RESUMO
BACKGROUND: Little is known about how the genetic variation in vitamin D modulating genes influences ultraviolet (UV)B-induced 25-hydroxyvitamin D [25(OH)D] concentrations. In the Food with vitamin D (VitmaD) study, we showed that common genetic variants rs10741657 and rs10766197 in 25-hydroxylase (CYP2R1) and rs842999 and rs4588 in vitamin D binding protein (GC) predict 25(OH)D concentrations at late summer and after 6-mo consumption of cholecalciferol (vitamin D3)-fortified bread and milk. OBJECTIVES: In the current study, called the Vitamin D in genes (VitDgen) study, we analyzed associations between the increase in 25(OH)D concentrations after a given dose of artificial UVB irradiation and 25 single nucleotide polymorphisms located in or near genes involved in vitamin D synthesis, transport, activation, or degradation as previously described for the VitmaD study. Second, we aimed to determine whether the genetic variations in CYP2R1 and GC have similar effects on 25(OH)D concentrations after artificial UVB irradiation and supplementation by vitamin D3-fortified bread and milk. DESIGN: The VitDgen study includes 92 healthy Danes who received 4 whole-body UVB treatments with a total dose of 6 or 7.5 standard erythema doses during a 10-d period in winter. The VitmaD study included 201 healthy Danish families who were given vitamin D3-fortified bread and milk or placebo for 6 mo during the winter. RESULTS: After UVB treatments, rs10741657 in CYP2R1 and rs4588 in GC predicted UVB-induced 25(OH)D concentrations as previously shown in the VitmaD study. Compared with noncarriers, carriers of 4 risk alleles of rs10741657 and rs4588 had lowest concentrations and smallest increases in 25(OH)D concentrations after 4 UVB treatments and largest decreases in 25(OH)D concentrations after 6-mo consumption of vitamin D3-fortified bread and milk. CONCLUSION: Common genetic variants in the CYP2R1 and GC genes modify 25(OH)D concentrations in the same manner after artificial UVB-induced vitamin D and consumption of vitamin D3-fortified bread and milk.
Assuntos
Colecalciferol/uso terapêutico , Colestanotriol 26-Mono-Oxigenase/genética , Alimentos Fortificados , Polimorfismo de Nucleotídeo Único , Pele/efeitos da radiação , Deficiência de Vitamina D/prevenção & controle , Proteína de Ligação a Vitamina D/genética , 25-Hidroxivitamina D 2/sangue , Adolescente , Adulto , Animais , Pão , Calcifediol/sangue , Criança , Colecalciferol/metabolismo , Colestanotriol 26-Mono-Oxigenase/metabolismo , Família 2 do Citocromo P450 , Dinamarca , Método Duplo-Cego , Estudos de Associação Genética , Humanos , Masculino , Pessoa de Meia-Idade , Leite , Estações do Ano , Pele/metabolismo , Terapia Ultravioleta , Deficiência de Vitamina D/sangue , Deficiência de Vitamina D/genética , Deficiência de Vitamina D/metabolismo , Proteína de Ligação a Vitamina D/metabolismo , Irradiação Corporal Total , Adulto JovemRESUMO
BACKGROUND: Vitamin D intakes are lower than dietary recommendations in most populations, and thus, a low vitamin D status is widespread, especially during winter. OBJECTIVE: We investigated the effects of increasing vitamin D intake to the recommended amount by fortification of milk and bread on serum 25-hydroxyvitamin D [25(OH)D] concentrations in families during winter in Denmark. DESIGN: The study was a randomized controlled trial in 782 children and adults (4-60 y old) recruited as 201 families. Families were randomly assigned to vitamin D-fortified or nonfortified milk and bread for 6 mo starting in September. The milk and bread replaced the participants' usual consumptions of products. RESULTS: Median (IQR) vitamin D intakes (habitual diet plus fortified products) were 9.4 mg/d (6.5, 12.3 mg/d) and 2.2 mg/d (1.5, 3.0 mg/d) in fortification and control groups, respectively. Geometric mean (IQR) serum 25(OH)D concentrations decreased from 73.1 nmol/L (61.9, 88.5 nmol/L) to 67.6 nmol/L (56.2, 79.4 nmol/L) in the fortification group and from 71.1 nmol/L (61.2, 85.9 nmol/L) to 41.7 nmol/L (29.5, 58.9 nmol/L) in the control group (both P , 0.001). The final 25(OH)D concentration was significantly higher in the fortification group than in the control group (P , 0.001). By the end of the study, ,1% of subjects in the fortification group and 25% of subjects in the control group had 25(OH)D concentrations ,30 nmol/L and 16% and 65% of subjects, respectively, had 25(OH)D concentrations ,50 nmol/L. CONCLUSION: Vitamin D fortification of milk and bread reduces the decrease in serum 25(OH)D concentrations during winter and ensures 25(OH)D concentrations .50 nmol/L in children and adults in Denmark.