There is much debate over which type of calcium supplement, calcium carbonate or calcium citrate, is absorbed the best. Use the tips to help make your choice easier. Your doctor will also help you make your decision.

• Take no more than 500-600 milligrams (mg) of calcium at one time. Once calcium intake gets higher than that, absorption begins to decrease. Consider how much you are getting with your food. If you eat a high calcium breakfast, such as cereal with milk or calcium-fortified orange juice, you may want to save your calcium supplement for later.
• Both calcium citrate and calcium carbonate are absorbed well.
• Calcium carbonate requires stomach acid for adequate absorption. Take calcium carbonate with food, because the stomach produces acid when you eat.
• Because calcium citrate does not require stomach acid for adequate absorption, it can be taken without food.
• Take calcium citrate if you are taking a strong prescription antacid, like Nexium, Prilosec, or Axid.
• If you are taking an iron supplement, you should take calcium citrate.