poorly balanced dry foods high in carbohydrates and starch not only overfeed the wrong species of bacteria for a dog’s gut, but also fail to replenish  appropriate bacteria or strengthen the microbiome.

Many pet foods source ingredients from industrial farming where antibiotics and chemicals are used. These will be present in the pet food and affect the microbiome of the pet.


The diet’s packaging also affects the bioavailability of taurine. Conscientious manufacturers of canned foods for cats typically double the amount of taurine in the food due to concerns that taurine availability may be affected by the canning process.

What does this mean for our patients on grain-free diets?

Pet owners searching for better answers are swayed by marketing, catch phrases, convenience, fancy packaging and perhaps overwhelmed by the glut of good and bad information online. But we all have the same intention. We want to provide our pets and patients with a happy and healthy long life.

The circulating news stories suggest that if we all revert to feeding our pets grains in their dry kibble foods, health will return.

However, we are not to assume that ALL grain-free food is unhealthy or that ALL grain-free food causes heart disease.

Keep the basics in mind about diet. Don’t let clients run back to a diet with grain thinking it is protective to the heart. That is not the answer.  What is in the food matters certainly as much as what is kept out of it.

Here are several practical ideas and tips about diets and taurine to help clients avoid more health risks with each new “pet food fad.”

I suggest veterinarians strive to provide the building blocks of health, evaluate pet food recipes, and focus on prevention.

Look for fresh, balanced, moisture-appropriate food for a carnivore. We can keep animals and their hearts healthy with the foods they are designed to feast upon. Use a fresh, species-specific diet as a sensible starting place to create health.

Remember that taurine is nearly non-existent in many plant-based proteins.  We must evaluate ingredients in both dog and cat diets for taurine, regardless of the AAFCO standards.

Look for quality, organic, non-GMO meat sources of protein high on the pet food label.

Don’t focus on choosing between a dry kibble that has either grains or is grain-free (two bad choices) – choose balance and freshness wherever possible.

Add a fresh meat source to pet food — taurine is typically high in many animal-based proteins especially sardines, shrimp, clams, scallops, fresh uncooked dark meat poultry, and heart muscle. Tuna is not a source of taurine. If a fully fresh diet is not possible, try to at least supplement with something fresh. Fresh healthy foods will keep pets healthy!

It is interesting to note that cats who eat mice are not likely to have any taurine deficiency as mouse muscle and particularly a tiny mouse heart contains very high concentrations of taurine.

 Add a probiotic/prebiotic or healthy goat yogurt/milk to help regain a healthy microbiome for better absorption of nutrients.

Consider using a well-balanced, well-sourced fresh raw food recipe in your pet’s weekly rations.  Remember that variety helps provide balance too.

Many people in the pet food industry are recognizing that the future of pet food is moving towards functional pet food nutrition — ingredients designed and combined for optimizing the individual’s health needs, using software tools like the Animal Diet Formulator™. The data available in the Animal Diet Formulator™ (ADF) software provides a tool used by Royal Animal Health University to teach veterinarians and technicians to evaluate and create recipes and diets. It is an unusually complete and useful tool, in that it includes taurine as well as corrected USDA data on many other ingredients to help us find optimal levels for nutrients and keep up with these health concerns. Hopefully the current research by Dr. Stern will add to our understanding and knowledge about these important micronutrients.

What about supplementation?

If an animal has a heart condition and taurine might be a factor, consider suggesting a taurine supplement to a diet. For cats the literature suggests about 75-100 mg of taurine daily. For dogs, the levels are typically extrapolated, but it is difficult to overdose (it is excreted rather than stored in the body). Literature references about 500 mg for a 30lb dog up to three times a day as a good place to start. It can take several months to see cardiac improvement, but if a taurine deficiency was at the heart of the problem, it may fully resolve with supplementation. Use organic and well-known sources.

Certainly breeds predisposed to Dilated Cardiomyopathy (DCM) that can be more strongly affected by taurine deficiency might benefit from added taurine – either in foods or supplements. These breeds include Golden Retrievers, Doberman Pinschers, Great Danes, American Cocker Spaniels, Boxers, and other large breed dogs.

Consider using freeze dried heart treats to help increase amino acids, including taurine.

Dogs with urate or cystine stones should consider taurine supplementation because the body uses these as building blocks for taurine synthesis.

Finally, we must remember that food is medicine. While a good diet cannot cure all ills, a poor diet will always create problems. With proper nutrition, there is a strong tendency for health.

Additional information

To test a pet’s amino acids/taurine levels:

University of California Davis Amino Acid Laboratory

Diet and Taurine Research:

Wójcik OP, Koenig KL, Zeleniuch-Jacquotte A, Costa M, Chen Y. “The potential protective effects of taurine on coronary heart disease”. Atherosclerosis. 2010 Jan; 208(1):19-25. doi: 10.1016/j.atherosclerosis.2009.06.002. Epub 2009 Jun 11.

Ko KS, Fascetti AJ. “Dietary beet pulp decreases taurine status in dogs fed low protein diet”. J Anim Sci Technol. 2016 Aug 2;58:29. doi: 10.1186/s40781-016-0112-6. eCollection 2016.

Backus RC, Cohen G, Pion PD, Good KL, Rogers QR, Fascetti A.J. Taurine deficiency in Newfoundlands fed commercially available complete and balanced diets. J Am Vet Med Assoc. 2003 Oct 15;223 (8):1130-6.

Fascetti AJ, Reed JR, Rogers QR, Backus RC. Taurine deficiency in dogs with dilated cardiomyopathy: 12 cases (1997-2001). J Am Vet Med Assoc. 2003 Oct 15;223(8):1137-41.

Torres CL, Backus RC, Fascetti AJ, Rogers QR. Taurine status in normal dogs fed a commercial diet associated with taurine deficiency and dilated cardiomyopathy. J Anim Physiol Anim Nutr (Berl). 2003 Oct;87(9-10):359-72

Belanger MC, Ouellet M, Queney G, Moreau M. Taurine-deficient dilated cardiomyopathy in a family of Golden Retrievers. J Am Anim Hosp Assoc. 2005 Sep-Oct;41(5):284-91.


Journal of Animal Physiology and Animal Nutrition.  87(7-8):251-62,  September, 2003


Microbiome Research:






Mitochondria + Microbiome: