A large study of midwestern women found that several vitamin and mineral supplements were associated with an increased rate of death over 20 years. The Iowa Women’s Health Study included almost 40,000 women over 60. About two-thirds of them used at least one dietary supplement daily at the beginning of the study. By the end, approximately 85 percent were taking at least one supplement.
Most women take vitamins or minerals because they assume the pills will improve their health, but the researchers found that multi-vitamins, vitamin B6, folic acid, iron and some other minerals were all associated with higher death rates compared to women who were not taking them. Somewhat surprisingly, calcium was associated with a lower death rate. Calcium supplements have recently come under scrutiny because of an association with heart disease, but this study did not find a connection. Supplemental iron, on the other hand, was associated with higher mortality.
