The short answer is YES! Most pet multivitamins are designed to contain a small portion of the daily requirement needed for a cat or dog, typically about 20 percent, whereas human supplements can contain 100 percent of the daily requirement. This means that if your pet consumes a human vitamin they can potentially receive an unhealthy excess of a particular vitamin or mineral.
Some vitamins can be toxic to pets, for example pregnancy supplements which are high in iron and can cause iron toxicity in pets. Similarly, too much vitamin D can increase levels of calcium and phosphorus, which can eventually lead to permanent problems with the heart and kidneys, among other organs. So if your pet happens to digest any vitamins lying around please call your vet immediately and make sure to take the vitamin bottle or box with you as the vet will be able to treat your cat or dog more quickly if they have all the information about dosage and ingredients.
So human vitamins can be dangerous for pets, however, you are not alone if are always thinking about your pet’s nutrition and it’s worth noting that most pet foods provide dogs and cats with the nutritional balance they need, rendering supplements unnecessary.
It’s always important to read your pets food packaging to make sure that their diet is packed with the appropriate amount of essential vitamins and minerals, this happens to be the easiest ways to both prevent and combat many medical problems. There are circumstances or exceptions that can occur in cases where your pet has a very low metabolism and requires dramatic food reduction in order to prevent weight gain. If, like myself, you end up reducing the calories in a balanced diet too much, the other nutrients will be reduced as well, potentially creating nutritional deficiencies. Pet-grade multivitamin or mineral supplement can help make up the difference.