The American Dietetic Association provides the following information on vitamin and mineral supplements.
Food is the ideal source of nutrients.
The quality and variety of food in the U.S. allows nearly everyone to obtain an adequate and nutritious diet. Our food supply provides a unique balance which cannot be duplicated by a combination of vitamin and mineral supplements. Most healthy people don't need vitamin or mineral supplements. Taking more nutrients than your body needs won't provide added energy, more brain power, or protection against disease. Women with excessive menstrual bleeding may need to take iron supplements.