Calcium Supplements & Absorption

Osteoporosis is a very common problem that leads to broken bones and poor posture in aging women and men.

To prevent the loss of bone mass, it is important to have sufficient calcium in the blood that is transported to the bones. Although calcium is abundant in dairy products like milk, the amount of calcium that we need increases as we age. Since many people quit eating or drinking food products with calcium, such as whole milk, due to a health-related diet, a dietary supplement with calcium is important. Older adults require approximately 1,200 milligrams of calcium per day. 

The remainder of this article addresses ways to get enough calcium to keep bones strong. The healthiest sources of calcium are from foods that are rich in calcium, including most dairy products, cheeses, fortified orange juice and leafy green vegetables, which can provide at least 100 milligrams of calcium. A balanced diet provides most calcium needed by older adults. However, additional calcium must be ingested to reach a required 1,200 milligrams per day. The body can handle more than the minimum requirement of calcium. However, the body cannot manufacture calcium if too little is ingested.

Calcium Supplementation

All calcium ingested is not absorbed into the body. The small intestine, which is the part of the digestive system just beyond the stomach, is where calcium is taken by the blood and transported to bone and other tissues. The amount of calcium absorbed is dependent on several key factors:

  • Amount of calcium already in the blood
  • Form of calcium (diet or formulation)
  • Small intestine conditions

Calcium typically comes as a liquid or tablet carbonate or citric acid preparation. The carbonate requires acid in the intestine that generally is generated with food in the stomach. Therefore, carbonate pills should be taken with meals by people taking calcium to increase calcium absorption. Calcium citrate is soluble and does not require meals for absorption. Most commonly used calcium supplements come as a carbonate form and should be taken during or immediately after meals. Check the label of your calcium supplement to determine which form you have and when to take it. 

Approximately 500 milligrams of calcium can be taken at one time. Therefore, do not take all supplements at the same time. If you and your doctor have agreed you need supplementation, be sure to take it three times a day or approximately one-third at a time. To avoid taking too much, do not take more than 2,500 milligrams per day.

Vitamin D also is required for calcium absorption. The best source of vitamin D is sunshine for approximately 20 minutes per day, which is not a problem for most people who live in the South. Vitamin D also is found in many other sources and generally is not responsible for poor calcium absorption. On the other hand, estrogen facilitates calcium absorption. After menopause, some women lose their ability to easily take up calcium. For this reason, calcium generally is given at menopause as a vitamin supplement.

The Bottom Line

As we age, we need calcium to prevent weak bones and fractures. Both women and men should take an additional 1,000 to 1,500 milligrams a day after first consulting a physician. Three doses of 500 milligrams of calcium should be taken each day, preferably with a meal, for healthier bones and other tissues.