Hi Tammy.. I am Linda, the new Altmed host. My brother suffers from a calcium deficiency and so did my mother. In fact, my brother who is also downs syndrome was having seizures due to his inablility to "bind" calcium into his system. He is on a special medication that does just that. He also takes calcium with magnesium. The only problem I can see that may be related to coral calcium is the same issue related to oyster-shell , dolomite, and bone meal.. the possibility of high lead content. Calcium which is bound to citrate is probably the best. Magnesium is equally as important as calcium so you should make sure to take both together. Soy in its natural form is also high in calcium, although many of the soy drinks available are so diluted or have so many additives they are not considered to be a good choice. Of course, the best course of action is to take a walk in the sunshine everyday for the vitamin D content, and to consume as many natural calcium rich foods as possible.