Calcium
Calcium/Drug Interactions:
GeneralGeneral: Calcium may decrease absorption of various agents, including bisphosphonates, fluoroquinolone and tetracycline antibiotics, levothyroxine, phenytoin, and tiludronate disodium (91). AcetateAcetate: In humans, acetate enhanced calcium absorption from the human distal colon (221). AlcoholAlcohol: In women, alcohol consumption was inversely associated with calcium absorption (222). Alcohol may also inhibit enzymes in the liver that help convert vitamin D to its active form, which in turn reduces calcium absorption. The amount of alcohol required to affect calcium absorption is unknown. Aluminum-containing agentsAluminum-containing agents: In humans, calcium citrate increased intestinal aluminum absorption (112). According to secondary sources, citrate-containing preparations are contraindicated in chronic renal failure patients taking aluminum-containing compounds. AntacidsAntacids: According to a review, aluminum- and magnesium-containing antacids increase urinary calcium excretion (71). Use of proton pump inhibitors (esomeprazole) and calcium carbonate or calcium phosphate at the same time may cause decreased absorption of these calcium salts. AnticoagulantsAnticoagulants: In humans, citrate anticoagulation with calcium dialysate resulted in decreased anticoagulation (73). AnticonvulsantsAnticonvulsants: According to a review, anticonvulsants decreased calcium absorption by increasing the metabolism of vitamin D (71). In vitro and based on a review, anticonvulsant intake led to hypocalcemia and osteomalacia (74; 71). AntidiabeticsAntidiabetics: Interventional trials in nondiabetic participants using dairy products as a source of calcium demonstrated conflicting results, with the majority demonstrating a neutral effect on glucose parameters (223; 224; 225; 226; 227). According to a meta-analysis, combined data from two observational studies resulted in reduced incidence of type 2 diabetes (DM) in patients supplemented with calcium and vitamin D (152). In hypertensive and normotensive individuals (with and without diabetes), calcium improved insulin sensitivity (228; 76; 75). In women, an inverse relationship was established between calcium intake and plasma C-peptide, suggesting a decrease in insulin secretion (77). AntidotesAntidotes: According to secondary sources, use of sodium polystyrene sulfonate (SPS) should be avoided with nonabsorbable calcium. Calcium may be depleted with use of SPS, which may cause hypocalcemic tetany.AntihypertensivesAntihypertensives: In various patient populations, calcium has had effects on blood pressure, with the majority of studies suggesting decreases in blood pressure (229; 230; 231; 82; 81; 139; 134; 84; 232; 83; 233; 80; 148; 78; 79; 234). AntilipemicsAntilipemics: According to a review, cholestyramine may reduce the absorption of vitamin D, which, in turn, reduces the absorption of calcium (71). In healthy adults, dietary calcium supplementation affected bile acids, cholesterol, and its metabolites (85). In other populations, however, calcium supplementation had a lack of an effect on lipid profiles (86; 87; 84). BisphosphonatesBisphosphonates: According to a systematic review, aminobisphosphonates demonstrated the greatest effectiveness at maintaining normal calcium levels, and high dosages should be administered irrespective of baseline serum calcium (88). In humans, bisphosphonates normalized serum calcium levels (89). In humans, daily oral calcium and vitamin D demonstrated a lack of significant renal impairment or hypocalcemia with an intravenous zoledronate infusion compared with pamidronate (90). In men, alendronate in combination with calcium and vitamin D decreased vertebral fracture risk (235). Patients should take bisphosphonates on an empty stomach (91) at least 30 minutes before calcium. CaffeineCaffeine: According to secondary sources, caffeine may increase urinary calcium excretion, may affect calcium absorption, and has been implicated in osteoporosis; however, research is conflicting.Calcium channel blockersCalcium channel blockers: According to secondary sources, calcium, when given intravenously, may reverse the effects of calcium channel blockers, although conflicting evidence exists. Calcium channel blockers include nifedipine (Adalat?, Procardia?), verapamil (Calan?, Isoptin?, Verelan?), diltiazem (Cardizem?), isradipine (DynaCirc?), felodipine (Plendil?), and amlodipine (Norvasc?). Consult a qualified healthcare provider. In patients with supraventricular tachycardia, heart rate showed a lack of a significant change as a result of calcium pretreatment before verapamil infusion (92). Calcium saltsCalcium salts: According to secondary sources, combining calcium salts may increase absorption or alter efficacy.CeftriaxoneCeftriaxone: In infants, intravenous ceftriaxone and calcium-containing solutions may result in a life-threatening adverse drug reaction (113). Administering a total daily dose in a single administration, "push" administration, and using dosages higher than those approved by the U.S. Food and Drug Administration (FDA) may result in increased risk of a life-threatening adverse event. CorticosteroidsCorticosteroids: According to a review, glucocorticoids, such as prednisone, may cause calcium depletion and eventually osteoporosis when they are used for extended periods of time (91) DigoxinDigoxin: Intravenous calcium is frequently used to treat hyperkalemia. Calcium has been historically contraindicated in digoxin toxicity (110). In human research, however, there was a lack of support for the belief that calcium administration is contraindicated in patients with digoxin toxicity (111). Patients taking digoxin should consult with a qualified healthcare professional before using calcium supplements. DiureticsDiuretics: In humans, loop diuretics increased calcium excretion (191). In humans, thiazides and neutral potassium phosphate decreased urinary calcium levels (93). In patients with hypertension, idiopathic hypercalciuria, nonhypercalciuric urinary stone disease, and urinary stone disease with hypercalciuria, indapamide decreased calciuria (94). Dovonex?Dovonex?: According to secondary sources, calcipotriene (Dovonex?) may transiently increase calcium.FluorideFluoride: According to a review, combined use of fluoride and calcium may decrease the absorption of these minerals (71). However, these possible mineral interactions have not been shown to be of clinical significance. In humans, calcium prerinses increased one-hour salivary fluoride levels (236; 237). In patients with osteoporosis, low-dose fluoride administered with calcium over time decreased fracture rates compared to calcium monotherapy (238). GadoversetamideGadoversetamide: In patients receiving gadoversetamide, spurious hypocalcemia was observed in 20% of the sample (97). GentamicinGentamicin: According to secondary sources, gentamicin may decrease serum calcium.H2 antagonistsH2 antagonists: In humans, use of H2 blockers at the same time as calcium carbonate or calcium phosphate may interfere with the absorption of these calcium salts (98). Heart rate-regulating agentsHeart rate-regulating agents: In humans, intravenous calcium has been suggested as an effective measure against arrhythmias (239). In hypocalcemic patients, calcium therapy shortened repolarization intervals and decreased the number of ventricular premature complexes (72). According to secondary sources, calcium may form complexes with sotalol, reducing its absorption. Patients taking sotalol should consult a qualified healthcare professional before using calcium supplements to determine optimal timing of doses. Heavy metal antagonists/chelating agentsHeavy metal antagonists/chelating agents: In humans, sevelamer with calcium increased parathyroid hormone levels (240). A meta-analysis suggested that sevelamer has a lack of an effect on serum calcium (241). Hormonal agentsHormonal agents: In elderly women, low-dose continuous estrogen and progesterone therapy with calcium and vitamin D had a bone-sparing effect (242). This combination was purportedly well tolerated. InositolInositol: In animals, use of inositol hexaphosphate (phytic acid) decreased the absorption of calcium (99). Iron saltsIron salts: In humans, a broad variation in iron absorption was observed in the presence of calcium (100); other research has demonstrated a lack of an effect on absorption (102; 243). In humans, an increase in iron absorption was noted when milk or cheese were lacking in meals (101). The researchers suggested a reasonable separation of calcium and iron supplements or foods may improve iron uptake. LaxativesLaxatives: According to secondary sources, mineral oil and stimulant laxatives decrease calcium absorption.LithiumLithium: In a sample of patients taking lithium, a significant proportion developed hypercalcemia (103). MagnesiumMagnesium: According to secondary sources, combined use of magnesium and calcium may decrease the absorption of these minerals. However, these possible mineral interactions have not been shown to be of clinical significance. In humans, high calcium intake adversely affected magnesium utilization (105). OrlistatOrlistat: According to human research, orlistat (Xenical?) has been shown to induce a relative increase in bone turnover (increased resorption or bone loss), which may be due to the malabsorption of vitamin D and/or calcium (192). Additional human research has reported a lack of effect on calcium levels (193; 194). Oxalic acidOxalic acid: According to a review, calcium and oxalic acid or oxalate form a bond and cause nephrolithiasis (195). Parathyroid agentsParathyroid agents: In humans, cinacalcet lowered serum calcium concentrations (104). PhosphorusPhosphorus: According to secondary sources, calcium carbonate or acetate may be used effectively as phosphate binders.Potassium saltsPotassium salts: In humans, an inverse association was revealed between potassium and urinary calcium excretion and intestinal calcium absorption (106). A net change in calcium balance was lacking. PropionatePropionate: In humans, propionate enhanced calcium absorption from the human distal colon in a dose-dependent manner (221). QuinolonesQuinolones: Quinolone antibiotics include ciprofloxacin (Cipro?), gatifloxacin (Tequin?), gemifloxacin (Factive?), levofloxacin (Levaquin?), moxifloxacin (Avelox?), ofloxacin (Floxin?), fluoroquinolone, and others. In humans, ciprofloxacin's bioavailability decreased when coadministered with calcium acetate (95). The researchers concluded that clinical efficacy may be decreased and bacterial resistance to ciprofloxacin may increase with concomitant use. In humans, ciprofloxacin bioavailability decreased when administered with calcium-fortified orange juice (96). According to secondary sources, quinolones should be taken two hours before or 4-6 hours after calcium. TetracyclineTetracycline: According to secondary sources, intake of a tetracycline and calcium may decrease the absorption of the tetracycline, including doxycycline, minocycline, and tetracycline. Two to four hours between tetracyclines and calcium supplements should be allowed.ThyroxineThyroxine: According to secondary sources, intake of levothyroxine (Synthroid, Levothroid, Levoxyl) at the same time as calcium carbonate has been found to reduce levothyroxine absorption and to increase serum thyrotropin levels. Levothyroxine may adsorb to calcium carbonate in an acidic environment, which may block its absorption. Calcium and levothyroxine should be taken at least four hours apart. Thyroid agents and calcium should be administered four hours apart.Calcium/Herb/Supplement Interactions:
AcetateAcetate: In humans, acetate enhanced calcium absorption from the human distal colon (221). AlcoholAlcohol: In women, alcohol consumption was inversely associated with calcium absorption (222). Alcohol may also inhibit enzymes in the liver that help convert vitamin D to its active form, which in turn reduces calcium absorption. The amount of alcohol required to affect calcium absorption is unknown. Aluminum-containing agentsAluminum-containing agents: In humans, calcium citrate increased intestinal aluminum absorption (112). According to secondary sources, citrate-containing preparations are contraindicated in chronic renal failure patients taking aluminum-containing compounds. AntacidsAntacids: According to reviews, aluminum- and magnesium-containing antacids increase urinary calcium excretion (71). AntiarrhythmicsAntiarrhythmics: In humans, intravenous calcium has been suggested as an effective measure against arrhythmias (239). In hypocalcemic patients, calcium therapy shortened repolarization intervals and decreased the number of ventricular premature complexes (72). AnticoagulantsAnticoagulants: In humans, citrate anticoagulation with calcium dialysate resulted in decreased anticoagulation (73). AnticonvulsantsAnticonvulsants: According to a review, anticonvulsants decrease calcium absorption by increasing the metabolism of vitamin D (71). In vitro and according to review, anticonvulsant intake led to hypocalcemia and osteomalacia (74; 71). AntilipemicsAntilipemics: According to a review, antilipemics may reduce the absorption of vitamin D, which, in turn, reduces the absorption of calcium (71). In postmenopausal women, calcium plus vitamin D supplementation had a relatively small (?5%) change in lipids (274). In healthy adults, dietary calcium supplementation affected bile acids, cholesterol, and its metabolites (85). In other populations, however, calcium supplementation had a lack of an effect on lipid profiles (86; 87; 84). AstragalusAstragalus: In vitro, Drynol Cibotin, a combination product containing angelica, soy, wild yam, Ligustrum, astragalus, Cuscuta chinensis, Psoraleae corylifoliae, and Drynaria fortune, purportedly increased calcium uptake (275). CaffeineCaffeine: According to secondary sources, caffeine may increase urinary calcium excretion, may affect calcium absorption, and has been implicated in osteoporosis; however, research is conflicting.Calcium saltsCalcium salts: According to secondary sources, combining calcium salts may increase absorption or alter efficacy.Cuscuta chinensisCuscuta chinensis: In vitro, Drynol Cibotin, a combination product containing angelica, soy, wild yam, Ligustrum, astragalus, Cuscuta chinensis, Psoraleae corylifoliae, and Drynaria fortune, purportedly increased calcium uptake (275). DigoxinDigoxin: Intravenous calcium is frequently used to treat hyperkalemia. Calcium has been historically contraindicated in digoxin toxicity (110). In human research, however, there was a lack of support for the belief that calcium administration is contraindicated in patients with digoxin toxicity (111). Patients taking digoxin should consult with a qualified healthcare professional before using calcium supplements. DiureticsDiuretics: In humans, diuretics interacted with calcium levels (191; 93; 94). Dong quaiDong quai: In vitro, Drynol Cibotin, a combination product containing angelica, soy, wild yam, Ligustrum, astragalus, Cuscuta chinensis, Psoraleae corylifoliae, and Drynaria fortune, purportedly increased calcium uptake (275). Drynaria fortuneDrynaria fortune: In vitro, Drynol Cibotin, a combination product containing angelica, soy, wild yam, Ligustrum, astragalus, Cuscuta chinensis, Psoraleae corylifoliae, and Drynaria fortune, purportedly increased calcium uptake (275). Drynol CibotinDrynol Cibotin: In vitro, Drynol Cibotin, a combination product containing angelica, soy, wild yam, Ligustrum, astragalus, Cuscuta chinensis, Psoraleae corylifoliae, and Drynaria fortune, purportedly increased calcium uptake (275). FluorideFluoride: According to a review, combined use of fluoride and calcium may decrease the absorption of these minerals (71). However, these possible mineral interactions have not been shown to be of clinical significance. In humans, calcium prerinses increased one-hour salivary fluoride levels (236; 237). In patients with osteoporosis, low-dose fluoride administered with calcium over time decreased fracture rates compared to calcium monotherapy (238). Hormonal agentsHormonal agents: In elderly women, low-dose continuous estrogen and progesterone therapy with calcium and vitamin D had a bone-sparing effect (242). This combination was purportedly well tolerated. HypoglycemicsHypoglycemics: Interventional trials in nondiabetic participants using dairy products as a source of calcium demonstrated conflicting results, with the majority demonstrating a neutral effect on glucose parameters (223; 224; 225; 226; 227). According to a meta-analysis, combined data from two observational studies resulted in reduced incidence of type 2 diabetes (DM) in patients supplemented with calcium and vitamin D (152). In hypertensive and normotensive individuals (with and without diabetes), calcium improved insulin sensitivity (228; 76; 75). In women, an inverse relationship was established between calcium intake and plasma C-peptide, suggesting a decrease in insulin secretion (77). HypotensivesHypotensives: In various patient populations, calcium has had effects on blood pressure, with the majority of studies suggesting decreases in blood pressure (229; 230; 231; 82; 81; 139; 134; 84; 232; 83; 233; 80; 148; 78; 79; 234). InositolInositol: In animals, use of inositol hexaphosphate (phytic acid) decreased the absorption of calcium (99). Iron saltsIron salts: In humans, a broad variation in iron absorption was observed in the presence of calcium (100); other research has demonstrated a lack of an effect on absorption (102; 243). In humans, a statistically significant 30-50% increase in iron absorption was noted when milk or cheese were lacking in meals (101). The researchers suggested that a reasonable separation of calcium and iron supplements or foods may improve iron uptake. LaxativesLaxatives: According to secondary sources, mineral oil and stimulant laxatives (cascara, senna, and bisacodyl) decrease calcium and vitamin D absorption, often causing osteomalacia.LigustrumLigustrum: In vitro, Drynol Cibotin, a combination product containing angelica, soy, wild yam, Ligustrum, astragalus, Cuscuta chinensis, Psoraleae corylifoliae, and Drynaria fortune, purportedly increased calcium uptake (275). MagnesiumMagnesium: According to secondary sources, combined use of magnesium and calcium may decrease the absorption of these minerals. However, these possible mineral interactions have not been shown to be of clinical significance. In humans, high calcium intake adversely affected magnesium utilization (105). Oxalic acidOxalic acid: According to a review, calcium and oxalic acid or oxalate form a bond and cause nephrolithiasis (195). PhosphorusPhosphorus: According to secondary sources, calcium carbonate or acetate may be used effectively as phosphate binders.Potassium saltsPotassium salts: In humans, an inverse association was revealed between potassium and urinary calcium excretion and intestinal calcium absorption (106). A net change in calcium balance was lacking. PrebioticsPrebiotics: In animals (276) and humans (277), prebiotic use increased calcium absorption. In postmenopausal women, oligofructose-enriched inulin increased intestinal calcium absorption, improving mineral absorption and bone turnover impacting markers (278). ProbioticsProbiotics: In postmenopausal women, fermentation of milk with Lactobacillus helveticus benefited calcium metabolism (279). Psoraleae corylifoliaePsoraleae corylifoliae: In vitro, Drynol Cibotin, a combination product containing angelica, soy, wild yam, Ligustrum, astragalus, Cuscuta chinensis, Psoraleae corylifoliae, and Drynaria fortune, purportedly increased calcium uptake (275). Sodium alginateSodium alginate: According to secondary sources, intake of sodium alginate and calcium may decrease the absorption of calcium.SoySoy: In postmenopausal women, soy isoflavones had a lack of an effect on calcium metabolism (280). In vitro, Drynol Cibotin, a combination product containing angelica, soy, wild yam, Ligustrum, astragalus, Cuscuta chinensis, Psoraleae corylifoliae, and Drynaria fortune, purportedly increased calcium uptake (275). Uronic acidUronic acid: According to secondary sources, calcium may interact with uronic acid.Wild yamWild yam: In vitro, Drynol Cibotin, a combination product containing angelica, soy, wild yam, Ligustrum, astragalus, Cuscuta chinensis, Psoraleae corylifoliae, and Drynaria fortune, purportedly increased calcium uptake (275). ZincZinc: According to secondary sources, combined use zinc and calcium may decrease the absorption of these minerals. However, these possible mineral interactions have not been shown to be of clinical significance.Calcium/Food Interactions:
AlcoholAlcohol: In women, alcohol consumption was inversely associated with calcium absorption (222). Alcohol may also inhibit enzymes in the liver that help convert vitamin D to its active form, which in turn reduces calcium absorption. The amount of alcohol required to affect calcium absorption, however, is unknown. Alkaline dietAlkaline diet: According to a meta-analysis, promotion of the alkaline diet to prevent calcium loss is not justified (281). Caffeine-containing foodsCaffeine-containing foods: According to secondary sources, caffeine may increase urinary calcium excretion, may affect calcium absorption, and has been implicated in osteoporosis; however, research is conflicting.Carbonated beveragesCarbonated beverages: In humans, excess calciuria was associated with consumption of caffeinated carbonated beverages (282). Energy-reduced dietEnergy-reduced diet: In humans, an increased calcium intake appeared to enhance the benefits of energy restriction on obesity and high blood pressure (283). FiberFiber: In humans, mixed-food fiber had a lack of an effect on calcium balance when calcium intakes were high (?1.5g daily) (284). In subjects with type 2 diabetes, a high-fiber diet (50g total and 25g of soluble fiber) had a small impact on calcium balance (212). The researchers concluded that in patients consuming a high-fiber diet, adequate ingestion of calcium and other minerals may be necessary. FruitFruit: In humans, fruit intake reduced urinary calcium excretion (285). Iron-containing foodsIron-containing foods: In humans, a broad variation in iron absorption was observed in the presence of calcium (100); other research has demonstrated a lack of an effect on absorption (102; 243). In humans, a statistically significant 30-50% increase in iron absorption was noted when milk or cheese were lacking in meals (101). The researchers suggested a reasonable separation of calcium and iron supplements or foods may improve iron uptake. LactoseLactose: In lactose-tolerant, healthy adults, lactose had a lack of a beneficial effect on calcium bioavailability (286). In infants, however, lactose in an infant formula increased calcium absorption (287). Low-sodium dietLow-sodium diet: In humans, a low-salt diet reduced calcium excretion in hypercalciuric stone formers (288). Magnesium-containing foodsMagnesium-containing foods: In humans, high calcium intake adversely affected magnesium utilization (105). Oxalic acid-containing foodsOxalic acid-containing foods: According to a review, calcium and oxalic acid or oxalate form a bond and cause nephrolithiasis (195). Oxalic-acid containing foods include spinach, leeks, and collard greens. Phosphorus-containing foodsPhosphorus-containing foods: According to secondary sources, calcium carbonate or acetate may be used effectively as phosphate binders.Potassium-containing foodsPotassium-containing foods: In humans, an inverse association was revealed between potassium and urinary calcium excretion and intestinal calcium absorption (106). A net change in calcium balance was lacking. PrebioticsPrebiotics: In animals (276) and humans (277), prebiotic use increased calcium absorption. In postmenopausal women, oligofructose-enriched inulin increased intestinal calcium absorption, improving mineral absorption and bone turnover impacting markers (278). ProbioticsProbiotics: In postmenopausal women, fermentation of milk with Lactobacillus helveticus benefited calcium metabolism (279). ProteinProtein: According to a review and human research, the effect of protein intake on bone health is controversial, and there have been reports of increased calcium excretion with a high-protein diet (289; 290; 291). On the other hand, bone mineral density and bone mineral content (BMC) benefit from high protein intake. Studies have further demonstrated that protein intake had a lack of an effect on net loss of whole-body calcium (289; 292; 293). According to reviews, dietary protein and calcium work synergistically to increase calcium retention and bone metabolism (294; 295). In humans, hypocalciuria and secondary hyperparathyroidism occurred on a low-protein diet (296). In humans, a possible interaction between high-protein diets and calcium, and a subsequent reduced fat excretion has been suggested (297). SodiumSodium: In young girls, calcium retention was significantly reduced in response to salt loading (298). In individuals with a high sodium intake, an increase in calcium excretion was noted (299). Sodium alginateSodium alginate: According to secondary sources, intake of sodium alginate and calcium may decrease the absorption of calcium.SoySoy: In postmenopausal women, soy isoflavones had a lack of an effect on calcium metabolism (280). Zinc-containing foodsZinc-containing foods: According to secondary sources, combined use zinc and calcium may decrease the absorption of these minerals. However, these possible mineral interactions have not been shown to be of clinical significance.Calcium/Lab Interactions:
11-Hydroxycorticosteroids11-Hydroxycorticosteroids: According to secondary sources, intravenous calcium gluconate increased plasma 11-hydroxycorticosteroid concentrations.17-Hydroxycorticosteroids17-Hydroxycorticosteroids: According to secondary sources, intravenous calcium gluconate increased plasma 17-hydroxycorticosteroid concentrations.Bile acidsBile acids: In healthy adults, dietary calcium supplementation affected bile acids and animal neutral sterols (cholesterol and its metabolites) (85). Blood glucoseBlood glucose: Interventional trials in nondiabetic participants using dairy products as a source of calcium demonstrated conflicting results, with the majority demonstrating a neutral effect on glucose parameters (223; 224; 225; 226; 227). Blood lead levelsBlood lead levels: In lactating women, calcium supplementation demonstrated some benefit for lead toxicity (143). Blood lipidsBlood lipids: In postmenopausal women, calcium plus vitamin D supplementation resulted in a relatively small (?5%) change in lipids (274). In healthy adults, dietary calcium supplementation affected bile acids and animal neutral sterols (cholesterol and its metabolites) (85). In other populations, calcium supplementation had a lack of an effect on lipid profiles (86; 87; 84). Blood pressureBlood pressure: In varying patient populations, calcium affected blood pressure, with the majority of studies suggesting decreases in blood pressure (229; 230; 231; 82; 81; 139; 134; 84; 232; 83; 233; 80; 148; 78; 79; 234). Body weightBody weight: In human research, supplementation with calcium had a lack of a statistically or clinically significant effect on weight and body composition (300; 87; 141). Bone marker testsBone marker tests: According to a review, calcium supplementation had an effect on many bone remodeling biomarkers (301). In postmenopausal women, oligofructose-enriched inulin increased intestinal calcium absorption, improving mineral absorption and bone turnover impacting markers (278). In men, calcium supplementation suppressed bone resorption biochemical markers (302). In another study in healthy men, short-term high dietary calcium intake had a lack of an effect on bone turnover markers (303). In humans administered calcium supplements, a statistically significant difference (p<0.01) was detected between groups in the bone turnover markers pyridinoline (Pyr) and deoxypyridinoline (D-Pyr) levels (304). Other human research also indicated a reduced bone marker turnover after calcium supplementation (305; 306). Bone mineral densityBone mineral density: In postmenopausal women, high calcium intakes influenced bone mineral density and protected bone mass (307). CalciuriaCalciuria: In humans, calcium supplementation increased calciuria (306). In humans, loop diuretics increased calcium excretion (191). Coagulation panelCoagulation panel: In humans, citrate anticoagulation with calcium dialysate resulted in decreased anticoagulation (73). EstrogenEstrogen: In postmenopausal women, an association was established between dietary calcium and a change in estrogen metabolism toward the active 16-alpha-hydroxyl metabolic pathway (308). Fecal fatFecal fat: In humans, a 1,241mg daily increase in dairy calcium intake resulted in a 5.2g (1.6-8.8) increase in fecal fat daily (297). FerritinFerritin: In humans, a broad variation in iron absorption was observed in the presence of calcium (100), or there was a lack of an effect on absorption (102; 243). In humans, a statistically significant 30-50% increase in iron absorption was noted when milk or cheese were lacking in meals (101). GastrinGastrin: According to secondary sources, calcium carbonate increased serum gastrin concentrations within 30-75 minutes after administration.InsulinInsulin: For interventional trials, in hypertensive nondiabetics, calcium improved insulin sensitivity (228). In humans, calcium intake (not from dairy products) was associated with insulin sensitivity (75). In patients with hypertension and type 2 diabetes, calcium supplementation improved insulin sensitivity (76). In women, an inverse relationship was established between calcium intake and plasma C-peptide, suggesting a decrease in insulin secretion (77). LipaseLipase: According to secondary sources, calcium ions falsely decreased serum lipase concentration test results.MagnesiumMagnesium: In humans, high calcium intake adversely affected magnesium utilization (105). Parathyroid hormone (S-PTH)Parathyroid hormone (S-PTH): In humans, calcium supplementation or infusion reduced S-PTH (309; 310; 311; 312; 313). In pregnant women, low calcium intake was associated with increased systolic blood pressure and parathormone levels (79). Other human research also indicated decreased PTH was associated with calcium supplementation (314). In Indian toddlers, low dietary calcium intake was associated with PTH resistance (315). PhosphorusPhosphorus: According to secondary sources, calcium carbonate or acetate may be used effectively as phosphate binders. Use may increase calcium phosphate products in blood.Placental blood flowPlacental blood flow: In pregnant women administered calcium supplements, average umbilical and uterine artery resistance index and pulsatility index tended to be lower (202). QT intervalQT interval: In hypocalcemic patients, calcium therapy shortened repolarization intervals and decreased the number of ventricular premature complexes (VPCs) (72). Serum calciumSerum calcium: In humans, a higher intake of calcium is generally associated with higher serum calcium levels (316; 314). Urinary oxalateUrinary oxalate: In hyperoxaluric patients with kidney stones, dietary calcium reduced urinary oxalate (317). In women with renal calcium calculi, calcium citrate supplementation decreased urinary calcium oxalate saturation (117).