Concentration of dietary calcium supplied by calcium carbonate does not affect the apparent total tract digestibility of calcium, but decreases digestibility of phosphorus by growing pigs. Particle size of calcium carbonate does not affect apparent and standardized total tract digestibility of calcium, retention of calcium, or growth performance of growing pigs. Effects of microbial phytase on apparent and standardized total tract digestibility of calcium in calcium supplements fed to growing pigs. Estimation of true phosphorus digestibility and endogenous phosphorus loss in growing pigs fed conventional and low-phytate soybean meals. Requirement for digestible calcium by 25 to 50 kg pigs at different dietary concentrations of phosphorus as indicated by growth performance, bone ash concentration, and calcium and phosphorus balances. Calcium intake in health maintenance – a systematic review Effect of Dairy and Nondairy Calcium on Fecal Fat Excretion in Lactose Digester and Maldigester Obese Adults A diet high in meat protein and potential renal acid load increases fractional calcium absorption and urinary calcium excretion without affecting markers of bone resorption or formation in postmenopausal women. Calcium supplements and milk: effects on acid-base balance and on retention of calcium, magnesium, and phosphorus. Sources of evidence for systematic reviews of interventions in diabetes.
A regional experiment was conducted to test the hypothesis that the concentration of dietary Ca does not affect the digestibility of Ca or P in diets fed to growing pigs .  Six diets based on corn , potato protein isolate , cornstarch , and soybean oil were formulated . All diets also contained monosodium phosphate , crystalline AA , salt , and a vitamin-micromineral premix . The only difference among the diets was that varying concentrations of calcium carbonate were used to create diets containing 0.33 , 0.46 , 0.51 , 0.67 , 0.92 , and 1.04 % Ca . All diets contained between 0.40 and 0.43 % P. Six universities participated in the experiment and each university contributed 2 replicates to the experiment for a total of 12 replicates ( initial BW : 23.1 ± 4.4 kg ) . Pigs were placed in metabolism cages that allowed total , but separate , collection of feces and urine from the pigs . Pigs within each replicate were r and omly allotted to the 6 diets and fed experimental diets for 14 d with urine and feces being collected over a 5-d period . Diets , feces , and urine sample s were analyzed for Ca and P , and the daily balance , the apparent total tract digestibility ( ATTD ) , and the retention of Ca and P were calculated . Results indicated that intake , fecal excretion , and urinary excretion of Ca increased ( linear , P<0.05 ) as dietary Ca concentration increased . The daily intake of P was not affected by the dietary concentration of Ca , but fecal excretion of P increased ( linear , P<0.05 ) as dietary Ca concentrations increased . In contrast , urinary P output was decreased ( linear , P<0.05 ) as dietary Ca increased . The retention of Ca increased ( linear , P<0.05 ) from 1.73 to 4.60 g/d , whereas the retention of P decreased ( linear , P<0.05 ) from 1.98 to 1.77 g/d as dietary Ca concentrations increased . However , if calculated as a percentage of intake , both Ca and P retention were decreased ( linear , P<0.05 ) as dietary Ca concentration increased ( from 55.4 to 46.1 % and from 48.4 to 43.5 % , respectively ) . The ATTD of Ca was not affected by the dietary concentration of Ca , but the ATTD of P was decreased ( linear , P<0.05 ) from 56.9 to 46.2 % as dietary Ca concentration increased . It is concluded that the dietary concentration of Ca does not affect the ATTD of Ca in calcium carbonate , but increased concentrations of dietary Ca may decrease the ATTD of P in diets based on corn , potato protein isolate , and monosodium phosphate Two experiments were conducted to evaluate particle size of calcium carbonate used in diets fed to growing pigs . Experiment 1 was conducted to determine apparent total tract digestibility ( ATTD ) , st and ardized total tract digestibility ( STTD ) , and retention of Ca among diets containing calcium carbonate produced to different particle sizes , and Exp . 2 was conducted to determine if growth performance of weanling pigs is affected by particle size of calcium carbonate . In Exp . 1 , 4 diets based on corn and potato protein isolate were formulated to contain 0.70 % Ca and 0.33 % st and ardized total tract digestible P , but the calcium carbonate used in the diets was ground to 4 different particle sizes ( 200 , 500 , 700 , or 1,125 μm ) . A Ca-free diet was formulated to determine basal endogenous losses of Ca . In Exp . 2 , 4 diets were based on corn and soybean meal and the only difference among diets was that each diet contained calcium carbonate ground to the 4 particle sizes used in Exp . 1 . In Exp . 1 , 40 barrows ( 15.42 ± 0.70 kg initial BW ) were allotted to the 5 diets with 8 replicate pigs per diet using a r and omized complete block design , and in Exp . 2 , 128 pigs with an initial BW of 9.61 ± 0.09 kg were r and omly allotted to 4 experimental diets . Results of Exp . 1 indicated that basal endogenous losses of Ca were 0.329 g/kg DMI . The ATTD of Ca was 70.0 ± 3.2 , 74.3 ± 2.7 , 70.0 ± 2.9 , and 72.1 ± 2.7 and the STTD of Ca was 74.2 ± 3.2 , 78.5 ± 2.7 , 74.1 ± 2.9 , and 76.2 ± 2.7 for calcium carbonate ground to 200 , 500 , 700 , or 1,125 μm , respectively . Retention of Ca was 67.4 ± 3.1 , 70.4 ± 2.6 , 63.9 ± 2.8 , and 67.2 ± 2.2 for diets containing calcium carbonate ground to 200 , 500 , 700 , or 1,125 μm , respectively . There were no differences among diets for ATTD of Ca , STTD of Ca , or retention of Ca . The ATTD of P was 64.5 ± 1.7 , 66.8 ± 2.6 , 64.2 ± 3.0 , and 63.2 ± 1.7 % and retention of P was 61.4 ± 1.4 , 63.8 ± 2.8 , 61.9 ± 2.8 , and 60.9 ± 1.5 for diets containing calcium carbonate ground to 200 , 500 , 700 , or 1,125 μm , respectively . Neither ATTD of P nor retention of P was influenced by the particle size of calcium carbonate . Results of Exp . 2 indicated that ADG , ADFI , and G : F were not impacted by the particle size of calcium carbonate . In conclusion , particle size of calcium carbonate did not affect ATTD of Ca , STTD of Ca , or retention of Ca ; ATTD of P or retention of P ; or growth performance of pigs . Any particle size of calcium carbonate in the range from 200 to 1,125 μm can therefore be used in diets fed to pigs An experiment was conducted to test the hypothesis that differences in the apparent total tract digestibility ( ATTD ) and st and ardized total tract digestibility ( STTD ) of Ca exist among Ca supplements and that inclusion of microbial phytase increases the ATTD and STTD of Ca . One hundred and four growing barrows ( average initial BW of 17.73 ± 2.53 kg ) were allotted to a r and omized complete block design with 13 dietary treatments and 8 pigs per treatment . A basal diet containing corn , cornstarch , potato protein isolate , soybean oil , calcium carbonate , monosodium phosphate , vitamins , and minerals was formulated . Five additional diets were formulated by adding monocalcium phosphate ( MCP ) , dicalcium phosphate ( DCP ) , calcium carbonate , Lithothamnium calcareum Ca , or a high-Ca sugar beet co-product to the basal diet at the expense of cornstarch . Six additional diets that were similar to the previous 6 diets with the exception that they also contained 500 units per kilogram of microbial phytase were also formulated . A Ca-free diet was used to determine basal endogenous losses of Ca . Feces were collected using the marker-to-marker approach . Results indicated that regardless of inclusion of microbial phytase , MCP had the greatest ( P < 0.05 ) ATTD and STTD of Ca . The ATTD and STTD of Ca in DCP were greater ( P < 0.05 ) than in calcium carbonate , L. calcareumC a , or in the sugar beet co-product , but no differences were observed among the ATTD and STTD of Ca in calcium carbonate , L. calcareum Ca , or sugar beet co-product . Inclusion of microbial phytase increased ( P < 0.05 ) the ATTD and STTD of Ca in the diets , but this was not the case in the Ca supplements . Regardless of inclusion of microbial phytase , the ATTD of P was greater ( P < 0.05 ) in pigs fed basal , MCP , or DCP diets than in pigs fed calcium carbonate , L. calcareum Ca , or the sugar beet co-product , but pigs fed calcium carbonate diets had greater ( P < 0.05 ) ATTD of P than pigs fed L. calcareumCa or the sugar beet co-product . Regardless of Ca source , inclusion of microbial phytase increased ( P < 0.001 ) the ATTD of P. In conclusion , MCP has the greatest ATTD and STTD of Ca  among the calcium supplements used in this experiment , followed by DCP . Basal , MCP , and DCP diets had greater ATTD of P than the other diets , and inclusion of microbial phytase increased the ATTD and STTD of Ca and the ATTD of P in the diets This study reevaluated the method of regressing of total P output against dietary P intake to simultaneously estimate true P digestibility and endogenous P loss in growing pigs fed either conventional or low-phytate soybean meal ( SBM ) . Four isocaloric diets were formulated to contain increasing concentrations of each type of SBM ( 8 diets total ) , and therefore contained increasing concentrations of dietary P. Dietary P and Ca concentrations were deficient because they were supplied solely by SBM , and Ca : total P ratios were less than 1:1 . Sixteen barrows ( initial BW 17.7 + /- 1.8 kg ) were surgically fitted with a simple T-cannula at the distal ileum , r and omly assigned to metabolism crates , and fed the experimental diets in a replicated 8 x 8 Latin square design . Feed was provided at 90 g/kg of BW(0.75 ) and fed in 2 equally sized meals at 0800 and 2000 , with diets containing Cr sesquioxide ( 3 g/kg ) as an indigestible marker . As the P concentration increased from 0.9 to 3.9 g/kg of DM , the apparent prececal P digestibility increased for conventional SBM ( P < 0.05 ) , but no relationship was observed for low-phytate SBM . The output of total P [ mg/(kg of BW(0.75).d ) ] , either prececal or total tract , exhibited a linear relationship ( P < 0.01 ) with increasing P intake . However , a quadratic response ( P = 0.02 ) was also detected for total tract P output from pigs fed low-phytate SBM . True P digestibility was not different between prececal and total tract collection sites ( P > 0.10 ) , but was greater ( P < 0.01 ) for low-phytate SBM ( 62.6 % ) compared with conventional SBM ( 44.5 % ) . Endogenous P estimates were not different between the SBM varieties and averaged 4.83 mg/(kg of BW(0.75).d ) . However , endogenous P estimates were highly variable between individual animals and , therefore , were not significantly different from zero . In this study , estimates of endogenous P loss from pigs were relatively low compared with previously reported values , and evidence of nonlinearity in P output was observed . These results suggest that the difference in true P digestibility between conventional SBM and low-phytate SBM is influenced by dietary phytate content when growing pigs are fed P-deficient diets Two experiments were conducted to determine the requirement for st and ardized total tract digestible ( STTD ) Ca by 25 to 50 kg pigs at different concentrations of STTD P. Twenty corn-soybean meal based diets were formulated with diets containing 4 concentrations of STTD P ( 0.15 , 0.31 , 0.39 , or 0.47 % ) and 5 concentrations of STTD Ca ( 0.13 , 0.27 , 0.42 , 0.57 , or 0.72 % ) . Diets were mixed in 1 batch and were used in both experiments . In Exp . 1 , 240 pigs ( initial average BW : 24.70 ± 1.27 kg ) were r and omly allotted to the 20 diets in 6 blocks with 1 pen per diet in each block using a 4 × 5 factorial design . There was 1 gilt and 1 barrow in each pen . At the conclusion of the 28 d experiment , all barrows were euthanized and the right femur was collected . Results indicated that there were interactions ( < 0.001 ) between concentration of STTD Ca and concentration of STTD P in diets for ADG , G : F , and bone ash . The predicted maximum ADG at STTD P concentrations of 0.15 , 0.31 , 0.39 , and 0.47 % were 0.76 , 0.87 , 0.90 , and 0.92 kg at STTD Ca concentrations of 0.12 , 0.36 , 0.47 , and 0.59 % , respectively , which correspond to STTD Ca : STTD P ratios of 0.80:1 , 1.16:1 , 1.21:1 , and 1.26:1 . The predicted maximum G : F ratio at the 4 STTD P concentrations were 0.43 , 0.46 , 0.48 , and 0.50 kg/kg at STTD Ca concentrations of 0.09 , 0.38 , 0.52 , and 0.67 % , respectively , and these values correspond to STTD Ca : STTD P ratios of 0.60:1 , 1.23:1 , 1.33:1 , and 1.43:1 . The predicted maximum bone ash at the 4 STTD P concentrations were 14.5 , 21.0 , 23.1 , and 24.5 g at STTD Ca concentrations of 0.41 , 0.56 , 0.64 , and 0.72 % , respectively , which correspond to STTD Ca : STTD P ratios of 2.73:1 , 1.81:1 , 1.64:1 , and 1.53:1 . In Exp . 2 , 120 pigs ( initial average BW : 29.45 ± 2.15 kg ) were placed in metabolism crates and r and omly allotted to the 20 diets in 6 blocks with 1 pig per diet in each block . Fecal and urine sample s were collected . Results indicated that the predicted maximum retention of Ca in the body at STTD P concentrations of 0.15 , 0.31 , 0.39 , and 0.47 % were 4.7 , 7.1 , 8.6 , and 10.2 g/d at STTD Ca concentrations of 0.77 , 0.96 , 1.06 , and 1.15 % , respectively , which correspond to STTD Ca : STTD P ratios of 5.13:1 , 3.10:1 , 2.72:1 , and 2.45:1 . These observations indicate that if STTD P meets or exceeds the requirement , the STTD Ca : STTD P ratio needed to maximize ADG and G : F by 25 to 50 kg pigs is between 1.16:1 and 1.43:1 . However , a greater ratio may be needed to maximize bone ash or Ca retention Background Calcium ( Ca ) is an essential nutrient for the human body . Despite lively research , there is uncertainty about Ca requirements in terms of desirable health outcomes including an upper intake level above which the potential for harm increases . Objectives The aim was to conduct a review to up date requirements and desirable or harmful health effects of Ca on the current scientific evidence . Methods We search ed Medline and Swemed from January 2000 to December 2011 and included all systematic review s that reported Ca supplementation or usual Ca intake on health outcomes . Meta-analyses , r and omized clinical trials and cohort studies were included in the second search between May 2009 and March 2011 and an additional search covering studies till the end of 2011 . This review concentrated on studies reporting independent effects of Ca , although a few recent trials report sole effects of Ca on health outcomes , most trials use Ca in combination with vitamin D vs. placebo . Results In total , we review ed 38 studies addressing the effects of Ca on bone , pregnancy-related outcomes , cancers , cardiovascular outcomes , obesity , and mortality .  There was a lot of heterogeneity in the study protocol s , which made it difficult to draw any strong conclusions . According to the literature , high Ca intake seems to have a small positive effect on bone mineral content ( BMC ) or bone mineral density ( BMD ) in children and postmenopausal women . We did not find any consistent evidence on the effects of Ca on bone health in premenopausal women or men . Also , the evidence that Ca supplementation reduces fracture incidence is scarce and inconsistent . Maternal diet may influence the peak bone mass of offspring but more studies are required . There was no overall effect of Ca intake on cancers . Ca was associated with a decreased risk of breast cancer and a slightly increased risk of prostate cancer in two of the three studies . No associations were found with other cancers . We found no consistent association between cardiovascular outcomes and  Ca  intake except for blood pressure . A small decrease of 2–4 mmHg in systolic blood pressure was found in pregnant and in hypertensive subjects with Ca supplementation . Review ed studies did not show consistent evidence relating Ca intake to either mortality or obesity . Conclusion Based on this evidence , there is no need to change the Nordic recommendations for Ca intake . However , due to heterogeneity in the studies it is difficult to interpret the results and provide single summary statement Background : The effect of dietary calcium ( Ca ) on fecal fat excretion in lactose maldigestion is not known . Objective : To investigate the effect of dairy and non-dairy dietary Ca on fecal fat excretion in lactose digesters and maldigesters during moderate energy restriction . Design : A r and omized cross-over trial comparing the effect of 500 mg versus 1500 mg dairy and non-dairy Ca on fecal fat excretion in 34 healthy adults during moderate ( −30 % ) energy restriction induced weight loss for 12 weeks . The participants were classified as lactose digester or maldigester on the basis of breath hydrogen test . Measurements : Anthropometric parameters and body composition , resting energy expenditure , energy and nutrient intake , fecal fat , physical activity , blood pressure , blood and urine sampling for pertinent measurements . Results : Fecal fat loss expressed as percent of fat intake was significantly higher with 1500 mg ( high Ca ) as compared with 500 mg ( low Ca ) Ca intake per day ( mean : 3.0 % ; 95 % CI : 2.3 to 3.7 % ; P<0.001 ) independent of Ca source and lactose digestion status . Conclusions : During a moderate energy restriction induced weight loss , a high-Ca diet causes an increase in fecal fat excretion independent of Ca source . Ca intake related fecal fat loss is also independent of the ability to digest lactose and it is not diminished over time ( US Clinical Trial Registration : Clinical trials.gov NCT00808275 Our objective in this study was to determine the effects of a high-protein and high-potential renal acid load ( PRAL ) diet on calcium ( Ca ) absorption and retention and markers of bone metabolism . In a r and omized crossover design , 16 postmenopausal women consumed 2 diets : 1 with low protein and low PRAL ( LPLP ; total protein : 61 g/d ; PRAL : -48 mEq/d ) and 1 with high protein and high PRAL ( HPHP ; total protein : 118 g/d ; PRAL : 33 mEq/d ) for 7 wk each separated by a 1-wk break . Ca absorption was measured by whole body scintillation counting of radio-labeled (47)Ca . Compared with the LPLP diet , the HPHP diet increased participants ' serum IGF-I concentrations ( P < 0.0001 ) , decreased serum intact PTH concentrations ( P < 0.001 ) , and increased fractional (47)Ca absorption ( mean ± pooled SD : 22.3 vs. 26.5 ± 5.4 % ; P < 0.05 ) and urinary Ca excretion ( 156 vs. 203 ± 63 mg/d ; P = 0.005 ) . The net difference between the amount of Ca absorbed and excreted in urine did not differ between 2 diet periods ( 55 vs. 28 ± 51 mg/d ) . The dietary treatments did not affect other markers of bone metabolism . In summary , a diet high in protein and PRAL  increases the fractional absorption of dietary Ca , which partially compensates for increased urinary Ca , in postmenopausal women . The increased IGF-I and decreased PTH concentrations in serum , with no change in biomarkers of bone resorption or formation , indicate a high-protein diet has no adverse effects on bone health The effect of supplementing a basal diet containing 697 mg calcium daily ( 17.4 mmol/d ) with an additional 900 mg Ca daily from milk , Ca chloride , or a Ca carbonate preparation was examined in eight adult males during a 56-d metabolic balance study . The ingestion of the milk or Ca supplements had no overall effect on Ca retention by these subjects because the milk and supplements depressed apparent absorption of Ca in the gut and fractional tubular reabsorption of Ca in the kidneys . Supplementation of the diet with CaCl and to a lesser extent with milk significantly increased renal acid excretion whereas supplementation with CaCO3 depressed renal acid excretion . The three Ca supplements significantly altered magnesium and phosphorus absorption and urinary excretion in different manners but had no overall effect on retention of P or Mg . The responses of our subjects to these treatments may be different than those of subjects who are chronically in negative balance in regard to Ca AIMS To analyse the effect on systematic review s in diabetes interventions of including only trials that are indexed in medline , and to assess the impact of adding trials from other data bases and the grey literature . METHODS All systematic review s of diabetes interventions which included a meta- analysis of r and omized controlled trials , and were published since 1996 , were selected . The impact on the meta- analysis of including only those trials indexed in medline , and the effect of then adding trials from other sources , was assessed . Where possible this was measured quantitatively , by redoing the meta- analysis , otherwise a qualitative estimate was made . RESULTS Forty-four systematic review s met our inclusion criteria . There were 120 articles reporting trial data which were not indexed in medline . These came from 52 % of the review s. In 34 % of the review s , basing a meta- analysis on a search of only medline would miss trials that could affect the result . Sources of non- medline data which had the biggest effect on the meta-analyses were journal articles from central and embase ( mainly in Diabetes , Nutrition and Metabolism ) and unpublished data ( mainly from industry ) . The exceptions were journal articles on herbal medicine , mostly indexed in Chinese language data bases . CONCLUSIONS A search of only the medline data base is insufficient for systematic review s of diabetes , because in about 34 % of review s the missed trials could affect the results of the meta- analysis . It is recommended that central ( on the Cochrane Library ) also be search ed . Scanning meeting abstract s , and seeking unpublished data are also recommended if the intervention has only recently been introduced
These outcomes advance the current underst and ing of Ca digestibility and utilisation , and should contribute towards establishing requirements for digestible Ca .
Consequently , pig diets will be more correctly formulated if digestible Ca values are used in estimating requirements for Ca
Ca digestibility and utilisation in growing pigs are not well understood , and are usually neglected in diet formulation .
This has implication s not only for the accurate determination of its requirements but also for its interactions with other nutrients .
A systematic review and meta- analysis ( meta-regression ) of published trials was carried out to quantify factors affecting Ca absorption and utilisation , and to derive an estimate of Ca endogenous excretion .