Grain Free Kibble and Heart Disease… the science of kibble-borne disease

Written by Chelsea Kent

Recent reports have been associating grain-free kibble products with an increase in incidence of Dilated Cardiomyopathy (DCM) in breeds that historically have never been diagnosed with this disease.  In theory, the high levels of lectins found in legumes and non-grain binding ingredients are inhibiting conversion of taurine from cysteine. As dogs are more resilient in taurine conversion than cats, it is not required to add Taurine to their diets.

The question becomes what metabolic processes can we confirm that contribute to DCM and is it specific to grain-free kibble?

How does the body get Taurine if its not added in the food? …

In the absence of Taurine the body utilizes the amino acid Cysteine to manufacture it. Cysteine is prevalent in all high-protein foods. Cysteine is oxidized and decarboxylated to form hypo-taurine. The body transfers ions between Copper and Iron to complete this process.

Since Copper is necessary for this life sustaining function, the presence of sufficient levels of Cysteine is necessary to bind Copper Ions (97% of them) to LDL-cholesterol and reduce Copper and Iron in the blood. (1) This process results in a few by-products, one of which is Hydrogen Peroxide which selectively induces cancer cell death. (2) Inadequate levels of Cysteine stops the synthesis of proteins and glutathione which will result in tissue degradation and a variety of metabolic malfunctions. (3)

What non-grain binders contribute that grains don’t: …

Ingredients in dry kibble food products act as binders to allow a product to be made into a pellet shape.  Without these ingredients the product becomes a powder after production. Binders in pet foods can be grains (corn, wheat, soy) or “grain-free” (peas, potatoes, tapioca, and lentils).

All binder ingredients contain assortments of anti-nutrients.  Anti-nutrients are responsible for a variety of functions in a plant and/or animal.  Trypsin Inhibitors, for example, are found in soy, corn and potato.  These anti-nutrients are known to inflame the pancreas which prevents the body from hydrolyzing (digesting) proteins, resulting in Pancreatitis. Phytic Acid, found in beans, grains, nuts and seeds, reduce the absorption of minerals. Lectins, found in beans, grains, nuts, seeds, potatoes and some dairy, mediate attachment and binding to bacteria and viruses. This means (in most cases) that they assist “bad guys” such as Salmonella or Candida in attaching to the epithelial wall of the intestine, increasing the risk of infection and also increasing intestinal permeability. While there are exceptions to this, generally speaking a food must be processed out. Ultimately, grain binders and non-grain binders have similar anti-nutrient capacities and fairly equally contribute to the degradation of health.

To eliminate an anti-nutrient such as a lectin there are a few options:

  • Soak them in water and baking soda for 12+ hours
  • Pressure cook them
  • Peel and De-seed them
  • Ferment them

Dry kibble pet foods do none of these things to ensure low anti-nutrient densities in your pets food. In some cases, this could prove to be highly toxic. As an example, raw kidney beans contain naturally toxic levels of a lectin called phytohaemagglutinin. (4) Lectins decrease the guts ability to heal itself. This creates a “leaky” condition where bacteria, virus, and pathogens perfuse through the intestinal wall and into the blood. Obviously, this requires a decent amount of cleanup, thus decrease immune resources such as Copper and Vitamin D and increasing inflammatory responses.

On rare occasions, certain lectins are necessary to regulate or remediate specific functions to prevent disease.  For example, Mannose-Binding Lectin (MBL) (found in bananas and garlic… foods that dogs and cats don’t eat and if they do they are in insignificant quantities, or manufactured by the body, though sometimes inadequately) were shown in a study published in the American Journal of Pathology in January 2012 to reduce incidence of cardiomyopathy and vascular dysfunction. (5)

You mentioned Copper and Iron earlier… do I need to worry about those in my pets food? Are there other things I should know about metabolism? ….

As noted above, Copper and Iron play a key role in the conversion of Cysteine to Taurine. Albumin, Superoxide Radicals, Zinc, Vitamin C, Vitamin D, Thryoid health and Adrenal all play key roles in your pets Cardiac health and proper metabolic functioning.

Copper is one of the most necessary and beneficial minerals in the body.  It is responsible for numerous metabolic functions and deficiencies result in severe and life threatening illnesses and disease.  Due to its enormous responsibility in the body (all the places it needs to get used, that will suffer if its not available) dietary requirements are fairly high.  One could argue that there is no such thing as a copper toxicity, rather, inadequate metabolic functioning will fail to properly use or bind Copper, resulting in unnatural storage of the mineral.

Cupric Copper is primarily bound to ceruloplasmin and albumin, as albumin’s primary binding site has an affinity for copper.

Bound to Albumin, superoxide radicals and ascorbate anions reduce cupric copper to cuprous copper which catalyzes the formation of a highly reactive and destructive molecule called hydroxyl free radicals. When a Hydroxyl Radical is formed it is likely to attack the albumin molecule it is made from, or any biomolecules near the site where it was created, making the album an important sacrificial molecule.  However, decreased albumin levels (cannibalized by Hydroxyl Radicals) is strongly linked to DCM diagnosis and results in a thickening of capillary basement membranes (DCM), and edema’s such as nephrotic syndrome and protein losing enteropathies. (6)(7) Patients with DCL and Cataracts have been proven to have elevated levels of Hydroxyl Free Radical damage in damaged tissues. If Hydroxyl Radicals are present in conjunction with Polyunsaturated Fatty Acids (PUFA) it immediately initiates lipid peroxidation in the body. This destabilized membranes, resulting in cell death unless Copper levels are sufficient enough to degrade peroxyl and alkoxyl free radicals. (8) Increased production of Hydroxyl Radicals is known to induce cataract formation, cardiomyopathy, and premature aging. (9) Diets high in PUFA dramatically decrease copper dependent metabolic functions and increase production of dangerous free radicals, which forces cells to essentially adopt a cancer metabolism. (10)

As Ceruloplasmin, copper reacts poorly with other components of liver function. However, in the presence of sufficient ascorbate (Vitamin C) copper stores in the liver decreased 2-3 fold, simply because the cells were able to reduce it into a form that safely incorporated and utilized it. Vitamin C was found to regulate Copper and Iron (serum and hepatic levels, absorption and availability at the gut level), Hepatic Microsomal Cytochrome P-450 and Cytochrome B5, and Blood Heme Parameters. (11) As noted above, improper regulation of Copper and Iron results in inadequate conversion of Cysteine to Taurine, leading to chronic heart and eye diseases, as copper bound to ceruloplasmin catalyzes the oxidation of cysteine. (12)

The structure and integrity of the vascular system is intimately related to copper. Copper is required for the production of an enzyme called Lysyl Oxidase, which is involved in the quality and quantity of elastin formation and collagen cross-linking. Without Lysyl Oxidase the vascular system is likely to develop aneurysms, heart enlargement (DCM), heart failure and infarcts. (13)


Hormones and the Endocrine System:

Adequate activity of the sympathetic endocrines (thyroid, adrenal cortex, adrenal medulla, anterior pituitary) increases copper elimination by normalizing metabolic demands. Copper “toxicity” or “storage” therefore, is primarily a by-product of poor metabolic function, not excessive dietary copper intake.

Modern scientific data continues to confirm the value of quality diet and decreased stress on metabolic function, in particular, on endocrine function.

Excess estrogens (caused from environmental exposure or excessive dietary tryptophan) are known to contribute to gall bladder stasis, as well as cholesterol and calcium stone formation. These blockages cause a retention of copper, again, as they prevent normal functions of the body.

Stress induced adrenal gland fatigue cascades to prevent the liver from sufficiently producing ceruloplasmin, which is, again, required to transfer Cysteine to Taurine to protect heart and eye health. (14)

Copper, like so many nutrients, has a symbiotic relationship with multiple nutrients in the body and diet (15):

Increased Zinc = Decreased Copper

Increased Manganese = Decreased Copper

Increased B-Vitamins = Decreased Copper from adequate use

Increased Vitamin C = Decreased Copper from adequate use

Increased Sodium = Increase in Adrenal Hormone Production = Decreased Copper from adequate use

Increased Potassium = Increase in Adrenal Hormone Production = Decreased Copper from adequate use

Increased Copper is a marker for Low Histamine because histamine and Methyl compete with each other

Whoa! I sort of have a headache. Can you summarize all that?

Sure, I’ll try to make it short and without the confusing words.

  • Dogs aren’t supplemented with Taurine
  • Dogs create Taurine from Cysteine
  • In order for Cysteine to convert to Taurine and protect the heart the body needs the right amount of Copper and Iron
  • Certain things prevent the body from supporting this conversion process: – Supplementation with Polyunsaturated Fats (oils), – Excess Zinc, – Excess Manganese, – Deficient Vitamin C, – Deficient Vitamin D, – Inadequate Thryoid Function, – Inadequate Adrenal Function, – Deficient Copper, – Blockages, – Deficiency of Mannose-Binding Lectins (which should be manufactured by the body)
  • Phytic Acids (antinutrients found in grain and non-grain binder ingredients) prevent the absorption of minerals such copper and iron which may result in DCM and other deficient diseases
  • Trypsin inhibitors (antinutrients found in grain and non-grain binder ingredients) inflame the pancreas and prevent the body from hydrolyzing proteins which may result in a variety of diseases associated with inadequate nutrient absorption or metabolic function
  • Lectins (antinutrients found in grain and non-grain binder ingredients) contribute to leaky gut, inflammation, and possibly bacteria food poisoning.  These conditions require nutrients such as Copper and Vitamin D, thus reducing stores available for metabolic functions such as the conversion of Cysteine into Taurine.

So, is it Grain-Free Kibble that causes Dilated Cardiomyopathy?  No.  Its Dry Kibble of any kind that can cause metabolic abnormalities that could result in conditions such as low thyroid or adrenal function, digestive disorders and vascular disorders such as Dilated Cardiomyopathy in any dog.
















2 thoughts on “Grain Free Kibble and Heart Disease… the science of kibble-borne disease

  1. So does the study that is reported as new information regarding grain-free kibble, and associating specific cases of DCM with specific formulas (the Acana Pork and Squash singles) – contain any context or information allowing comparison with similar formulas using grain? Was there any evidence suggesting the study designers had an axe to grind? From your analysis it looks as though various combinations of ingredients could be more or less likely to lead to taurine depletion. Is that correct?


    1. There are not yet any confirmed comparative studies. And yes, there are several factors that would contribute to DCM development, which explains why not all dogs develop it despite consuming these foods for a life time. For example, excessive iron levels caused by Spay or being male would increase incidence. The addition of any form of unsaturated fatty acid (fish oil or other omega 3) would increase incidence by increasing production of free radicals. Increased vaccines or heavy metal contamination would increase incidence by taxing the body. Decreased thyroid or adrenal function would increase incidence by inhibiting cysteine conversion. Zinc supplementation would increase incidence by decreasing copper availability, thus making conversion impossible. There are a host of concerns that would create a larger concern for your pet. The moral of the story is that fresh food sources would resolve all of these concerns whereas ALL kibble products, grain and non-grain, will contribute.


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