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 .
Serum concentrations of 1,25-dihydroxyvitamin D2 and 1,25-dihydroxyvitamin D3 in response to vitamin D2 and vitamin D3 supplementation.
OBJECTIVE The purpose of this study was to determine 1,25-dihydroxyvitamin D3 [ 1,25(OH)2D3 ] and 1,25-dihydroxyvitamin D2 [ 1,25(OH)2D2 ] levels in healthy adults consuming 1000 IU vitamin D2 or vitamin D3 per day for 11 weeks . SUBJECTS AND DESIGN Blood from 34 healthy male and female adults , aged 18 to 79 years , from a placebo-controlled , double-blind study who received a placebo , 1000 IU vitamin D3 , or 1000 IU vitamin D2 daily for 11 weeks at end of winter was analyzed . Serum levels of 25-hydroxyvitamin D2 , 25-hydroxyvitamin D3 , 1,25(OH)2D2 , and 1,25(OH)2D3  were determined by liquid chromatography-t and em mass spectroscopy . RESULTS Of the adults , 82 % were vitamin D insufficient ( serum 25-hydroxyvitamin D [ 25(OH)D < 30 ng/mL ] ) at the start of the study . Administration of vitamin D2 and vitamin D3 induced similar increases in total 25(OH)D as well as in 25-hydroxyvitamin D2 and 25-hydroxyvitamin D3 , respectively . Compared with placebo and adjusting for baseline levels , 1000 IU daily of vitamin D2 was associated with a mean increase of 7.4 pg/mL ( 95 % confidence interval , 4.4 - 10.3 ) in 1,25(OH)2D2 , which was accompanied by a mean decrease of 9.9 pg/mL ( -15.8 to -4.0 ) in 1,25(OH)2D3 . No such differences accompanied administration of 1000 IU daily of vitamin D3 . CONCLUSION Vitamin D2 and vitamin D3 were effective in raising and maintaining total serum concentrations of 25(OH)D. Ingestion of vitamin D2 also result ed in an increase in serum concentrations of 1,25(OH)2D2 . This increase was accompanied by a comparable decrease in serum concentrations of 1,25(OH)2D3 ; therefore , the total 1,25-dihydroxyvitamin D [ 1,25(OH)2D ] concentrations did not significantly change after 11 weeks compared with baseline levels . Ingestion of vitamin D3 did not alter serum concentrations of 1,25(OH)2D3 or total 1,25(OH)2D . Therefore , ingestion of 1000 IU vitamin D2 or vitamin D3 for 11 weeks was effective in raising total serum concentrations of 25(OH)D as well as sustaining serum concentrations of total 1,25(OH)2D
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 .