Absorbability and utility of calcium in mineral waters.

BACKGROUND Calcium intake in North America remains substantially below recommended amounts. Bottled waters high in calcium could help close that gap. OBJECTIVES The objectives were to summarize and integrate published absorbability and biodynamic data concerning high-calcium mineral waters and to combine these data with hitherto unpublished analyses from my laboratory. DESIGN The usual library database was searched. The absorbability of calcium from a high-mineral water labeled with tracer quantities of (45)Ca was measured in human volunteers as a part of an otherwise low-calcium test meal. Published reports that used differing load sizes and meal conditions were harmonized by making corrections based on published calcium absorbability data. RESULTS All the high-calcium mineral waters had absorbabilities equal to milk calcium or slightly better. When tested, all produced biodynamic responses indicative of absorption of appreciable quantities of calcium (ie, increased urinary calcium, decreased serum parathyroid hormone, decreased bone resorption biomarkers, and protection of bone mass). CONCLUSION High-calcium mineral waters could provide useful quantities of bioavailable calcium.