25-Hydroxyvitamin D3 1-alpha-HydroxylaseMilk SubstitutesCholesterol 7-alpha-Hydroxylase25-Hydroxyvitamin D 2CalcifediolVitamin DVitamin D DeficiencyCholecalciferolHydroxycholecalciferolsSteroid HydroxylasesDihydroxycholecalciferolsErgocalciferols24,25-Dihydroxyvitamin D 3Parathyroid HormoneCholestanetriol 26-MonooxygenaseCalcitriolVitamin D-Binding ProteinPhenylalanine HydroxylaseRicketsSunlightSteroid 21-HydroxylaseReceptors, CalcitriolSeasonsTryptophan HydroxylaseHydroxylationDietary SupplementsVitaminsTyrosine 3-MonooxygenaseCytochrome P-450 Enzyme SystemMixed Function OxygenasesProcollagen-Proline DioxygenasePhosphorusCalcium, DietaryOsteomalaciaCalciumBone DensityCross-Sectional StudiesNutritional StatusSkin PigmentationKidneyBone and BonesChromatography, High Pressure LiquidRisk FactorsBiological MarkersLinear ModelsProspective StudiesBone Density Conservation AgentsBenzopyrene Hydroxylasealpha 1-AntitrypsinKineticsAdrenal Hyperplasia, CongenitalCase-Control Studies4-Hydroxybenzoate-3-MonooxygenaseHypoxia-Inducible Factor 1, alpha SubunitDietEuropean Continental Ancestry GroupFood, FortifiedCholestenesDehydrocholesterolsPhosphatesCohort StudiesPrevalenceMass SpectrometryHypoparathyroidismBase SequenceMolecular Sequence DataRadioimmunoassayReceptors, Adrenergic, alphaNutritional RequirementsNutrition SurveysTandem Mass SpectrometryTime FactorsAfrican AmericansChromatography, LiquidDose-Response Relationship, DrugAdrenodoxinBody Mass IndexRNA, MessengerSpectrophotometry, UltravioletAbsorptiometry, PhotonBostonAlkaline PhosphataseHypercalcemiaNutrition PolicyOsteoporosisIntestinal AbsorptionCloning, MolecularFractures, BoneChickensPostmenopauseHypoxia-Inducible Factor-Proline DioxygenasesDouble-Blind MethodUnited StatesPhenylketonuriasNebraskaPregnancyRecombinant ProteinsHyperparathyroidism, SecondarySubstrate SpecificityGene Expression Regulation, Enzymologic