title: Maintenance of wintertime vitamin D status with cholecalciferol supplementation is not associated with alterations in serum cytokine concentrations among apparently healthy younger or older adults.
abstract: Epidemiological studies have shown that low vitamin D status results in impaired immune function and is associated with the prevalence of autoimmune and inflammatory conditions. Vitamin D supplementation has been shown to reduce circulating concentrations of inflammatory markers in such conditions. However, the possible beneficial effect of vitamin D supplementation in the general population, particularly for those individuals living at high latitudes where hypovitaminosis D is common during wintertime, remains unclear. The aim of this study was to assess the effect of vitamin D supplementation using doses of 5, 10, and 15 μg/d cholecalciferol (D3) compared with placebo on cytokine concentrations throughout winter in apparently healthy younger (aged 20-40 y) and older (aged ≥64 y) adults. A total of 211 younger and 202 older adults completed the 22-wk intervention (from October to March) with >85% compliance. Serum concentrations of 25-hydroxycholecalciferol [25(OH)D3], high sensitivity C-reactive protein, IL-6, IL-10, soluble CD40 ligand, TGFβ, TNFα, and fibrinogen were measured using ELISA. 25(OH)D3 concentrations significantly decreased in the placebo and 5 and 10/d μg D3 groups in the younger cohort and in the placebo group in the older cohort. Whereas 15 μg/d D3 supplementation maintained 25(OH)D3 concentrations in the younger cohort (baseline, 75.9 nmol/L; postintervention, 69.0 nmol/L) and significantly increased concentrations in the older cohort (baseline, 55.1 nmol/L; postintervention, 73.9 nmol/L), it had no significant effect on cytokine concentrations (ANCOVA, P > 0.05). The long-term effects of low vitamin D status remain to be elucidated and optimization of vitamin D status in otherwise healthy individuals may potentially have lasting beneficial effects on the immune system.
authors.affiliation: Northern Ireland Centre for Food and Health, University of Ulster, Coleraine, BT52 1SA, Republic of Ireland.
authors.forename: Maria S
authors.initials: MS
authors.lastname: Barnes
authors.forename: Geraldine
authors.initials: G
authors.lastname: Horigan
authors.forename: Kevin D
authors.initials: KD
authors.lastname: Cashman
authors.forename: Tom R
authors.initials: TR
authors.lastname: Hill
authors.forename: L Kirsty
authors.initials: LK
authors.lastname: Forsythe
authors.forename: Alice J
authors.initials: AJ
authors.lastname: Lucey
authors.forename: Emeir M
authors.initials: EM
authors.lastname: McSorley
authors.forename: Mairead
authors.initials: M
authors.lastname: Kiely
authors.forename: Maxine P
authors.initials: MP
authors.lastname: Bonham
authors.forename: Pamela J
authors.initials: PJ
authors.lastname: Magee
authors.forename: J J
authors.initials: JJ
authors.lastname: Strain
authors.forename: Julie M W
authors.initials: JM
authors.lastname: Wallace
mesh_terms: D000209:Acute-Phase Proteins / Q000032:analysis; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging; D015415:Biomarkers / Q000097:blood; D002112:Calcifediol / Q000097:blood; D002762:Cholecalciferol / Q000008:administration & dosage / Q000627:therapeutic use*; D015331:Cohort Studies; D016207:Cytokines / Q000097:blood*; D019587:Dietary Supplements; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D055118:Medication Adherence; D008875:Middle Aged; D009752:Nutritional Status; D012621:Seasons; D014808:Vitamin D Deficiency / Q000097:blood / Q000276:immunology / Q000517:prevention & control*; D055815:Young Adult
chemical_list: D000209:Acute-Phase Proteins; D015415:Biomarkers; D016207:Cytokines; D002762:Cholecalciferol; D002112:Calcifediol