Vitamins are said to be good for you. According to a new study from the University of Minnesota, however, that may not always be the case.

Researchers reviewed the cases of 38,000 women over a 19-year period and found that those who took supplements had about a 2.4 percent increased risk of death over those who didn't, which could be related to the compounds supplements contain -- compounds that can be toxic in higher amounts and have a detrimental effect on those who use them long-term.

Jaakko Mursu, an epidemiologist at the University of Minnesota School of Public Health, said, "We would advise people to reconsider whether they need to use supplements, and put more emphasis on a healthy diet instead."

A number of vitamins and minerals, including iron, magnesium, multivitamins and zinc, were identified as possible links to this increased risk. "We do know that most compounds are toxic in high amounts, and long-term use might predispose [a person] to detrimental outcomes," said Mursu.

However, because of the nature of the study there's no current way to pinpoint any specific causes for increased mortality.

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