Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT01815021. Get the latest research information from NIH: You have reached the maximum number of saved studies (100). If none of the conversion formulas (a-c, I-Day 7) resulted in serum calcium values within the desired target range (7.0-10.0 mg/dL), the study will be terminated. 50% of the initial daily supplementation of CCS will be replaced by ACC based on the conversion factor found in I-day 7 (formulas a-c): Conversion factor 0.5: 50% (in mg, calculated out of the initial total daily intake) of elemental calcium will be replaced by 25% of elemental calcium from ACC (in mg, calculated out of the initial total daily intake). In addition, preclinical animal research has shown that amorphous calcium is the … Subjects will be reminded to take the calcium supplementation according to their assignment instructions. Calculation of albumin corrected calcium (CA) will be performed. Phase II To test the hypothesis that treatment with smaller doses of elemental calcium from ACC compared to CCS can maintain target serum calcium (corrected for albumin) values (7.0-10.0 mg/dL). Choosing to participate in a study is an important personal decision. Calculation: Calcium (corrected, mmol/L) = Calcium (measured, mmol/L) + {(40 - albumin(g/L)) x 0.02}. Over the following 24 h subjects will consume meals that will be selected by the Unit of Clinical Nutrition at Sourasky Medical Center nutritionist on the basis of their food diary and ALL urine excreted during this time should be collected in a designated urine container and returned to the Unit of Clinical Nutrition at Sourasky Medical Center for evaluation. Standard-of-care (CCS) - The same elemental calcium dosage that was used routinely prior to the study. U.S. Department of Health and Human Services, The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Why Should I Register and Submit Results? A single case showed that when taken on an empty stomach, amorphous calcium carbonate absorption in the intestine was 4.6-folds higher than crystalline calcium carbonate. Subjects will be asked about symptoms and signs related with a change in serum calcium levels (tetany, facial grimacing, paresthesias, muscle aches, arrhythmia, depression). The calculation for the number of tablets per day will be performed specifically for each subject (according to the daily dosage of calcium supplementation) by the doctor. If CA levels are below 7.0 mg/dl, or above 10.0 mg/dl, subject will be excluded from the study (based on the doctor's decision). Subjects will be asked about symptoms and signs related with a change in serum calcium levels (tetany, facial grimacing, paresthesias, muscle aches, arrhythmia, depression). II-Day 56 (±1): Subjects will arrive at the Clinical Research Center and their serum calcium, P and albumin levels will be tested. Subjects who provide written informed consent to participate in the study. These include chalk, limestone, marble and Iceland spar for a start. Subjects will be asked about any side effects or AEs that may have occurred and changes in concomitant medications since their last visit. Subjects will receive instructions regarding the new doses of ACC and will be reminded to take XXX capsules a day, XXX in the morning, XXX in midday and XXX in the evening, before or after a meal (based on their initial assignment). NTDC = ITDC - [0.2×ITDC (mg CCS)] + [0.1×ITDC (mg ACC)]. Dietary Supplement: amorphous calcium carbonate, Dietary Supplement: crystalline calcium supplements. Information provided by (Responsible Party): 50, 100 and 200 mg elemental calcium tablets, according to the doctor's decision, Tablets, according to the doctor's decision, The serum phosphorus test measures the amount of phosphate in the blood. Phase II Ten (10) subjects previously diagnosed and chronically treated for primary hypoparathyroidism will be enrolled. For general information, Learn About Clinical Studies. Subjects will be asked about symptoms and signs related with a change in serum calcium levels (tetany, facial grimacing, paresthesias, muscle aches, arrhythmia, depression). Amorphous Calcium Carbonate (Acc) Versus Crystalline Calcium Carbonate (Ccc) Using Stable Calcium Isotopes In Postmenopausal Women. Subjects will be asked to fill out a food and medication diary for 3 consecutive days to evaluate their daily dietary calcium intake. Calculation of CA will be performed. The study is comprised of 15 subjects orally administered immediately after breakfast a 600 mg gelatin capsules containing either 600 mg (2 capsules of 300 mg)of ACC (192 mg elemental calcium) of 480 mg CCC (192 mg elemental calcium), labeled with 15 mg of 44Ca (2 capsules of 300 mg). Report: Hank Williams Jr. removed from 'MNF' intro Calculation of CA will be performed. Calculation CA at baseline will be performed. A Randomized, Two Phase, Adaptive Then Crossover Open-label, Study Comparing Amorphous Calcium Carbonate (ACC) Supplement Versus Commercially Available Crystalline Calcium Supplements (CCS) in the Management of Primary Hypoparathyroidism. Eligible subjects will be treated as follows: Phase I Ten (10) subjects previously diagnosed and chronically treated for primary hypoparathyroidism will be enrolled. NTDC = ITDC - [0.1×ITDC (mg CCS)] + [0.075×ITDC (mg ACC)] CA <7.00 mg/dl will enforce end of treatment. Subjects previously assigned to the ACC treatment arm, will be instructed to resume their regular CCS supplementation. II-Day 35 (±1): Subjects will arrive to the Clinical Research Center and their serum calcium, P and albumin levels will be tested. NTDC = ITDC - [0.1×ITDC (mg CCS)] + [0.025×ITDC (mg ACC)] Subjects will be asked about any side effects or AEs that may have occurred and changes in concomitant medications since their last visit.