Fewer biochemical markers and measures of calcium metabolism are available. Attempts to identify a calcium status indicator in blood have been unsuccessful. Serum calcium exists in three fractions: protein-bound, ionized, and complexed. The protein-bound calcium is considered physiologically inactive, whereas the ionized fraction is considered physiologically active and functions as an intracellular regulator. Complexed calcium is complexed with small negative ions, such as citrate, phosphate, and lactate. Its biological role is uncertain. Urinary Calcium Urinary calcium levels are more responsive to changes in dietary calcium intake than are serum levels. However, urinary calcium is affected by a number of other factors ,including those factors leading to hypercalcemia. When serum levels are high, more calcium is available to be excreted through the urine. There is a diurnal variation in urinary calcium, with concentrations higher during the day and lower in the evening. Calcium output tends to be increased when the diet is rich in dietary protein and is low in phosphate and tends to be decreased by high- protein diets rich in phosphate. Urinary calcium losses are increased when the volume of urine output is high and when the kidneys’ ability to reabsorb calcium is impaired. Hypocalciuria can result from those factors leading to hypocalcemia as well as from renal failure. Use of the ratio of calcium to creatinine calculated from 2-hour fasting urine samples has been suggested as a possible indicator of calcium status hut requires further research. The calcium level in an overnight urine sample shows potential as an indicator of compliance with calcium supplementation. ZINC STATUS Zinc’s most important physiologic function is as a component of numerous enzymes. Consequently. zinc is involved in many metabolic processes, including protein synthesis. wound healing, immune function, and tissue growth and maintenance. Severe zinc deficiency characterized by hypogonadism and dwarfism has been observed in the Middle East.
Fewer biochemical markers and measures of calcium metabolism are available. Attempts to identify a calcium status indicator in blood have been unsuccessful. Serum calcium exists in three fractions: protein-bound, ionized, and complexed. The protein-bound calcium is considered physiologically inactive, whereas the ionized fraction is considered physiologically active and functions as an intracellular regulator. Complexed calcium is complexed with small negative ions, such as citrate, phosphate, and lactate. Its biological role is uncertain. Urinary Calcium Urinary calcium levels are more responsive to changes in dietary calcium intake than are serum levels. However, urinary calcium is affected by a number of other factors ,including those factors leading to hypercalcemia. When serum levels are high, more calcium is available to be excreted through the urine. There is a diurnal variation in urinary calcium, with concentrations higher during the day and lower in the evening. Calcium output tends to be increased when the diet is rich in dietary protein and is low in phosphate and tends to be decreased by high- protein diets rich in phosphate. Urinary calcium losses are increased when the volume of urine output is high and when the kidneys’ ability to reabsorb calcium is impaired. Hypocalciuria can result from those factors leading to hypocalcemia as well as from renal failure. Use of the ratio of calcium to creatinine calculated from 2-hour fasting urine samples has been suggested as a possible indicator of calcium status hut requires further research. The calcium level in an overnight urine sample shows potential as an indicator of compliance with calcium supplementation. ZINC STATUS Zinc’s most important physiologic function is as a component of numerous enzymes. Consequently. zinc is involved in many metabolic processes, including protein synthesis. wound healing, immune function, and tissue growth and maintenance. Severe zinc deficiency characterized by hypogonadism and dwarfism has been observed in the Middle East.