CONCLUSIONS Supplementation with vitamin D showed no effect on adiposity measures in adults
CONTEXT The independent or interactive effects of vitamin D and calcium on adiposity remain inconclusive .
OBJECTIVE The objective of this systematic review and meta- analysis was to assess whether vitamin D and calcium supplements cause changes in adiposity .
Role of Vitamin D in Insulin Secretion and Insulin Sensitivity for Glucose Homeostasis
Vitamin D functions are not limited to skeletal health benefits and may extend to preservation of insulin secretion and insulin sensitivity . This review summarizes the literature related to potential vitamin D influences on glucose homeostasis and insulin sensitivity . Cross-sectional data provide some evidence that circulating 25-hydroxyvitamin D ( 25(OH)D ) is inversely associated with insulin resistance , although direct measurements of insulin sensitivity are required for confirmation . Reported associations with insulin secretion , however , are contradictory . Available prospect i ve studies support a protective influence of high 25(OH)D concentrations on type 2 diabetes mellitus risk . There is a general lack of consistency in vitamin D intervention outcomes on insulin secretion and sensitivity , likely due to differences in subject population s , length of interventions , and forms of vitamin D supplementation . Vitamin D receptor gene polymorphisms and vitamin D interactions with the insulin like growth factor system may further influence glucose homeostasis . The ambiguity of optimal vitamin D dosing regimens and optimal therapeutic concentrations of serum 25(OH)D limit available intervention studies . Future studies , including cross-sectional and prospect i ve , should be performed in population s at high risk for both vitamin D deficiency and type 2 diabetes mellitus . Well- design ed , placebo-controlled , r and omized intervention studies are required to establish a true protective influence of  vitamin D on glucose homeostasis
CONCLUSIONS Supplementation with vitamin D showed no effect on adiposity measures in adults
CONTEXT The independent or interactive effects of vitamin D and calcium on adiposity remain inconclusive .
OBJECTIVE The objective of this systematic review and meta- analysis was to assess whether vitamin D and calcium supplements cause changes in adiposity .