Some sports supplements contain the ingredient DMAA. The FDA has warned that DMAA may not be safe. iStockphoto.com hide caption

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Despite public health campaigns urging women in the U.S. to take folic acid, many are still not taking the supplements when they become pregnant. iStockphoto.com hide caption

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There might be much more caffeine than you think in those supplements you're taking. There also might be much less. Janine Lamontagne/iStockphoto hide caption

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Federal health officials recommend 1,000 milligrams of calcium per day for people younger than 50, but some are overdoing it. iStockphoto.com hide caption

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Staying fit and eating well can help cancer survivors, too, a review of the latest evidence shows. Lucy Pemoni/AP hide caption

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