There are 22 amino acids, the basic building blocks of protein. Animals can manufacture many of them in their liver, but some must be obtained in the diet—these are called ‘essential.’ In humans and dogs, taurine is not ‘essential’, since it can be synthesized within the body. But for cats, it’s a different story.
Taurine is a lesser known amino acid that until recently, has remained under the radar. It isn’t part of the muscle protein yet plays an important role in metabolism, especially in the brain.
Taurine functions in the brain and heart to help stabilize cell membranes. It also has functions in the gallbladder, eyes, and blood vessels and appears to have some antioxidant and detoxifying activity. Taurine also aids the movement of potassium, sodium, calcium, and magnesium in and out of cells and thus helps generate nerve impulses. It is found in the central nervous system, skeletal muscle, and heart; it is very concentrated in the brain and high in the heart tissues. It is found in high amounts in meat and fish proteins.
Dogs and Taurine
Dogs synthesize taurine from the sulfur amino acids cysteine and methionine, so taurine is not required to be added to the diet for healthy dogs. A number of years ago taurine deficiency was noted in some dogs that had DCM (Dilated Cardiomyopathy). These dogs were eating a variety of dog foods, some of which were homemade, but which were sufficient in protein (and amino acid profiles), and had passed AAFCO feeding trials. Although the cause of taurine deficiency was not readily apparent in these dogs, or any dogs, there may be a link genetically or metabolically. Large and giant breed dogs such as Newfoundlands, and American Cocker Spaniels appear to be particularly susceptible.
Cats and Taurine
Cats are not able to synthesize taurine within their bodies, so adequate amounts of taurine must be provided in their diets. Early on in the pet food industry, taurine deficiency was noted in cats, due to the use of many plant-based proteins, and high carbohydrates. This deficiency caused blindness, heart troubles, and other maladies. Once commercial cat diets were noted as being deficient of taurine, it was put on the list of “essential amino acids” for cats, and modern day cat foods now must ensure they provide adequate amounts.