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What are the risks of taking calcium?

  • Side effects. At normal doses, calcium supplements may cause bloating, gas, and constipation. Very high doses of calcium can cause kidney stones. Research in 2010 found an increased risk of heart attacks and strokes in some people taking calcium supplements in addition to a diet high in calcium, though the true accuracy of these findings is being actively debated by experts.
  • Interactions. If you take any prescription or over-the-counter medicines regularly, ask your doctor if it's safe to use calcium supplements. Calcium can interact with drugs for heart disease, diabetes, epilepsy, and other conditions. Excessive doses of vitamin D can result in dangerously high levels of calcium. High doses of calcium can also interfere with the absorption of other minerals, like iron and zinc. In general, take calcium one to two hours apart from other supplements or medications. When taken at the same time, calcium can bind those products and pass them unabsorbed from the body.
  • Risks. People with kidney disease, heart problems, sarcoidosis, or bone tumors should not take calcium supplements unless their doctors suggest it.
  • Overdose. Excessive levels of calcium in the blood can cause nausea, dry mouth, abdominal pain, irregular heartbeat, confusion, and even death.

There is no need to use products identified as "coral calcium." Claims made that coral calcium is superior to regular calcium are unsubstantiated. Also, coral calcium products may contain dangerous amounts of lead.

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