Changes in bone turnover markers after calcium-enriched milk supplementation in healthy postmenopausal women: a randomized, double-blind, prospective clinical trial.
OBJECTIVE
To assess the effect of calcium, phosphorus, lactose, and vitamin D fortified skimmed milk on biomarkers of bone turnover in healthy postmenopausal women.


METHODS
The design was of a prospective, double-blind, randomized, 6 months study. Eighty postmenopausal women (aged 49-71 y) were allocated in two groups receiving 750 mL/day of a fortified skimmed milk containing 1,200 mg of calcium and 5.7 microg of vitamin D (group A) or 900 mg of calcium and 5.7 microg of vitamin D (group B). Ultrasound bone mass measurements and biochemical markers of bone formation, serum bone-specific alkaline phosphatase (AP), and carboxi-terminal propeptide of type I procollagen (PICP) and of bone resorption, urinary excretion of pyridinoline (Pyr), deoxypyridinoline (D-Pyr), and urinary type I collagen cross-linked N-telopeptide (NTx) were performed at baseline and after 10 weeks and 6 months of follow-up.


RESULTS
PICP levels showed a significant reduction during the study, but no differences were observed between groups (-18.47 +/- 11.4 group A vs -14.42 +/- 12.5 group B). Pyr levels decreased in group A (P < 0.001), whereas no changes were detected in group B. At the end of the study, a significant difference (P < 0.01) was detected between groups in Pyr (-23.66 +/- 5.7 group Avs 3.465 +/- 7.1 group B) and D-Pyr (-16.64 +/- 1.6 group Avs 2.955 +/- 2.1 group B). At the 6th month, serum 25OH vitamin D increased in group A and decreased in group B (P = 0.007). Additionally, no differences were observed between groups in bone mass and in the other bone markers. Body weight was unchanged for group A, whereas a significant increase was observed in group B.


CONCLUSIONS
The daily intake of 750 mL of enriched skimmed milk containing 1,200 mg of calcium appears to be a useful, safe, and acceptable measure to calcium supplementation in healthy elderly postmenopausal women.
Palacios
Santiago
S
Institute Palacios of Woman's Health, Madrid, Spain.
Castelo-Branco
Camil
C
Cifuentes
Isabel
I
von Helde
Sueli
S
Baró
Luis
L
Tapia-Ruano
Concepción
C
Menéndez
Carmen
C
Rueda
Camilo
C
D000368:Aged; D000596:Amino Acids / Q000652:urine; D000818:Animals; D015415:Biomarkers / Q000032:analysis; D001835:Body Weight; D001862:Bone Resorption / Q000378:metabolism* / Q000517:prevention & control; D002118:Calcium / Q000008:administration & dosage*; D002762:Cholecalciferol / Q000008:administration & dosage*; D004311:Double-Blind Method; D005260:Female; D005527:Food, Fortified; D006801:Humans; D008875:Middle Aged; D008892:Milk / Q000737:chemistry*; D015663:Osteoporosis, Postmenopausal / Q000517:prevention & control; D010446:Peptide Fragments / Q000097:blood; D011347:Procollagen / Q000097:blood; D011446:Prospective Studies; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood
D000596:Amino Acids; D015415:Biomarkers; D010446:Peptide Fragments; D011347:Procollagen; C042813:procollagen type I carboxy terminal peptide; D014807:Vitamin D; D002762:Cholecalciferol; C015484:pyridinoline; C104450:25-hydroxyvitamin D; D002118:Calcium