Hi Chacon. I have written repeatedly on this site about the "junk food of vitamins" - Centrum.
Read the label. Sugar is the leading ingredient (in about 5 different forms!). Additives, food colorings and preservatives are also major ingredients. You body has to detoxify these chemicals - a process that actually CONSUMES vitamins!
The minerals are in the cheapest available forms (oxides) which have been shown to be poorly absorbed (in some cases not absorbed at all!).
Another negative - Vitamin E is the synthetic form.
David Perlmutter, M.D. is a nationally recognized Neurologist and expert in nutritional treatment and prevention of chronic neurological diseases. He is a recent recipient of the Linus Pauling Award in medicine. As a guest lecturer at a large medical conference he said this about Centrum: "Centrum doesn't have enough nutrients in it for a gerbil!".
You are wise to consider taking a multivitamin/mineral supplement. Even the Journal of the American Medical Association (June 19, 2002) has recommended that you do so. The key is to take a quality supplement that will actually do you some good.
Talk to your family Chiropractor, Naturopathic Physician, or licensed Nutritionist for a recommendation. Or, try your local health food store. A good supplement will cost about $1 per day ($30 for a one month supply). However, price does NOT guarantee quality. But, cheap guarantees cheap!
Best wishes and good luck.