Most vitamins that we consume are water soluble. That means that water is a catalyst that makes it possible for these vitamins to be used in the body.
The human body is mostly water and thus, water soluble vitamins will be “washed away” & eliminated regularly.
It’s not a problem as long as a healthy diet is eaten regularly. Eating a diet that contains a steady supply of color and bioflavonoids will usually prevent a deficiency.
When large doses are needed, supplements come in handy.