Conclusions Vitamin D supplementation did not improve EF .
The significant effect of vitamin D in diabetics and a tendency for an association with BMI may indicate a role of excess adiposity and insulin resistance in modulating the effects of vitamin D on vascular function .
Abstract Background In addition to regulating calcium homoeostasis and bone health , vitamin D influences vascular and metabolic processes including endothelial function ( EF ) and insulin signalling .
Vitamin D3 supplementation for 16 weeks improves flow-mediated dilation in overweight African-American adults.
BACKGROUND A growing body of evidence has linked vitamin D deficiency to increased risk of cardiovascular disease . Vitamin D deficiency is also more common in African Americans for whom an increased cardiovascular disease risk exists . This study sought to test the hypothesis that 16 weeks of 60,000 IU monthly supplementation of oral vitamin D(3 ) would improve flow-mediated dilation ( FMD ) in African Americans , whereas no change would be observed in the placebo group . METHODS A r and omized , double-blind , placebo-controlled clinical trial was conducted . Fifty-seven African-American adults were r and omly assigned to either the placebo group or vitamin D group . RESULTS Following 16 weeks of placebo ( n = 23 ; mean age 31 ± 2 years ) or 60,000 IU monthly oral vitamin D(3 ) ( n = 22 ; mean age 29 ± 2 years ) , serum concentrations of 25-hydroxyvitamin D ( 25(OH)D ) increased from 38.2 ± 3.0 to 48.7 ± 3.2 nmol/l and 34.3 ± 2.2 to 100.9 ± 6.6 nmol/l , respectively . No changes in serum parathyroid hormone ( PTH ) , serum calcium , or urine calcium/creatinine were observed following either treatment . Following 16 weeks of treatment , significant improvements in FMD were only observed in the vitamin D group ( 1.8 ± 1.3 % ) , whereas the placebo group had no change ( -1.3 ± 0.6 % ) . Similarly , the vitamin D group exhibited an increase in absolute change in diameter ( 0.005 ± 0.004 cm ) and FMD/shear ( 0.08 ± 0.04 % /s(-1 ) , area under the curve ( AUC ) × 10(3 ) ) following treatment , whereas no change ( -0.005 ± 0.002 cm and -0.02 ± 0.02 % /s(-1 ) , AUC , respectively ) was observed following placebo . CONCLUSION Supplementation of 60,000 IU monthly oral vitamin D(3 ) ( ~2,000 IU/day ) for 16 weeks is effective at improving vascular endothelial function in African-American adults
Conclusions Vitamin D supplementation did not improve EF .
The significant effect of vitamin D in diabetics and a tendency for an association with BMI may indicate a role of excess adiposity and insulin resistance in modulating the effects of vitamin D on vascular function .
Abstract Background In addition to regulating calcium homoeostasis and bone health , vitamin D influences vascular and metabolic processes including endothelial function ( EF ) and insulin signalling .