Cats require both vitamin A and niacin in their diet. These vitamins are found in animal tissues and again, their requirement makes the cat a truly carnivous animal. Because cats have different requirements for the levels of vitamins in their diets, they should not be fed dog food or vegetarian diets . Vitamin deficiencies are rarely a problem in healthy cats eating a wholesome diet. Deficiencies occur if a cat is fed a poorly formulated diet or food that is improperly stored or preserved.
Vitamins are subject to rapid degradation in high temperatures during the cooking process.
This is most often the case with generic or very inexpensive cat foods and with home cooked diets. Improperly processed fish cat foods may also contain a substance that destroys the B vitamin called thiamine. In the most severe form of thiamine deficiency, cats can develop depression and seizures . Some disease conditions can result in a vitamin depletion. Because fat-soluble vitamins are in reserve, problems related to deficiencies in these vitamins usually occur after a longer period of time.