There ar many millions of people out there taking high dose vitamin pills daily, especially beta carotene and vitamins C and E, the antoxidant nutrients that they recieved has gotten so much media attention in recent years. But these supplements are really no substitute for plain old good eating habits, and the majority of these people can fill their nutrition needs by following a good diet regimine.
These megadose vitamins can actually be harmful. When taken in very large amounts, vitamins and minerals, like all drugs carry the risk of adverse side effects and interactions. Many minerals, and vitamins A and D are stored in the body and can build to toxic levels when taken in large doses. The presence of large quantities of a particular vitamin or mineral in the intestinal tract invariably interferes with the body's ability to absorbtion of other nutrients and can lead to deficiency diseases.
Where supplements are needed, they should only be prescribed by a doctor. For example a woman planning to concieve or who is already pregnant needs extra folate to protect the baby from neurological problems. Pregnancy also increases the demand for iron beyond what can be obtained from an ordinary diet. An older woman may need additional calcium and vitamin D to help prevent Osteoporosis.