Increased vitamin D intake differentiated according to skin color is needed to meet requirements in young Swedish children during winter: a double-blind randomized clinical trial.

Background: Dark skin and low exposure to sunlight increase the risk of vitamin D insufficiency in children.Objective: The aim of the study was to evaluate the amount of vitamin D needed to ascertain that most children >4 y of age attain sufficient serum 25-hydroxyvitamin D [S-25(OH)D; i.e., ≥50 nmol/L] during winter regardless of latitude and skin color.Design: In a longitudinal, double-blind, randomized, food-based intervention study, 5- to 7-y-old children from northern (63°N) and southern (55°N) Sweden with fair (n = 108) and dark (n = 98) skin were included. Children, stratified by skin color by using Fitzpatrick's definition, were randomly assigned to receive milk-based vitamin D3 supplements that provided 2 (placebo), 10, or 25 μg/d during 3 winter months.Results: Mean daily vitamin D intake increased from 6 to 17 μg and 26 μg in the intervention groups supplemented with 10 and 25 μg, respectively. In the intention-to-treat analysis, 90.2% (95% CI: 81.1%, 99.3%) of fair-skinned children randomly assigned to supplementation of 10 μg/d attained sufficient concentrations, whereas 25 μg/d was needed in dark-skinned children to reach sufficiency in 95.1% (95% CI: 88.5%, 100%). In children adherent to the study product, 97% (95% CI: 91.3%, 100%) and 87.9% (95% CI: 76.8%, 99%) of fair- and dark-skinned children, respectively, achieved sufficient concentrations if supplemented with 10 μg/d. By using 95% prediction intervals for 30 and 50 nmol S-25(OH)D/L, intakes of 6 and 20 μg/d are required in fair-skinned children, whereas 14 and 28 μg/d are required in children with dark skin.Conclusion: Children with fair and dark skin require vitamin D intakes of 20 and 28 μg/d, respectively, to maintain S-25(OH)D ≥50 nmol/L, whereas intakes of 6 and 14 μg/d, respectively, are required to maintain concentrations ≥30 nmol/L during winter. This trial was registered at clinicaltrials.gov as NCT01741324.

Öhlund I ，Lind T ，Hernell O ，Silfverdal SA ，Karlsland Åkeson P ... -  《-》

Serum Vitamin D Depends Less on Latitude Than on Skin Color and Dietary Intake During Early Winter in Northern Europe.

Åkeson PK ，Lind T ，Hernell O ，Silfverdal SA ，Öhlund I ... -  《-》

Daily supplementation with 15 μg vitamin D(2) compared with vitamin D(3) to increase wintertime 25-hydroxyvitamin D status in healthy South Asian and white European women: a 12-wk randomized, placebo-controlled food-fortification trial.

Background: There are conflicting views in the literature as to whether vitamin D2 and vitamin D3 are equally effective in increasing and maintaining serum concentrations of 25-hydroxyvitamin D [25(OH)D], particularly at lower doses of vitamin D.Objective: We aimed to investigate whether vitamin D2 or vitamin D3 fortified in juice or food, at a relatively low dose of 15 μg/d, was effective in increasing serum total 25(OH)D and to compare their respective efficacy in South Asian and white European women over the winter months within the setting of a large randomized controlled trial.Design: A randomized, double-blind, placebo-controlled food-fortification trial was conducted in healthy South Asian and white European women aged 20-64 y (n = 335; Surrey, United Kingdom) who consumed placebo, juice supplemented with 15 μg vitamin D2, biscuit supplemented with 15 μg vitamin D2, juice supplemented with 15 μg vitamin D3, or biscuit supplemented with 15 μg vitamin D3 daily for 12 wk. Serum 25(OH)D was measured by liquid chromatography-tandem mass spectrometry at baseline and at weeks 6 and 12 of the study.Results: Postintervention in the 2 ethnic groups combined, both the vitamin D3 biscuit and the vitamin D3 juice groups showed a significantly greater absolute incremental change (Δ) in total 25(OH)D when compared with the vitamin D2 biscuit group [Δ (95% CI): 15.3 nmol/L (7.4, 23.3 nmol/L) (P < 0.0003) and 16.0 nmol/L (8.0, 23.9 nmol/L) ( P < 0.0001)], the vitamin D2 juice group [Δ (95% CI): 16.3 nmol/L (8.4, 24.2 nmol/L) (P < 0.0001) and 16.9 nmol/L (9.0, 24.8 nmol/L) (P < 0.0001)], and the placebo group [Δ (95% CI): 42.3 nmol/L (34.4, 50.2 nmol/L) (P < 0.0001) and 42.9 nmol/L (35.0, 50.8 nmol/L) (P < 0.0002)].Conclusions: With the use of a daily dose of vitamin D relevant to public health recommendations (15 μg) and in vehicles relevant to food-fortification strategies, vitamin D3 was more effective than vitamin D2 in increasing serum 25(OH)D in the wintertime. Vitamin D3 may therefore be a preferential form to optimize vitamin D status within the general population. This trial was registered at www.controlled-trials.com as ISRCTN23421591.

Tripkovic L ，Wilson LR ，Hart K ，Johnsen S ，de Lusignan S ，Smith CP ，Bucca G ，Penson S ，Chope G ，Elliott R ，Hyppönen E ，Berry JL ，Lanham-New SA ... -  《-》

Vitamin D Intervention and Bone: A Randomized Clinical Trial in Fair- and Dark-skinned Children at Northern Latitudes.

Karlsland Åkeson P ，Åkesson KE ，Lind T ，Hernell O ，Silfverdal SA ，Öhlund I ... -  《-》

Serum 25-hydroxyvitamin D levels in preschool-age children in northern Sweden are inadequate after summer and diminish further during winter.

Öhlund I ，Silfverdal SA ，Hernell O ，Lind T ... -  《-》