title: Differences in calcium metabolism between adolescent and adult females.
abstract: A 3-wk metabolic study measured calcium balance in 14 white adolescent girls and 11 young adult women. Subjects were housed in a sorority to simulate a free-living environment. A 6-d menu cycle consisted of foods typically eaten by teenagers and averaged 1332 mg Ca/d. Adolescents had a significantly higher calcium balance of 326 +/- 107 mg/d (mean +/- SD) than adults, who averaged 73 +/- 104 mg/d (P < 0.001). No adult > age 21 y was in positive calcium balance. Adolescents had lower urinary calcium excretion values (P < 0.001), lower fecal calcium excretion (P < 0.01), and greater net absorption (P < 0.001) than adults. Calcium balance was negatively correlated with years postmenarche (r = -0.788, P = 0.0001) and height (r = -0.650, P = 0.001). Net calcium absorption was positively correlated with parathyroid hormone concentrations (r = 0.537, P = < 0.01). Thus, the growth demands of adolescents are met by more efficient net absorption and retention of calcium compared with young adults.
authors.affiliation: Department of Foods and Nutrition, Purdue University, West Lafayette, IN 47907-1264.
authors.forename: C M
authors.initials: CM
authors.lastname: Weaver
authors.forename: B R
authors.initials: BR
authors.lastname: Martin
authors.forename: K L
authors.initials: KL
authors.lastname: Plawecki
authors.forename: M
authors.initials: M
authors.lastname: Peacock
authors.forename: O B
authors.initials: OB
authors.lastname: Wood
authors.forename: D L
authors.initials: DL
authors.lastname: Smith
authors.forename: M E
authors.initials: ME
authors.lastname: Wastney
mesh_terms: D000293:Adolescent; D000328:Adult; D000375:Aging / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D002648:Child; D004032:Diet; D005260:Female; D006801:Humans; D009584:Nitrogen / Q000378:metabolism; D009751:Nutritional Requirements
chemical_list: D009584:Nitrogen; D002118:Calcium