Since we were young, our parents have told us that we need to eat a lot of fruit and vegetables if we want to be strong and healthy. For some of us, that stays true today as well. And just like us, dogs need vitamins in their diet to help them grow, develop, and stay healthy. That is why nowadays, there are a lot of companies that produce dog supplements, and all of them have pretty much the same purpose: to keep your dog healthy. But what vitamins do dogs need anyway?