When should I take calcium supplements? Does the timing matter?

Answers from Katherine Zeratsky, R.D., L.D.

Yes. Three factors determine when you should take calcium supplements:

  • The type of calcium. Check the label to find out what kind of calcium a supplement contains. If the supplement contains calcium citrate, you can take it with or without food. If the supplement contains calcium carbonate, take it with food. Stomach acid produced while eating helps the absorption of calcium carbonate.
  • The daily dose. Calcium is absorbed most efficiently when it's taken in amounts of 500 milligrams (mg) or less at one time. So if you take 1,000 mg of calcium a day, split it into two or more doses over the day.
  • If you take prescriptions. Calcium supplements can interact with many prescription medicines, including antibiotics, bisphosphonates and high blood pressure medications. Ask your doctor or pharmacist about possible interactions between calcium supplements and your medications.

It's also a good idea to take your calcium supplements at a different time from your multivitamin or an iron-rich meal. Calcium may not be absorbed as well if it's taken at the same time as iron, zinc or magnesium.

If you still aren't sure about the best time to take calcium supplements, check with your doctor or pharmacist for guidance.

Sep. 18, 2012 See more Expert Answers