Can Supplements Increase a Woman’s Risk of Dying?

Oct. 10, 2011 -- Some of the supplements that older women take to improve their health may actually raise their risk of death.

In a new study, multivitamins, folic acid, iron, copper, magnesium, zinc, and vitamin B6 supplements all increased an older woman’s risk of dying from any cause. The greatest risk was seen with iron supplements. Calcium supplements, however, seemed to reduce a woman’s risk of dying.

The study, which appears in the Archives of Internal Medicine, was an observational trial, not a cause-and-effect trial. So it can’t say how, or even if, these supplements actually increase a woman’s chance of dying.

By all counts, the dietary supplement industry is booming in the U.S. It grosses billions of dollars per year. A growing number of people are taking one or more vitamin, mineral, or herbal supplements in order to maintain or improve their health. Many also turn to these supplements to treat diseases or conditions.

Women who took part in the Iowa Women’s Health Study were aged an average of 61.6 in 1986. They answered questionnaires about their supplement use through their 80s. A total of 15,594 women died by the end of December 2008. More women took supplements as they aged, with 62.7% saying they took at least one supplement in 1986 and 85.1% saying they did so in 2004.

Women who took multivitamins, folic acid, vitamin B6, iron, copper, magnesium, and zinc supplements were more likely to die than women who did not take supplements even though they had healthier habits and lifestyles than women who did not supplement their diet with extra vitamins and minerals. Supplement use was likely not an indicator for failing health or disease onset.

Popular Supplements May Be Dangerous to Your Health

“It is a big story,” says researcher David R. Jacobs Jr., PhD. He is a Mayo Professor of Public Health in the division of epidemiology and community health at the University of Minnesota School of Public Health in Minneapolis.

Jacobs says the findings may also apply to women -- and men -- of all ages.

His theory is that supplements don’t have the same checks and balances as whole foods. Supplements provide a single nutrient in isolation and may be taken in high, potentially toxic doses. Whole foods are balanced with other nutrients.

Too much vitamin B6, for example, on its own may be harmful, but the foods that contain B6, such as avocados, bananas, dried beans, and whole grains, also bring other nutrients to the table that may all work together.

“People may eat well and take supplements for a guarantee, but this wisdom is not wise,” he says.

“Supplements are regarded as safe as they come from food, but they do have drug-like effects,” Jacobs says. “It would be wise to start treating these as if they are drugs and actually test them.” Supplements are not regulated by the FDA in the same manner as drugs in the U.S.

If you can get your nutrients from food, do that, he says. Elderly people who have issues cooking or eating may need supplements, but this should be done under the guidance of their doctor.

Jaakko Mursu, PhD, of the University of Eastern Finland in Kuopio, Finland, and the University of Minnesota, Minneapolis, is also an author on the study. “We would advise people to reconsider whether they need to use supplements and put more emphasis on a healthy diet,” he says in an email.