But ABC's chief health and medical editor, Dr. Richard Besser, is telling women not to throw out their multi-vitamins just yet.
"This was a study of women in Iowa and it looked at the risk of dying for women who took a multivitamin. The risk of dying increased by a little over 2% if they were taking a multivitamin and increased by 3% of they were taking iron. Very concerning but I think this study is being a over-interpreted," Besser said.
After looking over the controversial study, Dr. Besser says it's more important to find out if you really need to take a vitamin.
Supplements are a $27 billion a year business, and Dr. Besser says many people are swallowing a pill without a lot of power.
"We all need vitamins," Besser said. "The question is, do we need additional vitamins and supplements? I wouldn't take away much from this study. There's been a lot of work looking at vitamins over the years and really, it's hard to say there's a real benefit but I think there's very little to suggest taking a multi-vitamin is harmful. Women who are doing that, I think should continue to do that if they feel comfortable taking that multivitamin."
Dr. Besser recommends looking at your diet before taking any vitamin. If you're lacking in a certain food group a supplement might help fill in the gap.
Yet while the possible risk of vitamins continues to be studied, Dr. Besser's advice to women on vitamins is don't take it if you really don't need it.