Submitted to: Journal of Nutrition
Publication Type: Peer reviewed journal
Publication Acceptance Date: 7/26/2005
Publication Date: N/A
Citation: Interpretive Summary: Boron is a trace element that may be beneficial to humans for bone health, glucose metabolism, and immune function. The aim of the present work was to measure boron concentrations in human milk during the first 4 mo of lactation. The concentration of boron and other minerals was determined in human milk once a month for 4 months using a sophisticated method called inductively coupled argon plasma optical emission spectroscopy. The levels of boron in human milk were constant during the first 4 months of lactation. The concentrations of magnesium increased slightly over time, while the concentrations of calcium and zinc decreased. This study provides evidence that boron in human milk may be metabolically regulated. Future investigations will focus on boron regulatory mechanisms involving bone and kidney metabolism.
Technical Abstract: Because boron is a bioactive element that satisfies several of the criteria for essentiality in humans, the aim of the present work was to determine the profile of boron metabolism in human milk during the first 4 mo of lactation. The concentration of boron and other minerals was determined in archived milk collected (1980-84) once a month for 4 months from lactating mothers of full-term, exclusively breast-fed, infants living in Houston, TX. A linear model (treating month as a continuous variable) indicated that B concentrations were stable (p = 0.14) between month 1 (3.88 ± 0.6 umol [42 ± 6.5 ug]/L milk) and 4 (3.24 ± 0.6 umol [35 ± 6.5 ug]/L milk, x ± SEM). Mg concentrations increased slightly over time (1.18 ± 0.09 to 1.36 ± 0.09 mmol/L, p < 0.0001) while Ca concentrations decreased slightly (7.01 ± 0.29 to 6.68 ± 0.29 mmol/L milk, p < 0.02) and Zn decreased substantially (0.04 ± 0.004 to 0.02 ± 0.004 mmol/L milk, p < 0.0001). Similarities in findings reported here and earlier (from samples collected in St. John’s, Newfoundland) provide further evidence that boron may be metabolically regulated. Future investigations of boron regulatory mechanisms should focus on metabolism of bone as the major storage site of B and kidney excretion, the major excretory route for B.