Osteoporosis and Calcium: How to Choose a Supplement

Osteoporosis and Calcium

Calcium can help prevent and treat osteoporosis. What type is best for you?

ou’ve heard that taking a calcium supplement can help prevent and treat osteoporosis. But do you know what type to take, when to take it and how much you need? Getting these questions answered can help you maximize the benefits.


Ten million Americans – most of them women – suffer from osteoporosis. When you don’t get enough calcium, your bones can become brittle and break easily. Osteoporosis accounts for 1.5 million fractures each year.

The key to osteoporosis prevention is to get plenty of milk, yogurt and other foods that contain low-fat calcium in your diet. If you aren’t getting enough calcium, supplements can help fill in the gap.

Two forms of calcium

There are two kinds of calcium supplements: calcium carbonate and calcium citrate.

Calcium carbonate
Brands of calcium carbonate include Tums, Rolaids, Os-Cal, Viactive and Caltrate. Calcium carbonate is:

  • Inexpensive
  • Convenient
  • Contains twice as much calcium per pill as calcium citrate
  • Best absorbed by taking after meals or with orange juice

Calcium citrate
Brand names include Citracal and Solgar. Calcium citrate:

  • Is easily absorbed
  • Can be taken any time of day
  • May need to be taken more than once a day because it has less calcium per pill than calcium carbonate

How much calcium do you need?

People between the ages of 19 and 50 should get 1,000 mg of calcium per day. After age 50, your body requires 1,200 mg. When taking calcium supplements, keep these things in mind:

  • Because your body cannot absorb more than 500 mg of calcium at a time, spread your doses out throughout the day.
  • If you have a calcium-containing food with a meal, take your calcium later.
  • If you take iron, do not take it at the same time as your calcium supplement. It interferes with calcium absorption.

Add vitamin D

Vitamin D helps your body absorb calcium. Some people can get enough vitamin D in their normal exposure to sunlight each day. But vitamin D deficiency is common after the age of 50. That’s because we make less vitamin D as we age and it’s hard to get enough of it in our diets.

If you normally wear sunscreen or live in higher latitudes, you may not be getting enough vitamin D. People also get less vitamin D during the winter months, when the days are short and cold. According to the National Institutes of Health, adequate vitamin D intake is 400 IU for healthy people ages 51 through 70. Healthy adults aged 71 and over should strive for 600 IU daily. People with thinning of the bones, osteoporosis or who are frail or housebound may need up to 800 IU.

The guidelines of the National Osteoporosis Foundation are slightly higher. They say that adults age 50 and older should get 800 IU to 1,000 IU of vitamin D each day.

If you do not feel that you are getting enough vitamin D, ask your doctor about a supplement that combines calcium and vitamin D.

Who should not take calcium supplements?

If you take certain prescription or over-the-counter medications, they may interact with calcium. Some of these medications are:

  • Tetracycline
  • Some laxatives
  • Antacids that contain aluminum or magnesium
  • Thiazide
  • Digoxin
  • Certain anticonvulsants

If you take any of these medications, or if you have hypothyroidism, a low serum phosphate level or a high serum calcium level, talk to your doctor before taking any calcium supplements.

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