Daily supplements come under fire for a lack of proved benefits and mounting evidence about risks.
Eating too much, rather than not enough, is the big health problem for most Americans. Yet, many of us take a supplement or vitamin in the hope of staving off illness with big doses of particular nutrients.
A new study shows that might not be such a great idea. Use of many common supplements — iron, in particular — appeared to increase the risk of dying, and only calcium supplements appeared to reduce mortality risk. The increased risk amounted to a few percentage points in most instances.
The findings come from a study of more than 38,000 older women in Iowa. In 1986, when the study got rolling, two-thirds of the women (average age 62) were taking a vitamin or supplement. By 2004, 85 percent were.
The bad news is that the findings went against so many of the supplemental nutrients — from multivitamins to zinc. Yes, it's true that the study's data came from people's own reports about what they took instead of randomizing treatment between supplements and a placebo.
Another study finds that vitamin E raises — rather than lowers — men's risk for prostate cancer.
Even so, the results are striking. "Although we cannot rule out benefits of supplements, such as improved quality of life, our study raises a concern regarding their long-term safety," the authors of the study write. Then, they say, "Based on existing evidence, we see little justification for the general and widespread use of dietary supplements." The study results appear in the latest issue of Archives of Internal Medicine.
And it's probably worth noting that calcium, which did relatively well in this study, has been problematic in other research, such as an analysis last year that found use an increased risk of heart trouble, but not deaths, in older women.
A commentary on the latest study says taking supplemental doses of nutrients beyond biological minimums is usually a mistake: "We think the paradigm 'more is better' is wrong."
Still want a nutritional supplement? Try the produce aisle instead.
"A better investment would be eating more fruits and vegetables," writes Dr. Rita Redberg, editor of the Archives of Internal Medicine. The journal put its "Less is More" label on the study because supplements haven't been shown to carry a mortality benefit and have been shown to increase various health risks.
Previously in the journal's "Less is More" series, five things primary care doctors should do less often to improve care and the case against narcotics as treatment for chronic pain.