While fewer pills of the calcium carbonate form are needed, this form doesn't absorb as well as some other forms of calcium. CCM is increasingly the form of calcium recommended by nutritionally oriented doctors. Only preliminary research exists regarding the amino acid chelates of calcium, and conclusions cannot be drawn at this time. Severe deficiency of both calcium and vitamin D is called rickets in children and osteomalacia in adults. Vegans often eat less calcium and vitamin D than others.
Most people eat well below the recommended amount of calcium.
This lack of dietary calcium is thought to contribute to the risk of osteoporosis, particularly in white and Asian women. Constipation, bloating, and gas are sometimes reported with the use of calcium supplements. This toxicity is rarely reported today because most medical doctors no longer tell people with ulcers to take this combination. People with hyperparathyroidism, or chronic kidney disease should not supplement with calcium without consulting a nutritionally oriented physician. People who have had kidney stones should read the section on kidney stones before considering supplementation.