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


Drinking Water and Cancer

Contaminants enter the drinking water supply in one of three ways.  Contaminants may enter the source water.  Contaminants may be added to the water during the treatment process.  The consumer may also add contaminants to the drinking water supply.  Morris (1995) noted that arsenic, asbestos, radon, agricultural chemicals, and hazardous waste are primary concerns, although chlorine and chlorine byproducts receive increased attention as carcinogens.  Arsenic is associated with liver, lung, bladder, and kidney cancers.  The byproducts of chlorination of municipal water supplies may contribute to 5000 bladder cancer cases and 8000 rectal cancer cases annually in the United States alone.  Morris reported no such apparent risks associated with fluoridation.  Morris also noted that the risk of asbestos in drinking water does not appear significant and that radon in drinking water may contribute to 100 cancer cases annually in the United States.  The primary likely source of asbestos in the drinking water is concrete-asbestos pipes in the water distribution system.

DeRouen and Diem (1975) reviewed the concerns raised by the Environmental Defense Fund and the Environmental Protection Agency over the presence of 66 chemicals in the water supply of New Orleans, LA.  The authors noted the increased risk of urinary tract and gastrointestinal cancers related to the presence of the chemicals and encouraged a new primary water supply source or improved purification methods.  Kuzma, Kuzma, and Buncher (1977) wrote of similar concerns over stomach and bladder cancers due to exposure to volatile organic compounds in public water supplies in Ohio.

Morris (1995) noted the increasing concern about biologically active micropollutants or endocrine disrupters.  These compounds may disturb normal intercellular communications and, as a consequence, disrupt certain biological functions.

Morris (1995) reported that the evidence relating volatile organic compounds and hazardous waste in general in drinking water to leukemia seems weak.  Trichlorethylene leaching from plastic liners within concrete pipes seems associated with increased leukemia risk.  Morris observed that chlorination, despite the risks, continues to provide benefits in the water distribution process.  The key for consumers may be to remove the chlorine and chlorine byproducts at the end of the water distribution system, after it enters the home or other point of use.

Koivusalo, Vartiainen, Pukkala, and Jaakkola (1995), studying the presence of certain chlorine byproducts in drinking water in Finland in relation to the certain cancers, concluded that the presence of acidic, mutagenic compounds in drinking water increases risk of lymphomas and pancreatic cancer.  Koivusalo et al. looked at both volatile and non-volatile organic compounds with and without consideration of pH.  Koivusalo et al. expressed specific concern about the presence of 3-chloro-4(dichloromethyl)-5-hydroxy-2(5H)-furanone, also known as mutagen X, because its production as chlorine byproduct does not seem to be pH dependent. Koivusalo et al. previously  noted the increased risk of exposure to such compounds for urinary tract and gastrointestinal cancers (Koivusalo, Jaakkola, Varliainen, Hakulinen, Karialainen, Pukkala, &  Tuomisto, 1994).  Mancaş, Vartiainen, Rantakokko, Navrotescu, Diaconu, Mancaş, and Diaconu (2002) did a comparable study in Romania with similar conclusions.

Doyle, Zheng, Cerhan, Hong, Sellers, Kushi, and Folsom (1997) noted, based on a study of postmenopausal women in Iowa, that chlorination of drinking water and exposure to chlorination byproducts appears to increase the likelihood of colon and other cancers in women.

Margel and Fleshner (2011) noted a possible relationship between exposure to estrogen in drinking water supplies and prostate cancer.  The study analyzed data from 87 countries and concluded that oral contraceptive use seems to have a high likelihood of being the source for estrogen in drinking water.


DeRouen, T., & Diem, J. (1975). The New Orleans drinking water controversy: A statistical perspective.  American Journal of Public Health, 65(10), 1060-1062.

Doyle, T., Zheng, W.,  Cerhan, J., Hong, C., Sellers, T., Kushi, L., & Folsom, A. (1997). The association of drinking water source and chlorination by-products with cancer incidence among postmenopausal women in Iowa: A prospective cohort study. American Journal of Public Health, 87(7), 1168-1176.

Koivusalo, M., Jaakkola, J., Varliainen, T., Hakulinen, T., Karialainen, S., Pukkala, E., &  Tuomisto, J. (1994). Drinking water mutagenicity and gastrointestinal and urinary tract cancers: An ecological study in Finland. American Journal of Public Health, 84(8), 1223-1228.

Koivusalo, M., Vartiainen, T., Pukkala, E., & Jaakkola, J. (1995). Drinking water mutagenicity and leukemia, lymphomas, and cancers of the liver, pancreas, and soft tissue. Archives of Environmental Health, 50(4), 269-276

Kuzma, R., Kuzma, C., & Buncher, R. (1977). Ohio drinking water source and cancer rates. American Journal of Public Health, 67(8), 725-729.

Mancaş, G., Vartiainen, T., Rantakokko, P., Navrotescu, T., Diaconu, R., Mancaş, D., & Diaconu, D. (2002). Chemical contaminants in drinking water: Mutagenic and toxic effects. The Journal of Preventive Medicine, 10(3), 63-74.

Margel, D., & Fleshner, N. (2011). Oral contraceptive use is associated with prostate cancer: an ecological study. BMJ Open, 1(2), 1-10. doi:10.1136/bmjopen-2011-000311

Morris, R. (1995). Drinking water and cancer. Environmental Health Perspectives Supplements, 10780475, 8(103), 225-232.