Metabolic Effects of Drinking Mineral Waters

Analysis of drinking-water from the southern Aravah Rift Valley of Israel reveals a high sulphate, magnesium, calcium, and total dissolved solid content such that the water is outside the potable range as defined by the International Drinking Water Standards of the World Health Organization. Three villages in the Aravah region were studied where the water was high in salt content, and two outside the area where the water was sweet. The drinking of large volumes (7 to 20 litres/day) of mineral water in the southern and central Aravah was associated with a very high urine sulphate excretion: there was a moderate increase in urine calcium and magnesium excretion, with a highly significant correlation between sulphate excretion and sodium, calcium, magnesium, and total hydrogen ion excretion. Urine pH was inversely related to sulphate excretion and the urine of subjects in the Aravah was consistently highly acid and concentrated in summer, predisposing towards the formation of uric acid stones. The plasma calcium level was inversely related to sulphate and magnesium intake. Plasma magnesium was not related to magnesium intake. Plasma sulphate level elevated, in the range found in terminal renal failure. The high urinary magnesium excretion may prevent calcium stones. There is a mild, well-compensated metabolic acidosis in inhabitants ingesting brackish water in the southern Aravah in summer. Drinking-water standards should be based on quantities of salts ingested per day rather than merely on concentrations which have little relevance to daily intake.