title: Calcium fortification systems differ in bioavailability.
abstract: The objective of this study was to compare the bioavailability of calcium from two fortification systems used in orange juice. The design was randomized crossover, within-subject. The subjects were 25 healthy premenopausal women in an academic health sciences center. Two commercially marketed calcium-fortified orange juices, ingested in an amount providing 500 mg calcium, were taken at breakfast after an overnight fast. The two fortification systems tested were calcium citrate malate and a combination of tricalcium phosphate and calcium lactate (tricalcium phosphate/calcium lactate). The main outcome measure was the area under the curve (AUC) for the increase in serum calcium from 0 to 9 hours after ingesting the test calcium source. Statistical analyses performed were repeated measures analysis of variance, testing source, and sequence. AUC 9 was 48% greater for calcium citrate malate than for tricalcium phosphate/calcium lactate ( P < .001); absorbed calcium calculated from AUC 9 values (mean+/-standard error of the mean) was 148+/-9.0 mg and 100+/-8.9 mg for calcium citrate malate and tricalcium phosphate/calcium lactate, respectively. The results indicate that equivalent calcium contents on a nutritional label do not guarantee equivalent nutritional value. Nutritionists and dietetics professionals should encourage manufacturers of fortified products to provide information on bioavailability.
authors.affiliation: Creighton University Medical Center, 601 N. 30th Street, Omaha, NE 68131, USA. rheaney@creighton.edu
authors.forename: Robert P
authors.initials: RP
authors.lastname: Heaney
authors.forename: Karen
authors.initials: K
authors.lastname: Rafferty
authors.forename: M Susan
authors.initials: MS
authors.lastname: Dowell
authors.forename: June
authors.initials: J
authors.lastname: Bierman
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D019540:Area Under Curve; D001628:Beverages; D001682:Biological Availability; D002118:Calcium / Q000097:blood*; D017610:Calcium Compounds / Q000493:pharmacokinetics; D002130:Calcium Phosphates / Q000493:pharmacokinetics; D002136:Calcium, Dietary / Q000493:pharmacokinetics*; D002957:Citrus / Q000737:chemistry*; D018592:Cross-Over Studies; D005260:Female; D005527:Food, Fortified; D006801:Humans; D007773:Lactates / Q000493:pharmacokinetics; D008875:Middle Aged; D009753:Nutritive Value
chemical_list: D017610:Calcium Compounds; D002130:Calcium Phosphates; D002136:Calcium, Dietary; D007773:Lactates; C110051:calcium lactate; D002118:Calcium