Fat soluble vitamins are different from water soluble vitamins as fat soluble vitamins can be stored in the body for long periods of time in the fat cells and can cause / lead to toxicity when consumed in excess. Fat soluble vitamins also need fat in food for their absorption into the blood stream from food during digestion. Excess intake of water soluble vitamins is not harmful as the excess vitamins that are not required flow out of the body through urine.