Taurine has become a hot-topic in pet food over the last few years. Though taurine requirements are well established in cats, it’s a little more complicated for dogs. Read on to find out everything you need to know about taurine and dogs, including which breeds may be at increased risk of developing taurine deficiency…
What is taurine?
Proteins are found inside every cell of the body and play a huge role in its structure and function. Amino acids, like taurine, are the building blocks of proteins. Essential amino acids can’t be made by the body and need to come from the diet. Non-essential amino acids can be made by the body.
In dogs, taurine is considered one of the non-essential amino acids, so, according to the nutritional standards set out by the Association of American Feed Control Officials (AAFCO), there is no established requirement for the amount of taurine in dog food.
There are, however, minimum levels of the essential amino acids methionine and cystine that must be present in all complete and balanced dog foods. Dogs require both of these amino acids to be able to produce taurine.
Though this seems to be adequate for most dogs, there is still debate and ongoing research as to the importance of taurine in dog food. Studies have suggested that certain large-breed dogs may have more difficulty producing or metabolizing taurine, but there isn’t enough evidence to make clear recommendations at present.
Why is taurine important for dogs?
Taurine is found in high levels within the heart, the retina of the eye, and the brain. If taurine levels are too low (taurine deficiency), these organs and body systems can develop disease.
Taurine-related Heart Disease
Dilated cardiomyopathy (DCM) is a heart condition where the muscle walls become too thin and the chambers of the heart become too large. If these changes can’t be reversed, DCM will sadly lead to heart failure and death as the heart has to work harder and harder to pump blood around the body. Taurine is an essential amino acid in cats and deficiency in their diet causes DCM.
But what about dogs? In 2018, a series of cases of DCM in dogs was linked to boutique grain-free diets, many of which contained exotic ingredients (such as venison, kangaroo, or buffalo) and legumes (such as lentils or peas).
Many of these dogs improved when their diet was changed, which suggests a possible nutritional cause. Given the association in cats, a taurine deficiency was suspected, however, most of the dogs tested had normal taurine levels.
This doesn’t necessarily rule out problems with taurine metabolism or other interactions within the body but unfortunately, there are still no conclusions as to why these dogs developed DCM. An FDA (U.S. Food and Drug Administration) investigation is still ongoing.
Taurine-related Eye Disease
Taurine deficiency in cats is also associated with an eye condition known as Feline Central Retinal Degeneration (FCRD). This disease causes the cone cells of the retina to deteriorate, leading to vision loss and blindness if left untreated.
Though this disease is considered specific to cats, there have been reports of dogs diagnosed with taurine deficiency that have also developed retinal degeneration.
What causes a deficiency in taurine?
Most dogs can make enough taurine to stay happy and healthy when fed a complete and balanced diet that meets AAFCO nutritional standards. Dog foods that meet these criteria must contain adequate levels of methionine and cystine (the precursors that the body uses to make taurine).
Diets low in taurine
Home-cooked diets or any diet that doesn’t meet these standards put your dog at risk of developing nutritional deficiencies, including taurine deficiency. If you choose to prepare your own pet food, it’s important to use a recipe created especially for your dog by a board-certified veterinary nutritionist to avoid these issues.
As previously mentioned, boutique grain-free diets with exotic ingredients have also been associated with cases of DCM in dogs but the underlying reason for this is still unknown. It’s not clear that taurine was the cause of these problems.
Breeds prone to taurine deficiency
Here’s where it gets even more complicated. Certain large-breed dogs seem to be more likely to develop taurine deficiency or diseases associated with it (DCM), even if their diet contains appropriate levels of methionine and cystine. Breeds associated with taurine deficiency or DCM include:
- American Cocker Spaniels
- Golden Retrievers
- English Setters
- Saint Bernards
- Irish Wolfhounds
Reasons as to why these breeds are more likely to develop taurine deficiency or DCM are still unknown. Possible causes include genetic factors, metabolic differences between breeds, and increased loss of taurine through the urine, but further research is required to understand exactly why these dogs are more likely to be affected.
Is your dog at risk?
Dogs that suffer from diseases that affect amino acid absorption or metabolism such as cystinuria (formation of cystine crystals or stones in the urine), may also be at risk of developing taurine deficiency.
Any of the breeds listed above or dogs that are fed a vegetarian or vegan diet, home-cooked diet, grain-free diet, or a boutique diet containing exotic ingredients, may also be at increased risk of developing a taurine deficiency or DCM.
If you’re concerned your dog may be at risk, it’s best to speak to a veterinarian or a board-certified veterinary nutritionist who will discuss the risks with you. It’s important to keep in mind that taurine deficiency and DCM are relatively uncommon and, in most cases, your vet will simply recommend feeding an appropriate diet and monitoring their health closely. Diagnostic testing may be recommended if your veterinarian is concerned or there is a known family history.
How to diagnose a taurine deficiency?
The most common way to diagnose a taurine deficiency is to have your veterinarian run a blood test. A whole blood test for taurine levels is most common, however, your vet may also want to perform more comprehensive blood and urine testing too.
If a taurine deficiency is diagnosed or your veterinarian is concerned, they may also perform tests looking for heart disease or retinal degeneration. This may include chest x-rays, an echocardiogram (ultrasound of the heart), and a thorough eye exam.
Do dogs need taurine supplements?
The best way to reduce the risk of taurine deficiency for most dogs is to make sure that 90% of their daily calorie intake comes from a complete and balanced dog food (leaving some room for treats!).
These diets will have an AAFCO adequacy statement on the label, but ask your veterinarian if you’re unsure. Dog food that is formulated to meet the AAFCO standards contains the right levels of methionine and cystine, the essential amino acids your dog needs to make taurine.
The current recommendation from veterinary nutritionists is that taurine supplements should only be given to dogs diagnosed with taurine deficiency or DCM, and only as prescribed by a veterinarian.
For most dogs, a complete and balanced dog food will provide everything they need to produce enough taurine. However, certain large-breed dogs may be prone to developing taurine deficiency and associated diseases such as DCM for reasons we are yet to fully understand.
Speaking to your veterinarian or a veterinary nutritionist is the best way to alleviate your concerns and manage the risks for your dog.