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Does calcium supplementation during the suckling period affect bone mineral density and bone zinc later in adult life?

This investigation aimed at evaluating long-term effects of dietary calcium supplementation during suckling period on calcium (Ca), magnesium (Mg), and zinc (Zn) in bone. Female Wistar rats were divided in four groups (12 to 15 animals in each): 1) supplemented with 6% suspension of Ca hydrogen phosphate in cow's milk during the suckling period (Ca-supplemented) and then fed on rodent feed with 1% Ca till the age of 3 months ; 2) Ca-supplemented and then fed on 0.45% Ca ; 3) sham-supplemented with cow’ s milk as suckling (sham-supplemented) and then fed on 1% Ca ; 4) sham-supplemented and then fed on 0.45% Ca. At the age of 3 months (young adult rats) whole body bone mineral density (BMD) was measured by dual energy X-ray absorptiometry, and Ca, Zn and Mg concentrations were analysed in femoral bone tissue by atomic absorption spectrometry. The experiment was conducted in accordance with the NIH Guidelines for the care and use of animals, and approved by authorized national institutions and Institute's Ethical Committee. Two-way analysis of variance evaluated the effects of Ca supplementation during the suckling period and the effects of two levels of Ca intake (1% or 0.45%) during the weaning and after weaning on BMD and bone Ca, Mg, and Zn. The results showed that Ca supplementation during the suckling period did not affect whole body BMD and bone Mg concentration in young adult rats, Ca concentration in the femur decreased 6.6%, and bone Zn concentration increased 5%. Animals fed on 1% Ca in feed had a slightly higher whole body BMD (2%), higher Ca concentration in the femur (9%), and lower bone Zn concentration (7%) than rats fed on 0.45% Ca. Bone Mg was unaffected. To conclude, under these experimental conditions Ca supplementation during the suckling period has no beneficial effect on bone mineral density in the adulthood. Effects on bone Zn deserve further exploration.

bone; bone mineral density; dietary calcium supplementation; magnesium; suckling rats; zinc

DOI : 10.1007/s10565-007-9052-8 ; SpringerLink Date: Wednesday, January 16, 2008