Effect of phylloquinone supplementation on glucose homeostasis in humans

Background Under gamma carboxylated osteocalcin (ucOC) increases insulin secretion and decreases glucose concentrations in mice Objective We determined whether changes in ucOC concentrations in humans were associated with changes in insulin and glucose concentrations Design Twenty one community dwelling postmenopausal women received I mg phylloquinone daily for 12 mo (experimental group) and 21 subjects were treated with a placebo during the same period (control group) Total serum osteocalcin ucOC glucose and insulin concentrations were measured before and 6 and 12 mo after treatment The homeostasis model assessment of insulin resistance (HOMA ER) was calculated and correlated with ucOC concentrations Results Before administration of the placebo or phylloquinone total osteocalcin ucOC glucose and insulin concentrations and HOMA ER (1 24 0 15 for the control group compared with 1 93 +/- 0 37 for the experimental group) did not differ After treatment total osteocalcin concentrations were similar at 6 and 12 mo At 6 mo serum ucOC concentrations in the experimental group were 0 96 008 ng/mL compared with 2 94 0 27 ng/mL in the control group (P < 0 001) At 12 mo serum ucOC concentrations were 0 92 0 09 ng/mL and 3 13 0 26 ng/mL (P < 0 001) in experimental and control groups respectively Despite a decrease of approximate to 200% in ucOC concentrations HOMA IR was similar in the 2 groups at 6 and 12 mo (at 6 mo HOMA ER was 2 24 0 54 and 1 52 +/- 0 23 in the experimental and control groups respectively at 12 mo HOMA ER was 2 13 038 and 1 47 022 in the ex experimental and control groups respectively P = NS) Conclusions In postmenopausal women phylloquinone administration is not associated with changes in insulin secretion and action despite reductions in ucOC concentrations Changes in ucOC con centrations do not alter glucose metabolism in women This trial was registered at clinicaltrials gov as NCT00062595 Am J Clin Nutr 2010 92 1528-32