Supplements linked to death in older women.
Older women who use iron pills or some other common vitamin and mineral supplements daily might be at an increased risk of premature death compared with nonusers, while those who take calcium supplements might be at a decreased risk, researchers reported in the current issue of Archives of Internal Medicine.
The investigators analyzed data on dietary supplement use and mortality among 38,772 Iowan women who had an average age of 62 when the study began in 1986. After about 19 years of follow-up, women who took multivitamins or dietary supplements containing copper, folic acid, iron, magnesium, vitamin B6, or zinc were more likely to have died compared with women who had not taken supplements of those nutrients.
The association between daily supplement intake and mortality risk was strongest with iron. Moreover, as women aged, the risk of death was linked with progressively lower doses.
In contrast, women who took calcium supplements had slightly better survival rates, the researchers reported, though no clear dose—response relationship was found.
The study is large, and the researchers adjusted for such things as age, diet, health, hormone replacement therapy, and smoking. Still, it was an observational study, not clinical trial, so it’s possible that other factors contributed to the results, according to an accompanying editorial in the journal by researchers at the University of Nis, in Serbia, and Copenhagen University Hospital, in Denmark.
Bottom line: This new study raises concern about the long-term safety of some dietary supplements among older women, and echoes several other recent studies that reached similar conclusions. For example, while the current analysis suggests that women who take calcium might live slightly longer, another recent studylinked calcium supplements with increased risk of heart attack. We generally recommend supplemental vitamins for people who have clear deficiency. For other people, it’s best to get your nutrients from a varied, healthful diet that includes lots of fruits, vegetables, and whole grains.