Submitted to: Journal of Federation of American Societies for Experimental Biology
Publication Type: Abstract Only
Publication Acceptance Date: December 1, 2004
Publication Date: March 7, 2005
Citation: Hunt, C.D., Butte, N.F. 2005. Boron concentrations remain stable in milk from mothers of full-term exclusively breast-fed infants during the first four months of lactation [abstract]. The Federation of American Societies for Experimental Biology Journal. 19(5):A1704. Technical Abstract: To expand the finding from this laboratory that human milk boron (B) concentrations remain stable during the first 3 months of lactation, we analyzed archived milk collected (1980-84) from lactating mothers of full-term, exclusively breast-fed, infants living in Houston, TX. Samples were collected once a month for 4 months and analyzed for B, Ca, and Zn by inductively coupled plasma-mass spectrometry after digestion with HNO3 and H2O2 in Teflon tubes. A linear model (treating month as a continuous variable) indicated that B concentrations were stable between month 1 and 4 (0.042 ± 0.004 to 0.035± 0.003 ug/g milk, x ± SEM, p = 0.14). Ca concentrations decreased slightly over time (280 ± 7 to 269 ± 7 ug/g milk, p < 0.02) while Zn decreased substantially (2.6 ± 0.2 to 1.3 ± 0.1 ug/g milk, p < 0.0001). Mean Ca and Zn concentrations were not different from those measured earlier by atomic absorption (Am J Clin Nutr, 1987;45:42). The stable concentration of B in human milk over time is similar to that reported earlier by our laboratory (Am J Clin Nutr, In press) for samples collected in St. John's, Newfoundland, (wk 1: 0.030; wk 12: 0.028 ug/g, p = 0.5) and provides further evidence that B is homeostatically regulated. Because dietary boron is variable and highly bioavailable, future investigations of boron regulatory mechanisms should focus on metabolism of bone (major storage site of B) and kidney excretion (major excretory route for B).