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The link between hard, soft water and cardiovascular disease.

There is currently a medical controversy over what effect, if any, drinking hard or soft water may have on heart disease. In some areas with naturally soft water, residents seem to suffer more from heart disease. In other areas, there appears to be no difference between drinking hard and soft water. A number of researchers feet that some other constituent of water -- not hardness or softness may be responsible for the variations in heart disease figures in different areas of the country.

Some researchers believe that very small amounts of a "protective" substance may be present in some water supplies and lacking in others. This unknown substance could have a beneficial effect on the heart in much the same way that minute amounts of fluoride protect the teeth. At the present time, no one knows exactly what this substance may be. Other scientists feel that the problem might be caused by other elements, such as cadmium, in the drinking water. It is known that this metal can cause high blood pressure when taken in small quantities. Trace amounts of cadmium can be dissolved from galvanized water pipes by the corrosive action of naturally soft water.

Over the years many studies have been published on the relationship between drinking water and cardiovascular mortality. Two beneficial factors continually stand out -hardness and total dissolved solids. Both have been associated with lower mortality from heart disease. Hardness refers to the amount of calcium and magnesium, or calcium carbonate in the water. The more calcium carbonate, the harder the water; the less, the softer the water. The first major study on drinking water and heart disease was in 1960 by Schroeder. In his paper, "Relation Between Mortality from Cardiovascular Disease and Treated water Supplies,' the water in 163 largest cities in the United States was analyzed for 21 constituents and correlated to heart disease.

He concluded "some factor either present in hard water, or missing or entering in soft water is associated with higher death rates from degenerative cardiovascular disease." In 1979 after reviewing fifty studies, Corn stock concluded, "there can be little doubt that the associations of water hardness with cardiovascular mortality are not spurious. Too many studies have reported statistically significant correlations to make chance or sampling errors a likely explanation." He suggests that the reason for this association is due to a "deficiency of an essential element or an excess of a toxic one." Certainly a combination of both is also possible.

Today after thirty years of research we are left with Schroeder's initial conclusion-drinking hard water results in less cardiovascular disease than drinking soft water. Yet over the years there have been several published reports analyzing specific elements in drinking water and their possible relationship to heart disease. One researcher studies zinc, another copper; another selenium, and so on. And as you read this material, you find an inconsistent and confusing picture. But, if you look at the broader picture, if you look at the studies on hardness, you will find very consistent results: namely, the harder the water the less heart disease deaths.

Before highlighting some of the major studies let's discuss TDS, total dissolved solids. TDS is a measurement of all the minerals in drinking water TDS not only includes calcium and magnesium (the hardness factors), but also zinc, copper chromium, selenium and so on. Sauer analyzed 23 drinking water characteristics in 92 cities ("Relationship of Water to the Risk of Dying") and found people who drank water higher in TDS had lower death rates from heart disease, cancer and chronic diseases than people who drank water with low amounts of TDS. Frequently, where the water is hard the water is also high in TDS.

Although most studies on heart disease have not looked at TDS but at hardness, this factor has been ever present and may be playing a very significant role. The more we try to isolate and study the effects of individual minerals the more we can lose sight of the unifying, comprehensive, beneficial factors present in water like hardness, TDS, and pH. Perhaps one of the main reasons there are inconsistencies in the water story is simply because we are obsessed to locate a specific isolated element that is responsible for the beneficial effects of healthy drinking water. Lets look at some of the major studies. In Great Britain, the British Regional Heat Study analyzed 253 towns from 1969 to 1973. They found 10% to 15% more cardiovascular deaths in soft water areas than in hard water areas. They suggest that the ideal amount of hardness is approximately 170 mg/L (or ppm-parts per million).

In the United States, Greathouse and Osborne studied 4200 adults, ages 25 to 74 in 35 different geographic areas. Their findings? Again, less heart disease mortality in hard water areas than in soft water areas. A report by the Oak Ridge National Laboratory found that the calcium and magnesium in hard water reduces the risks of heart attacks and strokes. This study compared the health records of 1,400 Wisconsin mate farmers who drank well water from their own farms. The farmers who drank soft water suffered from heart disease, whereas, the farmers who drank hard water were, for the most part, free of the problem. Sometimes, the best experiments are those nature has been silently conducting for years. Some of the most revealing water studies are seen comparing two neighboring towns in which one town alters its hard water to create softer water.

What have been the effects of this action? A higher rate of heart disease mortality. We see this in the English towns of Scunthrope and Grimsby. Both towns drank the same water with 44.4 mg/L of hardness and had identical heart disease mortality rates. Scunthrope soften its water to 100 mg/L of hardness and within a few years a striking increase in cardiovascular deaths occurred. Whereas in Grimsby the rate was virtually the same as it had been. This pattern has also been reported in the Italian towns of Crevalcore and Montegiorgio and the Abruzzo region of Italy.

The National Academy of Sciences concluded, "An optimum conditioning of drinking water could reduce the amount of cardiovascular disease mortality by as much as 15% in the U.S. When looking at the research there is a definite relationship between water hardness and heart disease mortality. We should try to drink water that has approximately 170 mg/L of hardness; the level found Ideal In Great Britain. Second, there is a definite relationship with TDS and heart disease mortality. Higher levels of TDS results in less heart disease. Proper levels of hardness and TDS are two of the beneficial properties in drinking water constituting a healthy drinking water.