The Taurine Controversy

Dilated Cardiomyopathy (DCM) in dogs eating grain-free diets is a hot topic in pet news right now.  Many pet parents feel concerned, confused, frustrated and even a little misdirected right now.  The implication is that pet foods that don’t contain grains are in some way missing a vitally important nutrient, Taurine, and that this inadequacy is resulting in life threatening disease.

Is it really the case that because a food doesn’t contain grain it is nutritionally inadequate? Or are pet parents being fooled by Big Kibble to feed inexpensive kibbles, rich in grains? There are a few factors to consider when determining your pets risk of developing diet-induced DCM.

Regulatory Inadequacy or Product Inadequacy? Who is to blame?

  AAFCO (Association of American Feed Control Officials) is responsible for providing pet food manufacturers with guidelines to help them determine the nutritional adequacy of their products. In 1975, when there was a DCM epidemic in cats fed grain-laden kibble foods, AAFCO decided not to make any nutritional suggestions or requirements for Taurine supplementation in canine diets, even though they recognized the need for adjustments in feline diets.  Other clinical diseases caused by Taurine deficiency included feline central retinal degeneration, dilated cardiomyopathy, reduced reproductive performance, and growth, motor and immune disorders. (HAYES et al., 1975; PION et al., 1987). (7) While DCM has not been linked to dietary inadequacies in dog food, no research has been done prove that dietary inadequacies are not the cause either. Rather, science chalked up this disease to “genetics” alone. To date, data regarding any potential increases in DCM prevalence is sparse. It is becoming clearer that while some breeds may be more genetically equipped to endure a lifetime of nutritional abuse, less-adept breeds (Golden Retrievers, Dobermans, Great Danes, Boxers, Newfoundlands, Irish Wolfhounds and Saint Bernards) consuming grain-rich dry kibble foods regularly developed DCM before grain-free options were available.

The important thing to remember, though, is that all manufacturers of grain-Free and grain-containing pet foods are in compliance with AAFCO nutrient requirements. There continues to be no requirements for any manufacturer to add not only Taurine to canine diets, but also Methionine or Cysteine, its dietary precursors. Ultimately, the primary source of this problem, then, is regulatory failures.  Is this the only cause of DCM though? And how can you protect your pet if no pet food is required to contain this protective nutrient?

Well then, is it even true that dogs fed grain-free diets are developing DCM?

Yes, but historically most dogs diagnosed with DCM consume diets that contain grains.  Comparative studies have not yet been finalized to determine if there is any increase in risk of DCM in pets fed grain-containing or grain-free foods. (1) Current FDA reporting clearly states that an equal number atypical dog breeds (that do not have a genetic propensity to develop DCM) recently diagnosed with DCM have not been found to be Taurine deficient.  This implies that perhaps Taurine is not the issue, or at the least, not the ONLY issue that pet owners need to be concerned about regarding AAFCO’s nutritional adequacy recommendations in processed kibble food products. (2)

What is causing this?

No one knows yet! However, it has been proven that DCM can be caused by taurine deficiency, carnitine deficiency, methionine/cysteine deficiency, genetics, infectious disease, chemotherapeutic toxins, and immunological cellular damage. (3) Other theories propose that the fiber or sugars (polysaccharides) in the GI tract are blocking taurine absorption or that anti-nutrients called lectins (also found in grains) are a contributing factor. (4) The assortment of potential causes makes it difficult to determine dietary risk as compared to environmental or genetic risk.

Do foods that contain grains ever cause Taurine deficiency?

Yes.  The Grain-Free pet food “trend” began in 2012. (5) However, a 2010 study on 775 dogs diagnosed with DCM referenced DCM trends in dogs as far back as 1982, 30 years before grain-free diets were available(6)

 What about Raw Diets? How likely are they to cause DCM?

A study published by the Department of Molecular Biosciences, School of Veterinary Medicine, UC Davis (7) determined the following Taurine trends in animal feed products:

–          Animal muscle tissue, particularly marine and turkey, contain high taurine concentrations.

–          (All) plant products (fruits, veggies, grains, soy, nuts, seeds, and tapioca) contained either low or undetectable amounts of taurine. Processed kibble diets contain between 30-90% non-meat ingredients. Whether your pets’ food contains grains or grain-free alternatives, these Taurine deficient binding ingredients all dilute the naturally-occurring Taurine found in meats. Raw pet foods, however, do not require (or generally add) significant amounts of non-meat products and do not contain binders that dilute necessary Taurine.

–          The amount of taurine that remained in a feed ingredient after cooking depended upon the method of food preparation – with no Taurine loss in raw meats, and significant losses in baked or boiled meat products. All processed pet food products must be heated, which ensures that naturally-occurring Taurine levels are inadequate. How adequate can feeding fresh, raw food be for your pet? AAFCO’s highest Taurine requirement for cats is .5g/1000kcal. Raw Lean Beef (one of the most inadequate sources of naturally occurring Taurine) was shown to contain 1% more Taurine than AAFCO’s highest nutritional taurine requirement(8)

–          There is a broad range of taurine concentrations between meats of varying quality, species, environments and processing methods. Cost conscious pet food manufacturers commonly use Mechanically Deboned Meats (MDM) and Meat Meals in products.  AAFCO’s minimum Taurine requirement for cats is .25g/1000kg. MDM/Meat Meals provide 38% less Taurine than AAFCO’s minimum feline standard, and that’s prior to processing that contributes to additional Taurine loss. (8)

Seventeen years ago, in 2001, scientists stated, “From an evolutionary standpoint, taurine was plentiful in the diet of a true carnivore, as high concentrations of taurine are found in the muscle tissue. However, as most domesticated felines normally do not consume living prey, they are at risk to become taurine deficient if not adequately supplied in the diet…. However, nutritional paradigms have been recognized to result in taurine deficiency in dogs. In many cases, taurine deficiency was also associated with dilated cardiomyopathy.” (7) (BACKUS et al., 2001)

What about synthetic supplementation of Taurine?  Is that a safe and/or adequate option?

Yet another regulatory failure … synthetic Taurine manufacturers are not required to produce studies to determine tolerance, metabolism and residue, and toxicological effects (concerning consumer safety). (9) Therefore, supplementation of synthetic Taurine to grain-containing and grain-free diets is questionably safe.

One brand of a “Cardiac Support” dry kibble (rich in grains) contains 0.18% Taurine. (10) AAFCO requires 0.1% Taurine in Cat Foods, so this dog food meets AAFCO feline standards. (8) However, feeding a kibble product still runs the inescapable risks of feeding kibble or canned that are listed below:

1)      AAFCO does not require supplemental carnitine, methionine or cysteine (found naturally in fresh, raw meats) which are precursors to Taurine conversion

2)      Kibble and canned foods are cooked and processed (lending it to  further nutrient losses)

3)      Binder ingredients, such as Brewers Rice, Soy Protein Isolate and Powdered Cellulose do not contain Taurine and dilute the Taurine content in meats.

4)      Binder ingredients contain lectins, fibers and polysaccharides that may inhibit Taurine absorption or conversion.

Considering that no commercially available dog food is required to add Taurine or its amino acid constituents, and the safety of synthetic Taurine is questionablethe best way for Pet Parents to protect their pets from disease conditions caused by nutrient deficiencies or inhibiting ingredients is to place their trust in nature, not regulators. AAFCO has proven again that their knowledge of nutrient requirements in pets is as inadequate as their recommendations, and sadly this has cost the lives of hundreds of thousands of animals in the decades AAFCO has been in existence. Nature, however, continues to provide safer, more adequate and more comprehensive nutrients than AAFCO in the form of fresh, raw, whole foods… and we didn’t even have to ask!

1)        https://www.petfoodindustry.com/webinars

2)        https://www.fda.gov/animalveterinary/newsevents/cvmupdates/ucm613305.htm

3)        https://centredmv.com/wp-content/uploads/2013/09/Dilated-cardiomyopathies-in-dog.pdf

4)        https://www.facebook.com/doctor.karen.becker/videos/10156521657422748/

5)        https://blog.euromonitor.com/2012/06/consumer-interest-in-grain-free-pet-food-grows.html

6)        https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1939-1676.2010.0479.x

7)        https://www.vetmed.ucdavis.edu/sites/g/files/dgvnsk491/files/aal/pdfs/spitze.pdf

8)        https://www.aafco.org/Portals/0/SiteContent/Regulatory/Committees/Pet-Food/Reports/Pet_Food_Report_2013_Midyear-Proposed_Revisions_to_AAFCO_Nutrient_Profiles.pdf

9)        https://efsa.onlinelibrary.wiley.com/doi/pdf/10.2903/j.efsa.2012.2736

10)     https://www.royalcanin.com/products/royal-canin-veterinary-diet-canine-early-cardiac-dry-dog-food/3930

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