Mineral water is categorized by its purity at source, its content in minerals, trace elements and other constituents, its conservation and its healing properties. Based on total salt content, mineral waters can be classified as: waters with a very low mineral content, waters low in mineral content, waters with a medium mineral content, and strongly mineralized waters. Based on ion composition, mineral waters can be classified as: bicarbonate waters, sulfate waters, and sodium chloride or saltwater. Based on biological activity, mineral waters are usually classified as: diuretic waters, cathartic waters, waters with anti-inflammatory properties (Petraccia, 2006). But mineral water seems to have much more health benefits for various organ and systems, depending on its specific composition.
Skin hydration. Measurements of skin thickness and density before and after consumption of mineral versus tap water showed that mineral water might have a superior skin hydrating effect (Williams, 2007).
Calcium metabolism. High-calcium mineral waters can provide significant amounts of calcium to the body (Heaney, 2006). A few years ago, a combined analysis of the most relevant existing studies showed that calcium absorption from mineral waters was significantly higher than that from dairy products (Bohmer, 2000). Such waters are thus recommended to achieve optimal calcium requirements, especially in aged people with lactose intolerance (Wynckel, 1997).
Kidney stones. The vast majority of kidney stones are made of calcium oxalate salts that precipitate in the urine. On the other hand, urinary citrate, magnesium, and alkaline (high) pH are some of the main factors that impede stone formation. In people who drink water with high and medium calcium contents, calcium urinary elimination may slightly increase; however, oxalate elimination significantly decreases, as well as the oxalate-to-calcium ratio. Therefore, high-calcium mineral waters do not favor but, quite the opposite, they prevent kidney stones (Caudarella, 1998). Moreover, consumption of mineral waters rich in magnesium and bicarbonate can increase urinary pH, magnesium, and citrate (Siener, 2004) and decrease calcium oxalate concentration (Kessler & Hesse, 2000).
Tooth cavities. An Italian survey among schoolchildren found that consumption of commercial bottled mineral water prevents dental caries of the primary dentition (Perinetti, 2005).
Osteoporosis. Consumption of high-calcium mineral water was shown to decrease the markers of bone decay in postmenopausal women (Meunier, 2005). Total calcium intake is directly linked with bone density (Aptel, 1999). In addition, bicarbonate-rich waters improve biological availability of calcium, calcium-phosphate hormonal regulating balance, bone breakdown, and bone density (Costi, 1999). Both bicarbonate and potassium are able to reduce urinary calcium loss and bone destruction in short and medium term studies (Burckhardt, 2004). Therefore, calcium, bicarbonate, and potassium-containing waters may prevent osteoporosis, especially in women after menopause.
Carbohydrate, fat metabolism, and cardiovascular risk. Studies have proven sulfurous waters have antioxidative properties (Benedetti, 2007), whereas bicarbonate-rich waters can limit the increase of lipid blood levels after meals (Schoppen, 2005) and improve insulin sensitivity (Schoppen, 2006). Another research by Schoppen and co-workers (2004) provided more interesting results: drinking sodium-rich carbonated water was associated with a significant lowering in total cholesterol and LDL- ("bad") cholesterol levels by almost 7% and 15%, respectively, and an increase in HDL- ("good") cholesterol by 9%. Inflammation markers and fasting blood glucose concentration also decreased. All these effects indicate a reduction of total cardiovascular risk (Schoppen, 2004).
Hypertension and cardiovascular disease. A decrease in blood pressure was observed in persons with magnesium or calcium deficiency after drinking mineral water (Rylander & Arnaud, 2004). The blood pressure-lowering effects of magnesium (Jee, 2002), calcium (Bucher, 1996), and potassium (Whelton, 1997) have previously been established by others. Fifty years ago, Kobayashi in Japan was the first to describe a relation between mortality from coronary heart disease and drinking water characteristics. Since then, several studies have confirmed this relationship (Rylander, 1996; Marx & Neutra, 1997; Kousa, 2004), while others have denied it (Nerbrand, 2003; Al-Delaimy, 2004). However, a remarkable investigation found magnesium- and calcium-rich water drinking to decrease death from acute myocardial infarction (Rubenowitz, 2000).
Last but not least, it is important to mention that mineral water is also safer than tap water when it comes to microbial contamination risks. A systematic analysis of medical reports in several Western countries (Bohmer & Resch, 2000) found a total number of 423,000 cases of disease outbreaks (mainly diarrhea) due to contaminated tap water, some of these with lethal outcome; in contrast, there was no such documented case in relation to bottled mineral water.
In conclusion, mineral waters have shown beneficial effects on bones, kidneys, and heart. Since no adverse reactions have been reported, drinking mineral waters with specific compositions can be recommended for people who are prone to develop kidney stones, osteoporosis or cardiovascular disease.