Calcium and magnesium are both essential elements. Calcium is a substantial component of teeth and bones. In addition, it plays a role in neuromuscular excitability, the proper function of the conducting myocardial system, muscle and heart contractility, intracellular information transmission and the coagulability of blood. Magnesium plays an important role as a cofactor and activator of more than 300 enzymatic reactions including glycolysis, ATP metabolism, transport of elements such as sodium, calcium and potassium through membranes, synthesis of proteins and nucleic acids, neuromuscular excitability and muscle contraction.
Although drinking water is not the major source of our magnesium and calcium intake, the health significance of supplemental intake of these elements from drinking water may outweigh its nutritional contribution expressed as the proportion of the total daily intake of these elements. Even in industrialized countries, diets not deficient in terms of the quantity of calcium and magnesium, may not be able to fully compensate for the absence of calcium and, in particular, magnesium, in drinking water.
Drinking water, with some rare exceptions, is not the major source of essential elements for humans, however, it’s contribution may be important for several reasons. The modern diet of many people may not be an adequate source of minerals and microelements. In the case of borderline deficiency of a given element, even the relatively low intake of the element with drinking water may play a relevant protective role. This is because the elements are usually present in water as free ions and therefore, are more readily absorbed from water compared to food where they are mostly bound to other substances.
Since the early 1960’s, epidemiological studies in many countries all over the world have reported that water low in magnesium and calcium and is associated with increased morbidity and mortality from cardiovascular disease.
Recent studies also suggest that the intake of water low in calcium (reverse osmosis water), may be associated with higher risk of fracture in children (Verd Vallespir et al. 1992), certain neurodegenerative diseases (Jacqmin et al. 1994), pre-term birth and low weight at birth (Yang et al. 2002) and some types of cancer (Yang et al. 1997; Yang et al. 1998). In addition to an increased risk of sudden death (Eisenberg 1992; Bernardi et al. 1995; Garzon and Eisenberg 1998), the intake of water low in magnesium seems to be associated with a higher risk of motor neuronal disease (Iwami et al. 1994), pregnancy disorders (so-called preeclampsia) (Melles & Kiss 1992), and some types of cancer (Yang et al. 1999a; Yang et al. 1999b; Yang et al. 1999c; Yang et al. 2000).
Recent epidemiological studies suggest that reverse osmosis water may be a risk factor for:
- coronary heart disease
- duodenal and gastric and duodenal ulcers
- chronic gastritis
- pregnancy complications
- complications in newborns and infants, including jaundice, anemia, fractures and growth disorders.
When used for cooking, reverse osmosis water was found to cause substantial losses of all essential elements from food (meats, vegetables, cereals). Such losses may reach up to 60% for calcium and magnesium or even more for some other micro-elements (e.g., copper 66%, cobalt 86%, manganese 70%). In contrast, when mineralized water is used for cooking, the loss of these elements is much lower, and in some cases, an even higher calcium content was reported in food as a result of cooking.
The current diet of many persons usually does not provide all necessary elements in sufficient quantities, and therefore, any factor that results in the loss of nutrients and essential elements during the processing and preparation of food could be detrimental for them.
In a multi-city study, women living in cities with low-mineral water more frequently showed cardiovascular changes (as measured by ECG), somatoform autonomic dysfunctions, headache, higher blood pressure, dizziness, and osteoporosis (as measured by X-ray absorptiometry) compared to those of cities with higher mineral content water.