Available high- quality RCTs did not support a beneficial effect of cholecalciferol on systemic IL-6 and CRP .
Vitamin D supplementation reduces insulin resistance in South Asian women living in New Zealand who are insulin resistant and vitamin D deficient - a randomised, placebo-controlled trial.
Low serum 25-hydroxyvitamin D ( 25(OH)D ) has been shown to correlate with increased risk of type 2 diabetes . Small , observational studies suggest an action for vitamin D in improving insulin sensitivity and /or insulin secretion . The objective of the present study was to investigate the effect of improved vitamin D status on insulin resistance ( IR ) , utilising r and omised , controlled , double-blind intervention administering 100 microg ( 4000 IU ) vitamin D(3 ) ( n 42 ) or placebo ( n 39 ) daily for 6 months to South Asian women , aged 23 - 68 years , living in Auckl and , New Zeal and . Subjects were insulin resistant - homeostasis model assessment 1 (HOMA1)>1.93 and had serum 25(OH)D concentration < 50 nmol/l . Exclusion criteria included diabetes medication and vitamin D supplementation > 25 microg ( 1000 IU)/d . The HOMA2 computer model was used to calculate outcomes . Median ( 25th , 75th percentiles ) serum 25(OH)D(3 ) increased significantly from 21 ( 11 , 40 ) to 75 ( 55 , 84 ) nmol/l with supplementation . Significant improvements were seen in insulin sensitivity and IR ( P = 0.003 and 0.02 , respectively ) , and fasting insulin decreased ( P = 0.02 ) with supplementation compared with placebo . There was no change in C-peptide with supplementation . IR was most improved when endpoint serum 25(OH)D reached > or = 80 nmol/l . Secondary outcome variables ( lipid profile and high sensitivity C-reactive protein ) were not affected by supplementation . In conclusion , improving vitamin D status in insulin resistant women result ed in improved IR and sensitivity , but no change in insulin secretion . Optimal vitamin D concentrations for reducing IR were shown to be 80 - 119 nmol/l , providing further evidence for an increase in the recommended adequate levels . Registered Trial No. ACTRN12607000642482
Available high- quality RCTs did not support a beneficial effect of cholecalciferol on systemic IL-6 and CRP .