Some vitamin and mineral supplements -- including iron and multivitamins -- are associated with a small increase in the risk of death in older women, researchers reported Monday in the Archives of Internal Medicine.
Their results, which came out of a two-decade study of nearly 40,000 women in Iowa, are part of a longstanding debate: Are dietary supplements beneficial or not?
Many experts consider taking extra vitamins and minerals unnecessary -- at least for most in the Western world, where eating a healthful diet is relatively easy. "We see little justification for the general and widespread use of dietary supplements," nutritionist Jaakko Mursu, of the University of Minnesota School of Public Health in Minneapolis and the University of Eastern Finland, wrote along with coauthors. An accompanying article in the Archives of Internal Medicine echoed the sentiment. An editor's note also argued that "less is more" when it comes to taking your vitamins.
But for at least a few people, supplements offer clear benefits.
- Vegetarian women of childbearing age, for instance, may need supplemental iron, said Bonnie Jortberg, a registered dietitian who teaches at the University of Colorado School of Medicine in Denver (and who said that she rarely advises clients to take supplements).
- Women who are pregnant or plan to become pregnant should take folic acid to prevent neural tube defects, Mursu said. Some people need to take vitamin D as well, he added.
- And calcium supplementation -- the only type found beneficial in the Archives of Internal Medicine study -- can slow the progress of osteoporosis, said Judy Stern, a professor of nutrition at UC Davis.
"I'm concerned that [the results] will be overgeneralized," said Duffy MacKay, a vice president of scientific and regulatory affairs at the Council for Responsible Nutrition, an industry group that represents supplement makers, of the Archives of Internal Medicine study. Because the work was based on questionnaires and statistical analysis, he argued, people shouldn't draw strong conclusions from it.