Feeding your dog the correct diet is not just about giving them a shiny coat and fresh breath. Food is made up of essential micronutrients that your dogs need to be healthy. Suppose your dog receives a poor nutrient balance – in that case, they are more likely to suffer from many health conditions, some of which can be very serious. But don’t panic just yet. Most poor diets need to be fed for a long time before they can do any harm. This article will discuss the importance of two essential food components, taurine and carnitine. It’s important to check that your dog is receiving the correct nutrients and, if not, understand the best action to take. As pet owners, diet is one of our greatest tools for ensuring a healthy and happy dog!
What is taurine?
Taurine is an amino acid, a building block that makes important proteins in the body. Taurine is abundant in meat and can be obtained directly from the diet. Cats, however, are unusual as they cannot synthesise taurine themselves, and they rely on it being available in its original form in their food. Commercial cat foods are regulated to ensure that taurine levels are adequate. In contrast, dogs can transform other sulphur-containing amino acids, such as methionine and cysteine, into taurine. This sounds like great news for our canines. But, on the flip side, it can be much harder to determine whether our dog is producing enough taurine – although they can make it, they aren’t very efficient at doing so. And the specific amino acid levels in their diets are not being so closely regulated as in cat foods.
All amino acids contribute to the healthy functioning of the body. In the case of taurine, it is critical in many life-sustaining processes. Body systems relying on taurine include the muscles of the skeleton, the central nervous system, and the production of bile which allows fat to be digested. However, more notably, taurine is essential in building heart muscle. It influences calcium levels inside cells which affects the heartbeat, and it functions as an antioxidant which can protect the heart. Pretty impressive, really!
What is carnitine?
Like taurine, carnitine can be synthesised from other amino acids. Carnitine is also known as L-carnitine or levocarnitine. Carnitine also exists in different forms when the molecule is a slightly different shape (e.g. D-carnitine). However, this isomer is less valuable to the body. Carnitine is crucial in helping cells make energy within mitochondria – tiny ‘energy factories’ found within each cell of the body. Carnitine also assists in the removal of toxic products from these mitochondria. Because producing energy is the key function of carnitine, it is concentrated at high levels in muscle cells. It is vital in producing the heart’s energy to contract and beat.
Why do I need to give my dog taurine and carnitine?
There is mounting evidence that taurine and carnitine deficiencies can lead to dilated cardiomyopathy in dogs (DCM). DCM is a serious condition where the heart’s chambers dilate and become bigger. In doing so, the cardiac muscle wall becomes thinner and more floppy. This impairs the heart’s ability to contract and pump blood around the body. This irreversible change in the heart can lead to life-threatening heart disease and ultimately heart failure, arrhythmias and sudden cardiac arrest. However, more research is needed in this field to determine exactly why this occurs and at what degree of deficiency.
There are, of course, other causes of DCM, breed predisposition being the most widely documented. It is particularly prevalent in Doberman pinschers and Irish wolfhounds. In addition, DCM may occur secondary to other medical conditions. For example, hypothyroidism, heart rhythm disturbances and myocarditis (inflammatory heart muscle disease) can lead to DCM.
DCM is a worrying disease due to its silent nature. Often there are no symptoms until the patient becomes critically ill or collapses. This is why heart screening programs are commonly offered to dogs known to be at-risk breeds. Investigations typically involve a specialist heart scan (echocardiogram/echo) and an ECG. In cases of greater concern, your dog might be fitted with a 24-hour Holter monitor, which detects any abnormal cardiac rhythms.
What are the best sources of taurine and carnitine?
Whilst we know that taurine and carnitine both contribute to heart health, it is still unclear what role diet plays in this. Of course, diets containing higher meat protein content are likely to have higher levels of taurine and carnitine. But, as with all commercial products, labelling can be confusing. Read more about pet food manufacturing and labelling here. There is a common belief that grain-free diets and those high in novel protein sources can contribute to the development of DCM. Veterinary cardiologists and researchers are encouraging the public to move towards grain-based diets containing traditional protein sources. However, evidence in this field is still conflicting. Vegan diets are of genuine interest as they grow in popularity. One short-term study showed no ill effects of feeding lentil-based proteins, but long-term reliable and objective data are unavailable.
Why do some dogs become deficient?
The reason that dogs suffer from taurine and carnitine deficiency is complex. It’s not just down to what they eat, but rather a series of intricate interactions between their diet and body. Here are some ways that we believe dogs become deficient in these nutrients:
- High fibre diets, conditions affecting the intestine and any other reason for increased pooping may decrease the absorption of amino acids from food.
- Different cooking processes may affect taurine levels in food: boiling appears to destroy it, whereas other cooking methods do not.
- Grain-free diets may be low in sulphur-containing amino acids and more likely to contain higher levels of plant-based proteins.
- Plant-based protein diets are likely to contain less taurine and carnitine AND fewer sulphur-containing amino acids. This is not regulated in commercial dog foods.
- Giant and large dog breeds may struggle to obtain enough taurine, carnitine and other amino acids from their food due to their lower energy requirements despite their high body weight.
We still have a lot to learn regarding taurine, carnitine, and diet’s effects on our dog’s health. Further prospective studies are essential so that we can understand what diets present a risk to our pets. As more information becomes available, it will be easier to make the best lifestyle choices to keep our dogs in tip-top condition.
- McCauley SR, Clark SD, Quest BW, Streeter RM, Oxford EM. (2020). Review of canine dilated cardiomyopathy in the wake of diet-associated concerns. Journal of Animal Science, 98(6). [Accessed 27 September 2022]
- Pezzali JG, Acuff HL, Henry W, Alexander C, Swanson KS, Aldrich CG. (2020). Effects of different carbohydrate sources on taurine status in healthy Beagle dogs. Journal of Animal Science, 98(2). [Accessed 27 September 2022]
- Reilly LM, He F, Clark L, de Godoy MRC. (2021) Longitudinal assessment of taurine and amino acid concentrations in dogs fed a green lentil diet. Journal of Animal Science, 99(11). [Accessed 27 September 2022]
- Canine Dilated Cardiomyopathy (DCM) – Cornell University College of Veterinary Medicine [Accessed 27 September 2022]
- Pet Food Manufacturers Association [Accessed 27 September 2022]