Young People Get Osteoporosis Too 

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In regards to which  form of calcium supplement is best, It makes little practical difference, as long as you take enough. Read the labels: check the milligrams of "elemental calcium" you're getting per pill, not the amount of calcium gluconate, for instance, or calcium citrate. No pill is pure calcium. The mineral has to be combined with something else: carbonate, citrate, gluconate, etc. Plain calcium carbonate, as found in some antacids, is most common and least expensive, and contains the highest concentration of calcium per pill. Thus, to get a given amount of calcium, you can take smaller pills, or fewer of them. Recommendations for how much calcium you need are in terms of elemental calcium, so read labels carefully to make sure that you are getting what is recommended.


How do I choose a calcium supplement?

  • A USP (United States Pharmacopeia) symbol means that the calcium supplement is pure from lead and other metals. The application for the USP symbol is voluntary so many acceptable products do not display this symbol. According to a recent laboratory analysis, calcium supplements, in the dosage prescribed for prevention and treatment of osteoporosis, contain much less than the safe level of lead. A further safeguard is that lead in calcium supplements will not be well absorbed because calcium blocks lead absorption.
  • Calcium must dissolve in your stomach before it can be absorbed in your intestines and then used by your body. A USP symbol on the label of a calcium supplement means that is it will dissolve in your stomach. If your supplement does not have a USP symbol, you can easily test it to find out if it will dissolve. Simply put the supplement into a glass of clear vinegar. This creates an acidic environment much like that of your stomach. Stir the solution occasionally. If the calcium supplement disintegrates within 30 minutes, it should dissolve in your stomach, too. If the supplement does not completely dissolve, choose an alternative calcium supplement. Be sure to discard the calcium/vinegar solution after the test.
  • If you are taking acid blockers for indigestion, reflux or other gastrointestinal conditions, your body may use calcium citrate better than other calcium compounds. Acid blockers reduce the acid in your gastrointestinal tract that is usually required for calcium absorption. However, unlike other calcium compounds, calcium citrate does not require an acid environment for calcium absorption.
  • Read the supplement label to find out the calcium content in milligrams (mg) per serving. The label may refer to the calcium as elemental calcium. This distinguishes the weight (mg) of calcium alone from the weight (mg) of the calcium compound (such as calcium carbonate, calcium citrate, calcium phosphate, or others). It is also important for you to check the serving size to find out how many tablets or capsules provide a specific amount of calcium.
  • Although vitamin D is readily available in combination with calcium supplements, supplemental vitamin D should only be taken when your daily requirement for vitamin D is not met. If you are over 70 or a homebound individual, you should discuss your risk of vitamin D deficiency with your doctor. For more information, see "Vitamin D and Bone Health".
  • Magnesium supplements are not required for most healthy individuals. Magnesium is plentiful in a healthy, well-balanced diet. However, certain individuals may be at risk for magnesium deficiency including those with gastrointestinal diseases that cause poor absorption or increased losses of magnesium, frail elderly individuals eating poor diets, alcoholics, individuals receiving chemotherapy and those taking high dose diuretics (water pills) that deplete magnesium. Magnesium deficiency is easily diagnosed by a simple blood test. Your medical professional will prescribe a magnesium supplement if it is necessary or if you have a disease or condition that causes magnesium deficiency.
  • A well-balanced diet following the food-pyramid approach to good nutrition including adequate calcium and vitamin D is what you need to achieve and maintain healthy bones. For most healthy individuals, additional vitamins or minerals (such as magnesium, boron, vitamin K, selenium or others) in the form of supplements are not required for bone health. In fact, many of these nutrients will be present in a diet with five or more servings of fruits and vegetables a day.


Calcium carbonate provides forty percent elemental calcium, meaning that a 1,250mg of calcium carbonate yields 500mg of elemental calcium.  Advantages of calcium carbonate are that it has the highest percentage of elemental calcium and it has a track record of effectiveness.  It is best taken with meals to be properly absorbed.  A disadvantage can be that for some individuals calcium carbonate may cause constipation or gas  Here are some formulations of calcium carbonate:

Name Type Strength per tab    (in mgs) Elemental Calcium (in mgs)
Alka-Mints calcium carbonate 850 mg 340 mg
Caltrate calcium carbonate 1500 mg 600 mg
OsCal calcium carbonate 625 or 1250 mg 250 or 500 mg
Rolaids calcium carbonate 550 mg 220 mg
Titralac Tablets calcium carbonate 420 mg 168 mg
Titralac Liquid calcium carbonate 1000 mg 400 mg
Tums and Tums E-X calcium carbonate 500 or 750 mg 200 or 300 mg
Tums Ultra and Tums 500 calcium carbonate 1000 or 1250 mg 400 or 500 mg


 Calcium citrate provides twenty one percent elemental calcium.  Studies using calcium citrate show that it is an easily absorbed calcium supplement.  It can be taken at any time without regard to food.  The disadvantages are that it has a relatively lower percent of elemental calcium than calcium carbonate, therefore, you have to take more tablets of it to equal the same amount of elemental calcium in calcium carbonate.

Name Type Strength per tab Elemental Calcium
Citracal Liquidtabs calcium citrate 2376 mg 500 mg
Citracal calcium citrate 950 mg 200 mg
Citracal Caplets + D calcium citrate 1500 mg 315 + 200 I.U. vitamin D3


 Tribasic calcium phosphate provides thirty nine percent elemental calcium. It also is an easily dissolved and well-absorbed supplement that should not cause gas or constipation.  It can be taken anytime.  Calcium phosphate is the formulation used in specially calcium fortified orange juice, soy milk, and rice milk available.

Name Type Strength per tab Elemental Calcium
Posture calcium phosphate 1500 mg 600 mg
Posture-D calcium phosphate 1500 mg 600 mg + 125 I.U. vitamin D


The term elemental calcium refers to the amount of calcium in a product. Many calcium supplements list the amount of calcium, or elemental calcium, on the label. But some brands list only the total weight of each tablet, not the actual amount of calcium. If you know the type of calcium compound (check the label), you can calculate the amount of calcium in the product using the following formulas.
type of calcium supplement

percentage of calcium

multiply the weight of the capsule by Example
Calcium Carbonate

(40 percent)

0.4 500 mg calcium carbonate x 0.4 =

 200 mg calcium

Calcium Citrate

(21 percent)

0.21 950 mg calcium citrate  x 0.21=  

200 mg calcium

Calcium Lactate

(13 percent)

0.13 1,550mg calcium lactate x 0.013=

200mg calcium

Calcium Gluconate

(9 percent)

0.09 2,200mg calcium gluconate x 0.09 =

 200mg calcium



How do I take my calcium supplement?

  • It is important to read supplement labels and follow the directions for use.
  • When your calcium supplement is well absorbed, your body can easily use it. For best absorption, most calcium supplements should be taken with food. Calcium citrate is an exception; it can be taken with or without food.
  • It is best to spread out the calcium you consume from diet and/or supplements throughout the day. In fact, for best absorption, it is recommended to consume 500mg of calcium or less at one time.

Are there any special considerations?

  • If your medical professional recommends an iron supplement and you are also taking a calcium supplement, it is important that your body absorbs both nutrients. For the best absorption of both iron and calcium, it is recommended to take your calcium supplement 2 hours before or after your iron supplement. You should not take them at the same time.
  • Calcium interferes with the body's ability to use certain antibiotics, tetracycline for example. If your doctor prescribes tetracycline, it is important for you to take it properly. Therefore, you should not take calcium supplements (or eat calcium-rich foods) at the same time as tetracycline. Your antibiotic will work best if you take your calcium supplement (or eat calcium-rich foods) 2 hours before or after taking tetracycline. It is always important to speak to your pharmacist about the proper way to take your medication.
  • Some people who take calcium supplements complain about constipation. The best way to prevent constipation, is to eat more fiber in your diet from fruits, vegetables, and whole grain products as well as to drink 6 to 8 glasses of water each day. If these simple steps are not helpful enough, take a closer look at your diet to try to get more calcium from foods and less from supplements. Read the label for the amount of calcium in each dose. A lower dose calcium supplement may be better tolerated than a high dose supplement. In general, calcium carbonate has the highest amount of calcium per dose. Calcium citrate has less calcium per dose and calcium gluconate is one of the lowest dose options.



Most brand name calcium products are absorbed easily in the body. If the product information does not state that it is absorbable, how well a tablet dissolves can be determined by placing it in a small amount of warm water for 30 minutes, stirring it occasionally. If it hasnít dissolved within this time it probably will not dissolve in the stomach. Chewable and liquid calcium supplements dissolve well because they are broken down before they enter the stomach.

It's best to take most calcium supplements with meals. The acid secreted by the stomach during digestion enhances absorption of most calcium supplements, especially calcium carbonate. And the presence of other nutrients may also promote absorption. Calcium citrate is an exception: it doesn't need stomach acid to be absorbed, so you can take it any time (this makes it good for people who have disorders in which the stomach produces less acid).

Calcium, whether from the diet 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 any time.

Calcium Interactions

It is important to talk with a physician or pharmacist about possible interactions between prescription or over-the-counter medications and calcium supplements. For example, calcium supplements also may reduce the absorption of the antibiotic tetracycline. Calcium also interferes with iron absorption, so a calcium supplement should not be taken at the same time as an iron supplement. The exception to this is when the iron supplement is taken with vitamin C or calcium citrate. Any medication to be taken on an empty stomach should not be taken with calcium supplements.

Combination Products

Calcium supplements are available in a dazzling array of combinations with vitamins and other minerals. While vitamin D is necessary for the absorption of calcium, it is not necessary that it be in the calcium supplement (see winter 1998 issue of Osteoporosis Report for information on vitamin D). 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.

Most published studies show that low calcium intake is associated with low bone mass, rapid bone loss and high fracture rates. Adequate calcium intake will help ensure that calcium deficiency is not contributing to a weakening of the skeleton; however, this is only one of the steps necessary for bone health. A high calcium intake will not protect a person against bone loss caused by estrogen deficiency, physical inactivity, smoking, alcohol abuse or various medical disorders or treatments.

Beware of the following products which are scams:   

coral calcium

MCHC aka Bone Builder

wild yam cream





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Young People Get Osteoporosis Too Organization
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Revised: 03/11/08.