Overall , intervention groups obtained higher 25(OH)D concentration than controls and there was obvious dose – response effect between intake dose and 25(OH)D concentration .
Baseline 25(OH)D concentration and age were significant indicators for 25(OH)D concentration .
Conclusions Regional- and age-specific recommended dosages of VitD supplements for population to achieve optimal 25(OH)D concentrations have been suggested
Background / Objectives Optimal doses of vitamin D ( VitD ) supplement in different population s are unclear .
We aim to evaluate the relationship between VitD supplementation and post-intervention serum 25-hydroxyvitamin D [ 25(OH)D ] concentration , to provide a recommended dosage of VitD for achieving an optimal 25(OH)D concentration for different population s .
Cholecalciferol supplementation throughout winter does not affect markers of bone turnover in healthy young and elderly adults.
Although there have been several studies of the effect of vitamin D status on bone turnover in the elderly , the findings are unclear , and , furthermore , to date very few have investigated this in young adults . The objective of these r and omized , placebo-controlled , double-blind , 2-center intervention studies was to investigate the effect of cholecalciferol supplementation ( 0 , 5 , 10 , and 15 microg cholecalciferol/d ) throughout winter time on indices of vitamin D status and bone turnover in young ( aged 20 - 40 y ; n = 215 ) and elderly ( aged > or = 64 y ; n = 204 ) adults , with relatively high mean calcium intakes of 976 and 874 mg/d , respectively .  Fasting serum concentrations of 25-hydroxyvitamin D [ 25(OH)D ] , parathyroid hormone ( PTH ) , osteocalcin , bone-specific alkaline phosphatase , and carboxyterminal collagen crosslinks were measured by enzyme immunoassays at baseline and endpoint . Fok I and Taq I vitamin D receptor ( VDR ) genotypes were determined by real-time PCR . Endpoint serum 25(OH)D increased ( P < 0.0001 ) in a dose-related manner with increasing supplemental cholecalciferol ( up to 15 microg/d ) in 20 - 40-y olds and up to 10 microg/d in > or = 64-y olds . Endpoint serum PTH was lower ( P < 0.05 ) in the 3 cholecalciferol-supplemented groups compared with that in the placebo group in > or = 64-y olds , but cholecalciferol supplementation did not affect other markers in either cohort and there was no significant interaction with VDR genotype . In conclusion , cholecalciferol supplementation alone throughout winter did not affect bone turnover markers in apparently healthy young and elderly adults , even when stratified by VDR genotype
Overall , intervention groups obtained higher 25(OH)D concentration than controls and there was obvious dose – response effect between intake dose and 25(OH)D concentration .
Baseline 25(OH)D concentration and age were significant indicators for 25(OH)D concentration .
Conclusions Regional- and age-specific recommended dosages of VitD supplements for population to achieve optimal 25(OH)D concentrations have been suggested
Background / Objectives Optimal doses of vitamin D ( VitD ) supplement in different population s are unclear .
We aim to evaluate the relationship between VitD supplementation and post-intervention serum 25-hydroxyvitamin D [ 25(OH)D ] concentration , to provide a recommended dosage of VitD for achieving an optimal 25(OH)D concentration for different population s .