Taurine is an essential nutrient for cats, because, unlike dogs for instance, cats cannot make their own taurine from amino acids (the building blocks of proteins). That’s why it is essential for cats to get this nutrient from their food. A chronic taurine deficiency in cats can cause problems in the retina, resulting in blindness, or even ultimately result in heart disease, among other ailments. Animal proteins are a source of taurine.