Baseline serum VD possibly influences the effect of VD repletion on inflammatory markers .
Risk of bias was present in most studies , thus supporting the need for higher quality studies in this area to more conclusively underst and the role VD supplementation has on inflammatory pathways
BACKGROUND Obesity induced low- grade chronic inflammation disrupts proper immune and metabolic function .
Vitamin D deficiency increases inflammation , which is associated with cardiometabolic risk .
This systematic review examines the association between oral vitamin D ( VD ) supplementation and circulating inflammatory biomarkers and glycemic outcomes from r and omized controlled trials ( RCTs ) of overweight and /or obese adults .
High-Dose Vitamin D Supplementation in People With Prediabetes and Hypovitaminosis D
OBJECTIVE Low vitamin D levels predict the development of diabetes . This double-blind , r and omized , control study in subjects with prediabetes and hypovitaminosis D evaluated whether high doses of vitamin D for 1 year affected insulin secretion , insulin sensitivity , and the development of diabetes . RESEARCH DESIGN AND METHODS A total of 1,551 subjects ≥40 years of age not known to have diabetes were screened with A1C levels . Subjects with A1C levels of 5.8–6.9 % underwent an oral glucose tolerance test ( OGTT ) . Subjects with prediabetes and 25-OH vitamin D ( 25-OHD ) levels < 30 ng/mL were r and omized to receive weekly placebo ( n = 53 ) or vitamin D ( n = 56 ) with doses based on body weight and baseline 25-OHD levels . OGTTs were performed 3 , 6 , 9 , and 12 months later . Insulin secretion and sensitivity were measured , and the proportion of subjects developing diabetes was assessed . RESULTS 25-OHD levels rapidly rose from 22 to nearly 70 ng/mL after vitamin D supplementation with a mean weekly dose of 88,865 IU . There were no differences between the placebo and vitamin D groups regarding fasting plasma glucose , 2-h glucose , or insulin secretion and sensitivity or in the percent developing diabetes or returning to normal glucose tolerance . No subjects experienced increased serum or urinary calcium levels . At 12 months , A1C levels were significantly slightly less ( 0.2 % ) in the vitamin D group . CONCLUSIONS In individuals with prediabetes and hypovitaminosis D , doses of vitamin D supplementation design ed to raise serum 25-OHD levels into the upper-normal range for 1 year had no effect on insulin secretion , insulin sensitivity , or the development of diabetes  compared with placebo administration
Baseline serum VD possibly influences the effect of VD repletion on inflammatory markers .
Risk of bias was present in most studies , thus supporting the need for higher quality studies in this area to more conclusively underst and the role VD supplementation has on inflammatory pathways
BACKGROUND Obesity induced low- grade chronic inflammation disrupts proper immune and metabolic function .
Vitamin D deficiency increases inflammation , which is associated with cardiometabolic risk .
This systematic review examines the association between oral vitamin D ( VD ) supplementation and circulating inflammatory biomarkers and glycemic outcomes from r and omized controlled trials ( RCTs ) of overweight and /or obese adults .