Whether you are 6 or 60, you never outgrow the need for Calcium. Most adults are recommended Calcium Supplements based on their medical history and deficiency status. So here is a brief on the different types of Calcium Supplements & how is their absorption.
Calcium Carbonate: Most calcium supplements currently on the market are in the form of calcium carbonate. While calcium carbonate contains the highest percentage of elemental calcium (40%), it is not absorbed as well as some other forms. Calcium carbonate requires extra stomach acid so that it can be dissolved and absorbed. It is best to take calcium carbonate supplements with food or a meal because the extra food will cause the stomach to increase its production of stomach acid.
Calcium Citrate: Calcium citrate is the second most common calcium supplement available on the market. It contains a lower percentage of elemental calcium (21%), but it is more easily absorbed by the body. It is not necessary to take calcium citrate with food because the citrate provides enough acid to help the body absorb the calcium.
Calcium Phosphate: Calcium phosphate contains the second highest percentage of elemental calcium (38%). Calcium phosphate can be taken with or without food, but may not be absorbed as well as calcium carbonate or calcium citrate.
Calcium Lactate & Calcium Gluconate: These forms of calcium supplements are not widely available and contain small amounts of elemental calcium.
Coral Calcium: Makers of coral calcium made claims that this calcium supplement not only improves bone density, but it can also help to prevent diseases like cancer, heart disease, high blood pressure, multiple sclerosis and lupus. While it can, in fact, help to improve bone mineral density, it is not effective in helping to prevent any other disease.
Dolomite, Bone Meal & Oyster Shell: It is best to avoid these forms of calcium supplements because they may contain high levels of lead and other toxic metals.