Integrative Pet Vet column: Grain-free foods, taurine deficiencies and heart disease in dogs
Integrative Pet Vet
Taurine deficiency in dogs eating grain-free foods has received growing attention. This was triggered by an observed correlation between dilated cardiomyopathy (DCM), response to taurine, and feeding grain-free foods. Obviously this raised concerns that these foods were insufficient in taurine to prevent DCM. Keep in mind that this association was noted in a small number of dogs, and the full magnitude of the problem is not yet clear. It has also spurred increased awareness and renewed research to better understand the correlation in affected dogs.
Cardiomyopathy is a term used to indicate a problem with the heart muscle. Taurine deficiency and cardiomyopathy were clearly demonstrated in cats in the late 1980s but the connection in dogs with cardiomyopathy could not be fully determined. In the 1990s an association between DCM and low taurine levels was found in the American cocker spaniel breed. Since then, other breeds have been identified with low taurine DCM. However, there have been studies showing low taurine levels and no DCM as well as DCM in some breeds even when the taurine level is adequate. These patterns of conflicting results made the role of taurine deficiency and DCM in dogs unclear.
Taurine is an amino acid. Amino acids are assembled to make proteins. Proteins are vital for basic life functions because they form substances like enzymes, cell membrane receptors, cell structure components, hormones like insulin, and antibodies, and they maintain fluid balances. Some amino acids are considered essential because the body cannot make them and they must be in the diet. There are 10 amino acids that are considered essential in the dog. Note that taurine is considered essential in cats but not in dogs. Other amino acids like glutamine are considered to be conditionally essential. This means that they can be produced in limited amounts in the body but not always in the amounts that are required. In some situations supplementation with the conditionally essential amino acid is beneficial for addressing a health problem. Taurine supplementation in some dogs with DCM has been beneficial.
Taurine has wide distribution in the body and is important for many body systems including the heart, skeletal muscle, central nervous system and retina. It has benefits for heart contractions, synthesis of bile salts, sight, hearing, nerve conduction, movement of calcium across cell membranes and protection of cell integrity. There may also be a role in managing anxiety and calming the sympathetic nervous system.
Taurine is present in highest amounts in animal tissues like heart, liver, kidney, muscle, fish and poultry. The amount of taurine in these tissues can vary widely. Plants are poor sources of taurine. Methods of ingredient storage and food preparation have significant impacts on the amount of taurine available in the final food product. Since taurine is water soluble, the more water that is used in preparation, the more likely that taurine will be lost in the processing. For example, in order to provide adequate levels of taurine, wet cat food requires twice the amount of taurine added during preparation compared to dry cat food.
In addition to the effect that ingredients and method of food preparation have on the amount of taurine available in the final food, there is also variation in the amount of taurine that an individual needs. Taurine may be deficient in an individual dog regardless of the amount in the food because there is insufficient taurine synthesis or excess taurine loss in the urine or intestine. These factors together result in variation in the optimal amount of taurine supplementation that is required. It also makes determining if a particular diet is adequate in available taurine challenging.
While research is ongoing to determine the role of specific food formulations and DCM in dogs, there are a number of approaches that can be taken to support dogs that may be at risk. This includes changing the diet to foods that have traditionally been considered adequate; however, this approach has its own issues of concern. Another approach is to measure the blood levels of taurine and base decisions for supplementation and/or food changes on those levels. Some authorities consider supplemention without knowing the current taurine blood levels to be safe.
If you have concerns about taurine and the current focus on grain-free diets, contact your veterinarian.
Ron Carsten, DVM, PhD, CVA, CCRT was one of the first veterinarians in Colorado to use the integrative approach, has lectured widely to veterinarians, and has been a pioneer in the therapeutic use of food concentrates to manage clinical problems. He is also the founder of Colorado Animal Rescue (CARE). In addition to his Doctor of Veterinary Medicine, he holds a PhD in Cell and Molecular Biology and is a Certified Veterinary Acupuncturist and Certified Canine Rehabilitation Therapist. He practices integrative veterinary medicine in Glenwood Springs.
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