The risks of supplements

The new study isn't the first to link supplement use with harmful effects. In 2011, a large study found that use of vitamine E and increase of prostate cancer in men. Also that year, a separate study among older women found that use of supplements was linked to increase rate of death during the 20-year study period.

Nutrition experts recommends that people try to get their nutrients from foods by eating a healthy diet that includes nutrient-dense foods. The academy points out that foods can contain beneficial components that aren't found supplements, such as fiber or bioactive compounds.

"Real food contains healthy things a pill can't give us," the academy says. "When we take a nutrient out of a food and concentrate it in a pill, it's not quite the same thing."

Still, people with certain diseases or conditions may not be able to get all the nutrients they need from food, and thus might need to take a supplement. For example, pregnant women often need to take folic acid or iron supplements to prevent birth defects and help the growing fetus. People with certain food allergies or digestive conditions may also need to take supplements.