Calcium and Magnesium in Your Drinking Water
By C.F. ‘Chubb’ Michaud, MWS
As the world demand for good drinking water continues to grow, more and more of society is turning to the inexhaustible source of seawater desalination. Forced through membranes or distilled, seawater can be reduced in total dissolved solids (TDS) from around 35,000 to well below 100 TDS. Desal (desalinated) water is different. It is generally low in pH (5.0) and corrosive and must be adjusted for potability. Over six billion gallons are served around the world every day at present.
About 25 years ago, the question was raised on the long-term effects of consuming deminineralization, remineralization and/or altered mineral content drinking water. A meeting was held in Rome in 1983 to establish guidelines and procedures for modifying desal water. It was the data presented at that meeting that led to the hypothesis that waters low in calcium and magnesium are unhealthy and put the consumer at substantially higher risk of cardiovascular disease (CVD).
There are complex social, cultural, environmental and economic considerations now on the table for World Heath Organization (WHO). WHO maintains that they only put forth guidelines (not standards) and their purpose is only advisory of the protection of public health. There are two primary issues on drinking water: desalination and nutrient (mineral) content. WHO views calcium and magnesium as nutrients, while we of the water treatment trade view them as contaminants.
The International Life Sciences Institute (ILSI) sponsored a symposium in Baltimore, Md., April 24-26, 2006 to put all of the facts on the table regarding the role of calcium and magnesium in drinking water. This meeting was attended by about 150 researchers from 14 countries. There were over 50 papers and poster sessions presented and after three days, the entire issue was boiled down to a single question: Is tap water a significant source of calcium and magnesium?
Consumption of calcium and magnesium varies tremendously across the world. In Bangladesh, up to 40 percent of families are affected by rickets—caused by the lack of calcium in the diet. Studies have shown that this disease could be prevented by drinking as little as one liter of water containing 50 ppm of calcium a day. At least half of the world population is deficient in calcium and magnesium. It is estimated that here in the land of plenty, despite an obesity problem, up to 90 percent of men and women are below the recommended daily amount (RDA) for magnesium (320 mg/day). Calcium and magnesium in water has the same bioavailability as from milk. Calcium and magnesium deficiencies are not rare in the U.S. but hard to detect because serum levels of calcium and magnesium are very low numbers and usually appear normal even if the body is deficient. Calcium and magnesium absorption increase with increased intake but overall, decrease with age. Absorption increases by about five percent with food and increases with exercise as well.
There is one thing for sure that will come from a meeting of over one hundred researchers—disagreement. WHO now speaks in ranges and there are those who work the edges of the ranges, always using the data that supports their cause. However, of the more than 80 studies comparing the consumption of soft water with CVD done between 1957 and 2003, almost every study showed the inverse effect of increased CVD with decreased hardness. The correlation is far better with magnesium than with calcium or total hardness. Reports of a 10 to 26 percent reduction of CVD have been shown with only a six to 10 mg/L magnesium content in the water. In some parts of the world, calcium and magnesium are so deficient in the diet that WHO is considering adoption of guidelines for minimum levels for calcium and magnesium of 30 and 10 mg/L respectively. They feel that this level is significant even for the American diet. The role of calcium and magnesium in human health is so significant that you can almost plot body size and life expectancy with the total calcium and magnesium in the diet for various populations around the world.
The ‘Miracle of Magnesium’ studies suggest magnesium intake relates to lower risk of CVD, cancer, reduces cholesterol, discourages arterial plaque and even helps prevent metabolic syndrome and reduces stress. Low magnesium reduces bacteria in the gut (a bad thing) and sets up a pro-inflammatory state and leaky gut (another bad thing).
However, before you replace your salt shaker with magnesium chloride and start putting calcite on your corn flakes, consider that with ratios of calcium to magnesium of greater than six to one, there was a higher risk of CVD reported. And, the soft water used in these studies was aggressive, corrosive, low pH, low TDS, naturally soft water, not softened water as we know it. Such waters were further shown to leach copper and lead from pipes, which, in turn, were shown to elevate the risk of CVD. In other words, hard waters were non-corrosive and did not leach metals. WQA was quick to point out that softened waters are no more corrosive than hard waters. So was it the lack of magnesium or the excess of copper and lead that was doing the dirty work? Also, sudden death by heart attack was not considered a CVD by some studies because death is not a disease.
In controlled studies it was shown that when healthy people reduce their intakes of magnesium, they show it within weeks with heart arrhythmia. When healthy people increase their intakes of magnesium, not much happens.
Even though flawed, the studies seem to show an inverse relationship between hardness and CVD. When asked the question: ‘Is there a correlation of increased risk of cardiovascular disease associated with drinking soft water?’, my answer is: For hardness, probably not, for calcium, probably not and for magnesium, probably yes. Drinking mineralized water certainly does no harm and might actually help if the population is deficient. It would, however, be considered a minor source. The best change would be to increase the dietary intake.
If WHO had their way, the headlines in the morning paper would read “CAUTION: The long term consumption of softened water may be hazardous to your health.” Here is a research and advisory group that can’t even agree on the relationship between smoking and lung cancer that is now poised to advise the world that soft water is bad for you.
Between 1957 and 2003, more than 80 research studies were conducted comparing the incidence of CVD and the consumption of soft water. Almost every one of those studies showed an inverse correlation linking the lack of calcium and magnesium in drinking water and increased CVD (with best correlation shown between magnesium and CVD).
Of the total number of studies performed worldwide, only those written in English were selected for review. One of the problems with research is that things are often lost in translation. In fact, one of the researchers criticized the symposium group for not selecting more Eastern European and Russian papers—some of which called demineralized water poison.
The non-water treating world defines soft water as naturally occurring waters nearly devoid of all things mineral and generally characterized by a TDS less than 50 ppm, low pH and corrosive. Such waters were also found to be higher in leached minerals such as copper, zinc, cadmium and lead—all of which have been shown to have an adverse affect on the incidence of CVD. So, is it the lack of calcium and magnesium or the presence of cadmium and lead in the water that is causing the effect. In addition, some studies that compared softened water to hard water reported no observed difference but those softened waters were lime-softened. Lime softening removes calcium and reduces bicarbonate alkalinity (believed to be the root cause of corrosion) but leaves the magnesium. Controlled studies where total dietary calcium and magnesium were examined did show the relationship with magnesium and CVD.
WQA noted that hard waters that undergo softening are generally high in TDS, higher in pH, non-aggressive, non-corrosive and do not pose the same threat as naturally soft or demineralized waters produced by RO or distillation of seawater.
The bottom line
In healthy populations, if the diet is suddenly reduced in magnesium, the signs of CVD soon appear. If dietary magnesium is increased, not much happens. It seems perplexing that in the U.S. where we have a recognized obesity problem, it is estimated than over 90 percent of the population has a diet deficient in magnesium.
In parts of the world where dietary calcium and magnesium are seriously deficient, WHO considers that every little bit is needed and significant and they may take a position of advising in favor of a minimum level of calcium and magnesium in drinking water.
Is all of this likely to have an impact on the future of the water softener business at home? Probably not. But the stigma may persist.
About the author
C.F. ‘Chubb’ Michaud is the CEO and technical director of Systematix Company, of Buena Park, Calif., which he founded in 1982. An active member of the Water Quality Association, Michaud has been a member of the Board and of the Board of Governors and chaired the Commercial/Industrial Section. He is a Certified Water Specialist Level VI. He has served on the Board of Directors of the Pacific WQA since 2001 and chairs its technical committee. He was a founding member of (and continues to serve on) the Technical Review Committee for WC&P and has authored or presented over 100 technical publications and papers. He can be reached at Systematix Inc., 6902 Aragon Circle, Buena Park CA 90620, telephone (714) 522-5453 or via email at cmichaud@systematixUSA.com