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Natural mineral bottled waters available on the Polish market as a source of minerals for the consumers. Part 1. Calcium and magnesium.

BACKGROUND
Natural mineral waters may be an essential source of calcium, magnesium and other minerals. In bottled waters, minerals occur in an ionized form which is very well digestible. However, the concentration of minerals in underground waters (which constitute the material for the production of bottled waters) varies. In view of the above, the type of water consumed is essential.


OBJECTIVE
The aim of the study was to estimate the calcium and magnesium contents in products available on the market and to evaluate calcium and magnesium consumption with natural mineral water by different consumer groups with an assumed volume of the consumed product.


MATERIAL AND METHODS
These represented forty different brands of natural mineral available waters on Polish market. These waters were produced in Poland or other European countries. Among the studied products, about 30% of the waters were imported from Lithuania, Latvia, Czech Republic, France, Italy and Germany. The content of calcium and magnesium in mineral waters was determined using flame atomic absorption spectrometry in an acetylene-air flame. Further determinations were carried out using atomic absorption spectrometer--ICE 3000 SERIES-THERMO-England, equipped with a GLITE data station, background correction (a deuterium lamp) as well as other cathode lamps.


RESULTS
Over half of the analysed natural mineral waters were medium-mineralized. The natural mineral waters available on the market can be characterized by a varied content of calcium and magnesium and a high degree of product mineralization does not guarantee significant amounts of these components. Among the natural mineral waters available on the market, only a few feature the optimum calcium-magnesium proportion (2:1). Considering the mineralization degree of the studied products, it can be stated that the largest percentage of products with significant calcium and magnesium contents can be found in the high-mineralized water group.


CONCLUSIONS
For some natural mineral waters, the consumption of 1 litre daily may ensure the recommended intake levels of calcium and magnesium in some consumer groups to a considerable degree. For 1-3-year-old children it is recommended to consume less than 1 litre daily of natural mineral waters containing an excess of 700 mg of calcium and 80 mg of magnesium in 1 litre.