The Role of Taurine
Taurine is necessary for the normal development of most mammalian tissues and, in cats, is essential for normal vision, heart function and optimal reproductive performance. Low circulating blood levels of taurine – from inadequate dietary intake - can cause a number of reproductive abnormalities, including abortion, reabsorption of fetuses, low birth rates and fading kittens. Feline diets that are deficient in taurine can lead to Feline Central Retinal Degeneration (FCRD), which involves the irreversible and progressive degeneration of the retinal photoreceptor cells. FCRD eventually causes affected cats to go blind.
Insufficient dietary taurine can also cause cats to develop a serious and potentially fatal heart condition called dilated cardiomyopathy, also known as “DCM.” Research has shown that feline dilated cardiomyopathy may be completely reversible if the diet of affected cats is supplemented with 0.5 grams of taurine per day. The effect of low dietary taurine on heart health, retinal health and reproductive ability in companion animals other than cats has not been well-reported in the literature, probably because most domestic mammals, including dogs, are able to synthesize taurine fairly well. The number of cases of dilated cardiomyopathy has decreased dramatically in recent years, due to the addition of adequate amounts of taurine in high-quality commercial cat foods. Unfortunately, DCM is still occasionally seen in cats that are fed dog food (which does not need to be fortified with taurine), and in those fed home-made diets that are cereal-based rather than meat-based. Many home-made diets, but not all of them, have other nutritional deficiencies or imbalances, as well.
Most manufacturers have increased the levels of taurine in both canned and dry feline food products over the past 20 years. While recommendations vary as to what is the optimal level of taurine that should be in cat food, current thought is that dry cat food should have a minimum of 1000 mg/kg of taurine, and canned cat food should have at least 2000 mg/kg of taurine. Taurine is only present in animal tissue. It is found in the highest concentration in meat, poultry and fish – especially shellfish.
Causes of Taurine Deficiency
Unlike most other mammals, cats cannot produce the amount of taurine their body needs using building blocks from other dietary nutrients. Instead, cats must obtain this nutrient directly from their diet. As taurine has been added to commercial cat foods since the 1970’s, taurine deficiency is now usually only diagnosed in cats which are fed diets consisting of home cooked meals or dog food.
Cats in the wild, or stray cats, usually do not develop taurine deficiency because they are able to obtain the nutrient from eating smaller mammals.
Outlook for Cats with Taurine Deficiency
The outlook for taurine deficiency is usually excellent as long as the condition was treated in a timely manner. While irreversible blindness may occur from this condition, cats can still lead a long and healthy life after they have been successfully treated for taurine deficiency. Once cats are fed the proper diet, this condition will not return.