Taurine is an amino acid that cats cannot synthesize in adequate amounts and must obtain from diet. Taurine deficiency in cats causes feline central retinal degeneration (irreversible blindness) and dilated cardiomyopathy. Dogs synthesize their own taurine but some breeds and some grain-free formulations show lower-than-expected taurine levels, possibly contributing to DCM. All AAFCO-compliant cat foods are taurine-supplemented; many quality dog foods are too.