Calcium and magnesium in drinking water and human health

Calcium and magnesium are the primary components in water that people associate with hard water. Many people would not notice were it not for the telltale white buildup on faucets and fixtures that people recognize as hard water residue. What you don’t like on your showerheads and faucets is essential for human health.

Water hardness seems to be inversely correlated with heart attacks (myocardial infarctions; Rubenowitz, Axelsson, & Rylander, 1996), specifically the magnesium (Rubenowitz, Axelsson, & Rylander, 1998), rather than the calcium, in the water. Calcium and magnesium, which traditional water softeners replace with sodium and potassium, is necessary for proper functioning of cells, including neuromuscular functions; magnesium activates the enzyme essential to this functioning. The heart is a muscle in humans and other animals and its proper functioning depends on magnesium, which water softeners intentionally remove.

Scientific studies find significant correlation between drinking water and cancer. Water hardness also seems to be inversely correlated with deaths from colon cancer (Yang & Hung, 1998). In this case, the primary benefactor seems to be calcium rather than magnesium in the drinking water. Yang, Chiu, Cheng, Tsai, Hung, and Lin (1999) noted that water hardness is similarly inversely correlated with esophageal cancer mortality.

Scientific research consistently finds benefits to calcium and magnesium in the human diet. For many people, the calcium and magnesium found in their municipally-supplied water in their homes is a primary dietary source. Traditional, ion-exchange water softeners replaces the calcium and magnesium that your body needs, but your fixtures do not, with sodium and potassium, which your cells also need, but which have documented detrimental side effects. A template-assisted crystallization system from Water4 Systems does not remove the calcium and magnesium, but simply converts it into a form that will not, or at least only nominally, build up on a home’s fixtures and surfaces.


Nerbrand, C., Agréus, L., Lenner, R. A., Nyberg, P., & Svärdsudd, K. (2003). The influence of calcium and magnesium in drinking water and diet on cardiovascular risk factors in individuals living in hard and soft water areas with differences in cardiovascular mortality. BMC Public Health, 321-9.

Rubenowitz, E., Axelsson, G., & Rylander, R. (1996). Magnesium in drinking water and death from acute myocardial infarction. American journal of epidemiology, 143(5), 456-462.

Rubenowitz, E., Axelsson, G., & Rylander, R. (1998). Magnesium in drinking water and body magnesium status measured using an oral loading test. Scandinavian Journal Of Clinical & Laboratory Investigation, 58(5), 423-428. doi:10.1080/00365519850186409

Yang, C. Y., Chiu, H. F., Cheng, M. F., Tsai, S. S., Hung, C. F., & Lin, M. C. (1999). Esophageal cancer mortality and total hardness levels in Taiwan’s drinking water. Environmental research, 81(4), 302-308. doi:10.1006/enrs.1999.3991

Yang, C., & Hung, C. (1998). Colon cancer mortality and total hardness levels in Taiwan’s drinking water. Archives of Environmental Contamination and Toxicology, 35(1), 148-151. doi: 10.1007/s002449900362