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ARS Home » Northeast Area » Boston, Massachusetts » Jean Mayer Human Nutrition Research Center On Aging » Research » Publications at this Location » Publication #328272
Title: Osteocalcin carboxylation is not associated with body weight or percent fat changes during weight loss in post menopausal women

Author
item CENTI, AMANDA - Tufts University
item BOOTH, SARAH - Tufts University
item GUNDBERG, CAREN - Yale School Of Medicine
item SALTZMAN, EDWARD - Tufts University
item NICKLAS, BARBARA - Wake Forest University
item SHEA, KYLA - Tufts University

Submitted to: Endocrine Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/27/2015
Publication Date: 12/1/2015
Citation: Centi, A., Booth, S.L., Gundberg, C., Saltzman, E., Nicklas, B., Shea, K. 2015. Osteocalcin carboxylation is not associated with body weight or percent fat changes during weight loss in post menopausal women. Endocrine Journal. 50(3):627-632.

Interpretive Summary: Osteocalcin is a vitamin K dependent bone protein used as a marker of bone formation. Vitamin K is required for the carboxylation of osteocalcin, which is a biochemical transformation of the protein that confers its function in bone. Mouse models have demonstrated a role for the uncarboxylated form of osteocalcin in energy metabolism, but human data are equivocal. The purpose of this study was to determine the associations between changes in measures of different states of carboxylation of osteocalcin and changes in body weight and percent body fat in obese, but otherwise healthy post menopausal women undergoing a 20 week weight loss program. All participants received supplemental vitamins K and D and calcium. Body weight and body fat were assessed before and after the intervention. Serum measures of osteocalcin and a second measure of bone formation, procollagen type 1N-terminal propeptide, were measured. Women lost an average of 10.9 kg and 4% body fat. Serum concentrations of osteocalcin and procollagen type 1N-terminal propeptide did not change over the twenty week intervention, nor were these measures associated with changes in weight or % body fat. Our data do not support an association between any serum measures of osteocalcin and weight or % body fat loss in post-menopausal women supplemented with nutrients implicated in bone health.

Technical Abstract: Osteocalcin (OC) is a vitamin K dependent bone protein used as a marker of bone formation. Mouse models have demonstrated a role for the uncarboxylated form of OC (ucOC) in energy metabolism, including energy expenditure and adiposity, but human data are equivocal. To determine the associations between changes in measures of OC and changes in body weight and percent body fat in obese, but otherwise healthy post menopausal women undergoing a 20 week weight loss program. All participants received supplemental vitamins K and D and calcium. Body weight and body fat percentage (%BF) were assessed before and after the intervention. Serum OC [(total (tOC), ucOC, percent uncarboxylated (%ucOC)], and procollagen type 1N-terminal propeptide (P1NP; a measure of bone formation) were measured. Women lost an average of 10.9 +/- 3.9 kg and 4 %BF. Serum concentrations of tOC, ucOC, %ucOC, and P1NP did not significantly change over the twenty week intervention, nor were these measures associated with changes in weight (all p > 0.27) or %BF (all p > 0.54). Our data do not support an association between any serum measure of OC and weight or %BF loss in post-menopausal women supplemented with nutrients implicated in bone health.