Calcium Supplements: Buyer's Guide


Adequate calcium intake is important because the body loses calcium every day through the skin, nails, hair, and sweat, as well as through urine and feces.

This lost calcium must be replaced daily through the diet. Otherwise, the body takes calcium out of the bones to perform other functions, impacting senior bone health by making bones weaker and more likely to break over time. This condition is known as osteoporosis.

Experts recommend that adults get 1,000 to 1,200 mg (milligrams) of calcium each day. Although food is the best source of calcium, most Americans do not get enough of it from food sources. Calcium-fortified foods (like orange juice, bread, cereals, and many others on your grocer's shelves) and calcium supplements can fill the gap.

What Calcium Does for the Body

This mineral plays a vital role in:

  • Regulating the heartbeat
  • Conducting nerve impulses
  • Stimulating hormone secretions
  • Clotting of blood
  • Building and maintaining healthy bones

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Choosing the Right Calcium Supplement

Many people ask which calcium supplement they should take. The "best" supplement is the one that meets your needs. Ask yourself to questions below to help you narrow down your options.

  • How well does my loved one's body tolerate this kind of supplement? Does it cause any side effects (like gas or constipation)? If so, you may want to try another kind or a different brand.
  • Is this kind of supplement convenient? Can my loved one remember to take it as often as recommended each day?
  • Is the cost of this supplement within my loved one's budget?
  • Is it widely available? Can my loved one buy it at a store near her?

What to Look For in Calcium Supplements

When purchasing calcium supplements to ward off osteoporosis, there are a few important qualities to look for.

  1. Purity
    Choose calcium supplements with familiar brand names. Look for labels that state "purified" or have the USP (United States Pharmacopeia) symbol. Avoid calcium from unrefined oyster shell, bone meal, or dolomite without the USP symbol, because it may contain high levels of lead or other toxic metals.
  2. Absorbability
    Most brand-name calcium products are absorbed easily in the body. If you are not sure about your product, you can find out how well it dissolves by placing it in a small amount of warm water for 30 minutes and stirring it occasionally. If it hasn't dissolved within this time, it probably will not dissolve in your stomach. Chewable and liquid calcium supplements dissolve well because they are broken down before they enter the stomach.
    Calcium, whether from food or supplements, is absorbed best by the body when it is taken several times a day in amounts of 500 mg or less, but taking it all at once is better than not taking it at all. Calcium carbonate is absorbed best when taken with food. Calcium citrate can be taken anytime.
  3. Tolerance
    For certain people, some calcium supplements may cause side effects such as gas or constipation. If simple measures (such as increasing your intake of fluids and high-fiber foods) do not solve the problem, you should try another form of calcium. Also, it is important to increase the dose of your supplement gradually: take just 500 mg a day for a week, then slowly add more calcium. Do not take more than the recommended amount of calcium without your doctor's approval.
  4. Combination Products
    Calcium supplements are available in a bewildering array of combinations with vitamins and other minerals. Calcium supplements often come in combination with vitamin D, which is necessary for the absorption of calcium. However, calcium and vitamin D do not need to be taken together and/or in the same preparation in order to be absorbed by the body. Minerals such as magnesium and phosphorus also are important but usually are obtained through food or multivitamins. Most experts recommend that nutrients come from a balanced diet, with multivitamins used to supplement dietary deficiencies.

Beware of Calcium Interactions

It is important to talk with a doctor or pharmacist about possible interactions between your medications (both over-the-counter and prescription), and calcium supplements. For example, calcium supplements may reduce the absorption of the antibiotic tetracycline. Calcium also interferes with iron absorption. So your loved one should not take a calcium supplement at the same time as an iron supplement - unless the calcium supplement is calcium citrate, or unless the iron supplement is taken with vitamin C. Any medication that you need to take on an empty stomach should not be taken with calcium supplements.

Getting enough calcium, whether through diet or with the help of supplements,will help to protect the health of your loved one's bones. However, this is only one of the steps you need to take for bone health. Exercise, a healthy lifestyle, and, for some people, medication, are also important.

Source: The National Institutes of Health (NIH),

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