title: Oral spray wintertime vitamin D3supplementation has no impact on inflammation in Gaelic footballers.
abstract: Vitamin D inadequacy [total 25(OH)D <50 nmol/L] is widespread in athletes. The biologically active metabolite, 1,25-dihydroxyvitamin D, may be involved in regulating inflammation although in vitro findings have not been consistently replicated in human intervention trials. This study, conducted at a latitude of 55°N, aimed to assess inflammatory biomarkers in Gaelic footballers before and after a wintertime vitamin D3intervention. Samples from a 12-week double-blind, randomized, placebo-controlled trial, in which 42 Gaelic footballers received 3000 IU (75 μg) vitamin D3daily or placebo via oral spray solutions, were analysed for a range of inflammatory biomarkers. Cytokines (interleukin-8 and tumor necrosis factor-α), cathelicidin and high sensitivity C-reactive protein were quantified by multiplex assay, enzyme-linked immunosorbent assay and clinical biochemistry, respectively. White blood cell, lymphocyte, and neutrophil concentrations were determined by full blood profile. Data on total 25-hydroxyvitamin D, measured by LC-MS/MS, were available from the previous study. Vitamin D3supplementation significantly increased mean total 25-hydroxyvitamin D concentrations from 47 to 84 nmol/L (P = 0.006); yet this had no effect on white blood cell count (P = 0.699), lymphocyte (P = 0.694), neutrophil (P = 0.594), interleukin-8 (P = 0.334), tumor necrosis factor-α (P = 0.587), cathelicidin (P = 0.745) or high sensitivity C-reactive protein concentration (P = 0.621) compared to placebo. 12-weeks vitamin D3supplementation did not impact the immune profile of Gaelic footballers. This is likely because biomarkers were within their respective normal range or at a concentration similar to that of the general population at baseline. Future studies are encouraged to use inflammation as their primary outcome measure and recruit athletes at risk of compromised immunity.
authors.affiliation: Northern Ireland Centre for Food and Health, University of Ulster, Coleraine, Northern Ireland.
authors.forename: J J
authors.initials: JJ
authors.lastname: Todd
authors.affiliation: Northern Ireland Centre for Food and Health, University of Ulster, Coleraine, Northern Ireland.
authors.forename: E M
authors.initials: EM
authors.lastname: McSorley
authors.affiliation: Northern Ireland Centre for Food and Health, University of Ulster, Coleraine, Northern Ireland.
authors.forename: L K
authors.initials: LK
authors.lastname: Pourshahidi
authors.affiliation: Irish Institute of Sport, Dublin, Ireland.
authors.forename: S M
authors.initials: SM
authors.lastname: Madigan
authors.affiliation: Northern Ireland Centre for Food and Health, University of Ulster, Coleraine, Northern Ireland.
authors.forename: W
authors.initials: W
authors.lastname: Crowe
authors.affiliation: School of Biochemistry and Immunology, Trinity College, Dublin, Ireland.
authors.forename: E J
authors.initials: EJ
authors.lastname: Laird
authors.affiliation: Department of Biochemistry, Central Pathology Laboratory, St. James's Hospital, Dublin, Ireland.
authors.forename: M
authors.initials: M
authors.lastname: Healy
authors.affiliation: Sport and Exercise Sciences Research Institute, University of Ulster, Jordanstown, Northern Ireland.
authors.forename: A
authors.initials: A
authors.lastname: McNeilly
authors.affiliation: Northern Ireland Centre for Food and Health, University of Ulster, Coleraine, Northern Ireland.
authors.forename: P J
authors.initials: PJ
authors.lastname: Magee
mesh_terms: D023181:Antimicrobial Cationic Peptides / Q000097:blood; D015415:Biomarkers / Q000097:blood; D002097:C-Reactive Protein / Q000032:analysis; D002762:Cholecalciferol / Q000008:administration & dosage*; D016207:Cytokines / Q000097:blood; D019587:Dietary Supplements; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007249:Inflammation / Q000097:blood*; D016209:Interleukin-8 / Q000097:blood; D007958:Leukocyte Count; D008297:Male; D058993:Oral Sprays; D010101:Oxygen Consumption; D012621:Seasons; D012916:Soccer / Q000502:physiology*; D064133:Sports Nutritional Physiological Phenomena; D014409:Tumor Necrosis Factor-alpha / Q000097:blood; D014807:Vitamin D / Q000031:analogs & derivatives / Q000097:blood; D055815:Young Adult; D054804:Cathelicidins
chemical_list: D023181:Antimicrobial Cationic Peptides; D015415:Biomarkers; C508606:CXCL8 protein, human; D016207:Cytokines; D016209:Interleukin-8; D058993:Oral Sprays; D014409:Tumor Necrosis Factor-alpha; D014807:Vitamin D; D002762:Cholecalciferol; D002097:C-Reactive Protein; C104450:25-hydroxyvitamin D; D054804:Cathelicidins
keywords: athletes; inflammation; oral spray; supplementation; vitamin D