Calcium absorption by body is regulated by many factors.
Calcium is stored in the body in the bones making up 99% of the mineral. The rest of the 1% is found in the body fluids.
This mineral is available through food and is absorbed and used for the growth and repair of bones and some of it is excreted in urine.
Parathyroid hormone regulates the availability in serum and if required sourcing it from the bone mass.
For the mineral to get sufficiently absorbed from intestine, vitamin D plays an important role by increasing the binding proteins.
The best source is milk and milk products and calcium through this source is absorbed excellently.
Sea weeds like kelp, almonds, beans, sesame, figs and oranges are some of the natural sources essential minerals.
Supplements are available in many forms and mostly with added vitamin D.
Health specialists recommend 1250 mg of elemental calcium per day split in to two or three doses for adults.
Its absorption decreases with one time dose of 500mg and above and hence the advice of splitting the dose.
Supplements in the form of calcium carbonate (CaCO3) are the most common and are the least expensive.
Antacids also contain CaCO3 and they can be used effectively as supplements if they contain predominant amount of available mineral.
Calcium citrate and phosphate are other useful supplements available but are expensive.
Supplements like calcium lactate and gluconate apart from being expensive contain less of elemental calcium.