• The basics of bone
  • Bone remodeling
  • Peak bone mass
• What causes osteoporosis?
  • Primary osteoporosis
  • Secondary osteoporosis
• Who gets osteoporosis?
  • Osteoporosis risk in women
  • Osteoporosis risk in men
• The consequences of osteoporosis
• Hip fractures
  • Spinal fractures
  • Wrist fractures
  • Other consequences
• Detecting osteoporosis
• Protecting your bones
  • Calcium
  • Vitamin D
  • Bisphosphonates
  • Raloxifene (Evista)
  • Hormone therapy
  • Calcitonin
  • Parathyroid hormone
• Exercise: Your not-so-secret weapon for good bone health
  • How exercise benefits bones
  • Starting a strength training program
  • Balance exercises to try
• Preventing falls
  • 10 ways to prevent falls
• Developing a plan of action
  • An early start
  • Women in early postmenopause
  • If you are 65 or older
• Coping with fractures
  • Living with vertebral fractures
  • Living with a hip fracture
  • Support groups
• Sources of calcium
  • Dietary calcium
  • Calcium supplements
• Resources
• Glossary

Calcium supplements

While experts recommend getting your nutrients from foods instead of supplements, you may find that it just isn’t practical or possible for you to get all the calcium you need from your diet. In that case, a supplement can shore up your calcium intake and your bones. In fact, a 2002 analysis of several studies of postmenopausal women found that the women who took calcium and vitamin D supplements for at least two years were 23% less likely to suffer a spinal fracture.

A dizzying array of calcium supplements is available—so many, in fact, that choosing one can be tricky (see Table 6). You can choose from flavored chews, pills, chewable tablets, and liquids. When making a decision, it’s wise to consider cost, convenience, and how well your body tolerates the supplement.

The calcium in supplements is found in combination with another substance, typically carbonate or citrate. (Some products combine calcium with phosphate, lactate, or gluconate, but these are less common and tend to be more expensive.)

Calcium carbonate tends to be the best value, because it has the highest amount of elemental calcium. Elemental calcium is the actual amount of calcium in each supplement. The compound calcium carbonate contains 40% calcium by weight, while calcium citrate is 21% calcium. This means that you may need to take more tablets of a calcium citrate product in order to meet your daily needs.

Because calcium carbonate requires stomach acid for absorption, it’s best to take this product with food. Most people tolerate calcium carbonate well. However, some people complain of mild constipation or feeling bloated. Some well-known calcium carbonate products include Caltrate, Viactiv Calcium Chews, Os-Cal, and Tums.

On the other hand, calcium citrate is absorbed more easily than calcium carbonate and can be taken on an empty stomach. But as mentioned above, you may need to take more tablets to get your daily requirement. Calcium citrate products include Citracal and GNC Calcimate Plus 800.

In weighing your options, check the labels of products to see what the serving size is and what the “% Daily Value” for calcium is. The “% Daily Value” reflects how much elemental calcium is in the product. The Daily Value is set by FDA regulations and is not the same as the Recommended Dietary Allowance (RDA). Currently, the Daily Value for calcium is 1,000 mg—the RDA for people ages 19 to 50, not the 1,200 mg RDA for older adults. Since the “% Daily Value” for all calcium supplements is 1,000 mg, simply multiply the percentage listed by 10 to find out how much elemental calcium the product contains. For example, if the label says the product contains 40% of the Daily Value, it has 400 mg of elemental calcium.

You’ll find that the serving size and “% Daily Value” vary from product to product. For example, one Viactiv Calcium Chew contains 500 mg of calcium, while two Tums E-X antacid tablets provide 600 mg. One company may offer several different supplements, with varying amounts of calcium (see Table 6). In addition, some supplements may include vitamin D while others don’t.

Reading the labels with an eye toward cost and convenience may help you sift through your options. Would you find it inconvenient to take several tablets at a time? How many tablets or chews does the package contain, how many must you take at a time, and what is your cost per serving? While products that yield a high amount of calcium may seem to be the best bet at first blush, they may not serve you best. Because your body has difficulty absorbing more than 500 mg of calcium at a time, more of the mineral may go to waste. So while you may think that you’ve met your daily requirements by taking that 1,000-mg calcium pill, you may actually be only halfway to your target.