Calcium Supplements

Posted by Blog Sunday, March 6, 2011

Calcium in supplements is found in many forms. The least absorbable forms are calcium carbonate, dolomite, and oyster shells. These forms are sometimes contaminated with lead, arsenic, cadmium, or mercury. Absorption of these forms of calcium is usually well under 10 percent. These elemental forms of calcium can easily bind to dietary oxalates and phytates, which results in their excretion.

Calcium in food is normally chelated to other nutrients. Minerals are chelated when they are bound to organic molecules. Calcium in supplements is often chelated to citrates, lactates, and gluconates. These forms are easily broken apart in the stomach, which limits their absorption. If taken with food, the free calcium can combine with amino acids in the food, which aids their absorption. Some supplementary calcium comes already chelated with amino acids. Amino acid chelates are not easily broken up in the stomach and are readily taken up by intestinal cells.

Certain chelating agents can act as mineral transporters. Calcium aspartate, calcium ascorbate, and calcium orotate are very well absorbed and easily transported to the cells where they are needed. Most of the calcium needed should come from the diet, rather than supplements. Calcium is a bulky nutrient and a whole day’s supply will not fit conveniently into a tablet. For best absorption, iron or zinc supplements should not be taken at the same time as calcium supplements. Tetracycline should also be taken at a different time than calcium supplements.

Summary for Calcium

Main functions: bones and teeth, muscle contraction, and blood clotting.

Adequate Intake: for adults and adolescents, 1000 to 1300 mg per day.

Toxicity is rare.

Tolerable upper intake level is set at 2500 mg for ages one and above.

Deficiency can cause stunted growth in children and osteoporosis in adults.

Sources: dairy products, almonds, tofu, sesame seeds, vegetables, and beans.

Forms in the body: free calcium ions in blood and hydroxyapatite in bones.

Alternatives to supplemental calcium include more calcium in the diet, more sunshine, keeping protein intake to the RDAs, keeping sodium levels below the upper intake levels, and regular weight-bearing exercise.

More about Calcium:


Bone Remodeling

Calcium and Muscle Contraction

How Calcium Is Regulated in the Blood

Deficiency of Calcium

Calcium and Osteoporosis

Food Sources of Calcium

Calcium Supplements

Calcium Toxicity


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