Fat soluble vitamins are vitamins A, D, E, and K. Water soluble vitamins include vitamin C and the B vitamins. The addition of Fat soluble vitamins in a supplemental form can have a powerful and helpful effect in the body. As an example, vitamins D and K have essential roles in bone strength and when taken in the recommended amounts, they help to decrease fall risk. When consuming fat soluble vitamins, it is important to understand that they are stored in your body for longer periods of time than water soluble vitamins and have a greater potential to lead to toxicity when taken in excess. Toxic levels of a fat soluble vitamin can have negative effects which is why it is essential to test your Vitamin D when you are consuming it.