Calcium Carbonate And Bone
by Michael Mooney (May, 2006)
Large manufacturers of nutrient raw materials who are vendors of more expensive forms of calcium, like calcium citrate, have produced a misinformation campaign over dozens of years that calcium carbonate is inferior and that it doesn't absorb well or build bone as well as their forms of calcium. These statements are exaggerated and generally based on flawed studies, and studies that have been created to support their product, as is shown in my paper that details questions about calcium. Click here to read it.
One interesting statement that has been spread around the natural foods marketplace that I hear frequently is that calcium carbonate is "not natural and can't be used to build bone."
Many studies show this to be incorrect. Referenced below are six studies that discuss what components are contained in bone, stating that carbonate is a natural component that is made in bone (as is citrate). (1,2,3,4,5,6) Click here to see the front page of two studies on the "nature of bone carbonate."
If your bones are dried to bone mineral ash, commonly-known biochemistry tells us that about 2 percent of it is calcium citrate, 10 percent of it is calcium carbonate and about 65 percent of it is calcium hydroxyapatite. (6) Carbonate is made in the body in the body's natural calcium manufacturing cycle that ends up producing hydroxyapatite, the major form of calcium in bone, so carbonate is critical to healthy bone formation.
I have also heard people say that since calcium carbonate is inorganic it can't be used for bone. This statement is also inaccurate.
The idea that because calcium carbonate is chemically classified as an "inorganic mineral so it can't be used to build bone" is based on a misunderstanding. It seems that people misunderstand what "organic" and "inorganic" mean in this context. Organic, in the world of chemistry does not mean that a substance is pesticide free and "all-natural." It means that the substance has a carbon molecule in it. Human bone is known to contain both organic AND inorganic minerals. (3,4)
Additionally, calcium carbonate has been conclusively shown to imcrease bone density in groups like older women, and even in newborn babies whose mothers take calcium carbonate during their pregnancy, so it does absorb and is used for healthy functions in the body. (See pages 8 and 9.)
1. Biltz RM; Pellegrino ED. The nature of bone carbonate. Clin Orthop. 1977 Nov-Dec;(129):279-92.
2. Buchanan DL; Nakao A. Studies on the nature of bone carbonate. Arch Biochem Biophys. 1958 Sep;77(1):168-80.
3. Green J. The physicochemical structure of bone: cellular and non-cellular elements. Miner Electrolyte Metab. 1994;20(1-2):7-15.
4. Posner AS. The chemistry of bone mineral. Bull Hosp Joint Dis. 1978 Oct;39(2):126-44.
5. Posner AS. Bone mineral on the molecular level. Problems in Calcium Metabolism. Federation Proceedings, Sept. 1983; 32(9):1933-37.
6. Orthopaedics: Principles and Applications, by Samuel L. Turek, MD. Lippincott, 1985. 2nd Edition