- Discussion:
    - calcium requirements:
         - age  1 - 10:  800-1000 mg per day;
         - age 11 - 35: 1200 mg per day;
         - premenopausal:  1000 mg per day;
         - postmenopausal: 1500 mg per day;
         - fracture healing: 1500 mg per day;
         - pregnancy: 1500 mg per day:
         - lactation: 2000 mg per day;
    - absorption characteristics:
         - approximately 20% of oral calcium is absorbed by the gut under normal conditions;
         - requires physiologic gastric acidity and normal bowel and pancreatic funciton;
         - in order to optimize absorption, give divided doses of calcium supplements throughout the day (doses less than 500 mg per dose);
         - excessive phosphorous (as in soft drinks) binds Ca and prevents absorption;
         - gastro-intestinal causes of osteomalacia:
                - excessive fatty acids bind calcium and prevent absorption;
                - phytic acids (found in wheat and tea);
    - calcium content of various supplements:
         - 8 oz of milk: 250-300 mg (and also contains 100 international units of vitamin D);
         - 1 gm of calcium is present in  2.5 gm of calcium carbonate;
         - 1 gm of calcium is present in  5.0 gm of calcium citrate;
         - 1 gm of calcium is present in  8.0 gm of calcium lactate;
         - 1 gm of calcium is present in 10.0 gm of calcium gluconate;
         - calcium citrate:
                 - preferred form of supplementation;
                 - will reduce kidney stones (citrate binds to oxalate which reduces its intestinal absorption)
         - phoslo
                - calcium acetate: 667 MG
                - calcium acetate anhydrous 667 MG = Calcium 169 M
         - calcium carbonate:
                - Os-Cal 250 = 625mg calcium carbonate (each tab contains 250mg of elemental calcium and 125 USP units of Vit D);
                - Os-Cal 500 = 1250 mg calcium carbonate (each tab contains 500mg of elemental calcium);
                - Os-Cal Forte = 250mg elemental calcium plus vitamins and minerals;
                - CaCO3 650mg PO tid/qid is good for slowing diarrhea induced by tube feeding;
                - for calcium replacment: Adults: 500mg PO qd or 1 tab tid;
                - note that there is reduced calcium absorption from medications that reduce stomach acid (prilosec);
                       - calcium carbonate requires a low pH for salt dissociation;
         - cal-bid: calcium supplement w/ Vit C and D added
                - 625 mmg (= 250 mmg elemental calcium);

- Phosporous Requirements:
    - daily requirement of phosphorous is 1000 mg;
    - 75% is absorbed in the gut

The beneficial role of calcium supplementation during resuscitation from shock.

Original Article: Effect of the Time of Administration of Calcium Acetate on Phosphorus Binding.