|Abrams, Steven -|
|Chen, Zhensheng -|
|Hawthorne, Keli -|
Submitted to: Journal of Bone and Mineral Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 17, 2013
Publication Date: January 2, 2014
Citation: Abrams, S.A., Chen, Z., Hawthorne, K.M. 2014. Magnesium metabolism in 4-year-old to 8-year-old children. Journal of Bone and Mineral Research. 29(1):118-122. Interpretive Summary: Magnesium is important in bone health, but few studies have evaluated magnesium intake or its absorption by the body and how these relate to bone mineral amount (content) and density in small children. We looked at this issue in children 4 to 8 years of age using carefully done diet records and stable isotopes to measure absorption. We found that magnesium intake and total magnesium absorption were significantly associated with both total body bone mineral content and density. Our results show that usual magnesium intakes in small children in the United States meet dietary requirements in most but not all children. Within the usual range of children's diets in the United States, dietary magnesium intake and absorption may be important, relatively unrecognized factors in bone health.
Technical Abstract: Magnesium (Mg) is a key factor in bone health, but few studies have evaluated Mg intake or absorption and their relationship with bone mineral content (BMC) or bone mineral density (BMD) in children. We measured Mg intake, absorption, and urinary excretion in a group of children 4 to 8 years of age. Mg absorption was determined using a dual-tracer stable isotope technique, with 25Mg given intravenously and 26Mg given orally. We found a small, but significantly greater Mg absorption efficiency (percentage absorption) in males than females (67% +/-12% versus 60% +/-8%, p=0.02) but no difference in estimated net Mg retention (average of 37 mg/d in both males and females). Relating dietary Mg intake to estimated Mg retention showed that an intake of 133 mg/d, slightly above the current estimated average requirement (EAR) of 110 mg/d, led to a net average retention of 10 mg/d, the likely minimum growth-related need for this age group. Covariate analysis showed that Mg intake and total Mg absorption, but not calcium intake or total absorption, were significantly associated with both total body BMC and BMD. These results suggest that usual Mg intakes in small children in the United States meet dietary requirements in most but not all children. Within the usual range of children's diets in the United States, dietary Mg intake and absorption may be important, relatively unrecognized factors in bone health.