Dual tracer stable isotopic assessment of calcium absorption and endogenous fecal excretion in low birth weight infants

Steven A. Abrams, Nora V. Esteban, Nancy E. Vieira, Alfred L. Yergey

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Using a dual tracer (44Ca orally and46Ca i.v.) stable isotope technique, true dietary Ca absorption, endogenous fecal Ca excretion, and net Ca retention were measured in 12 low birth weight (1426 ± 260 g) infants fed a high Ca-containing formula. Endogenous fecal Ca excretion averaged 7.2 ± 4.1% of intake, and exceeded 10% of intake in three infants. Net Ca retention, 103 ± 38 mg/kg/d, was consistent with previous studies of Ca retention obtained using mass balance techniques and correlated closely (r = 0.98, p < 0.001) with true Ca absorption but not with endogenous fecal excretion (r = — 0.40, p = 0.19). Although endogenous fecal excretion may represent a significant source of Ca loss for some low birth weight infants, these data suggest that net Ca retention in low birth weight infants fed a high Ca-containing formula is primarily determined by the total dietary Ca absorbed.

Original languageEnglish (US)
Pages (from-to)615-618
Number of pages4
JournalPediatric Research
Issue number6
StatePublished - Jun 1991


ASJC Scopus subject areas

  • Pediatrics, Perinatology, and Child Health

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