The difference between water soluble and fat soluble vitamins is that water soluble vitamins are dissolved in water and fat soluble vitamins are dissolved in fat globules or lipids. This difference determines how the vitamin acts in our bodies. Fat soluble vitamins travel through our body via the lymphatic system of the small intestine and then into our bloodstream. They are then stored in our body tissues. Water soluble vitamins are more easily absorbed into our bloodstream via the wall of the small intestine.