Total calcium absorption is similar from infant formulas with and without prebiotics and exceeds that in human milk-fed infants

A dual tracer stable isotope method was used to assess calcium absorption in infants exclusively fed CF (n？=？30), PF (n？=？25) or HM (n？=？19). Analysis of variance was used to analyze calcium intake, fractional calcium absorption, and the amount of calcium absorbed.Calcium intake (Mean ± SEM) for PF was 534？±？17？mg/d and 557？±？16？mg/d for CF (p？=？0.33). Fractional calcium absorption was 56.8？±？2.6？% for PF and 59.2？±？2.3？% for CF (p？=？0.49). Total calcium absorbed for PF was 300？±？14？mg/d and 328？±？13？mg/d for CF (p？=？0.16). For HM infants calcium intake was 246？±？20？mg/d, fractional calcium absorption was 76.0？±？2.9？% and total calcium absorbed was 187？±？16？mg/d (p <0.001, compared to either PF or CF).Despite lower fractional calcium absorption of CF and PF compared to HM, higher calcium content in both led to higher total calcium absorption compared to HM infants. No significant effect of prebiotics was observed on calcium absorption or other markers of bone mineral metabolism.The standard for nutrient intake and bioavailability in the first months of life is the exclusively human milk-fed infant. Because of the possibility of lower bioavailability, the quantity of minerals important for bone development, including calcium, in infant formulas are greater than those found in human milk (HM). Concentration ranges for calcium in infant formulas are set by statute in the United States and many countries. Because of these higher nutrient concentrations, it is not possible to directly compare the intrinsic bioavailability of calcium from infant formulas to that of HM. Nonetheless, it is important to assure that the total amount of calcium absorbed from any infant formula is at least equal to that provided by HM and to evaluate calcium absorption as changes are made to infant formula composition.Prebiotics are currently routinely added to infant formulas. A prebiotic is a non-digestible food ingredient that brings about specific changes in the composition and/or activity