Spinach is a perfectly healthy food option for a dog. According to PawNation, spinach is rich in fiber, iron and potassium and calcium, which are all essential to a balanced diet.
Several commercial dog food brands offer food that contains spinach as well as other vegetables; however, there are several ways that dog owners can add spinach as a supplement to regular dog food. Modern Dog Magazine recommends finely chopping and steaming green, leafy vegetables and adding them to regular dog food. It is also possible to add spinach to homemade dog food to provide additional nutrition. For example, adding steamed spinach to meat and rice creates a fully balanced meal for a dog.