It is known that many people are deficient in some minerals and vitamins, and I've included information on such deficiencies when I'm aware of it.  Taking a multivitamin-mineral supplement was helpful.  As far as I know, the following was based on people who ate typical western diets (USA Weekend 11/21/03 p.6).


There are four fat-soluble vitamins, A, D, E, and K.  They can be stored in fatty tissue, making overdose easier.  Removal of the gall bladder can make absorption of A, D, E, and K difficult.  Take them with food containing oil or in gel cap form.
The remaining vitamins (mainly B and C) are water soluble and eliminated rather quickly.  Thus overdosing is difficult and the vitamins should be consumed (food and/or supplement) on a nearly daily basis.

Some National Academy of Sciences intake recommendations.