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Taking Dietary Supplements? Don't Overdo It

plate of vitamin supplements

Older adults who take dietary supplements to boost their intake of minerals need to be careful they don't get too much of a good thing.

As reported in Reuters, a new study by the National Institutes of Health found that vitamin-users may be overloading on minerals, like iron, magnesium and zinc, that could cause health problems.

The study of 8,860 men and women found that people who take dietary supplements also tend to eat healthier diets and get more nutrients from their food than those who don't take supplements.

The result is that supplement-users often exceed the recommended daily amount of minerals between what they get from supplements and what they get in their daily diet. In others words, the people who take vitamins may be the people who need them the least.

Researchers are most concerned about are calcium and iron levels.

Too much iron can cause serious health problems, including liver damage. Men over age 19 and women over age 51 only need 8 mg. of iron daily.

As for calcium intake, older people were much more likely to fall short of their daily calcium requirement -- but also to exceed it, the study found.

That's because people tend to use more supplements as they age, which helps explain why nearly 16 percent of women between the ages of 51 and 70 reported daily calcium intakes that exceeded the recommended upper limit. Too much supplemental calcium has been linked to kidney stones.

In all, roughly a quarter of supplement users, and 71 percent of nonusers, did not receive the recommended daily amount of calcium -- 800 to 1,000 mg. a day for men over age 51 and 1,000 to 1,200 mg. daily for women of the same age. Adequate calcium is necessary for the health formation of bone.

"We always would hope that the people who are taking dietary supplements are the ones who need it the most, but it doesn't seem to be true," Cheryl Rock, a nutrition researcher at the University of California, San Diego, told Reuters.

Photo credit: Nicholas Eveleigh/Getty Images

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