Daily Dose: Which Vitamins Help, Harm?

May 1, 2006 — -- It's become a daily ritual -- taking pills to supplement the vitamins, minerals and enzymes in your diet.

Americans spend nearly $9 billon every year on vitamin and mineral supplements in the belief that they can help prevent disease and improve health.

No one questions the value of a daily multivitamin, and yet some experts say additional supplements are unnecessary, and in some cases may be dangerous.

For example:

Even calcium, which is encouraged in large amounts as women get older, can be dangerous. The Women's Health Initiative, though it found calcium and vitamin D can lower the risk of hip fractures in women over 60, also found that women taking calcium were at a higher risk for kidney stones.

One woman we spoke with, Arlene Freedman, was taking calcium supplements while also eating a diet rich in calcium. Then a routine blood test revealed all these sources of calcium were too much .