title: Incremental cholecalciferol supplementation up to 15 μg/d throughout winter at 51-55° N has no effect on biomarkers of cardiovascular risk in healthy young and older adults.
abstract: Two separate, identical, double-blind, randomized, placebo-controlled intervention studies were carried out in the south and north of Ireland (51-55°N). Men and women aged 20-40 y (n = 202) and ≥64 y (n = 192) received cholecalciferol at doses of 0 (P), 5 (D3-5), 10 (D3-10), or 15 (D3-15) μg/d (0-600 IU) during wintertime. Serum 25-hydroxyvitamin D [s25(OH)D], intact parathyroid hormone, systolic and diastolic blood pressure, fasting lipids, glucose and insulin, HOMA-IR, high-sensitivity CRP, matrix metalloproteinase-9, and its inhibitor (tissue inhibitor metalloproteinase-1) were measured at baseline (October) and 22 wk later at endpoint (March). Vitamin D receptor Fok I and Taq I genotypes were analyzed and dietary intakes of vitamin D and calcium were assessed. In young adults, s25(OH)D decreased from baseline to endpoint (P < 0.001), except in the D3-15 group, who maintained the baseline concentration of ~70 nmol/L. Older adults had lower s25(OH)D at baseline (median, 54.2 nmol/L) and concentrations increased in the D3-10 and D3-15 groups (P < 0.001). There were no significant effects of supplementation on cardiovascular disease (CVD) risk biomarkers in either age group. Fasting glucose and total and HDL cholesterol were lower (P < 0.05) in older adults with the Fok 1 ff genotype than in those with FF or Ff. Putative effects of vitamin D on cardio-metabolic health will only be evident at higher intakes than the current RDA and possibly in individuals at particular risk of low s25(OH)D and/or CVD risk.
authors: Vitamin D Research Group, School of Food and Nutritional Sciences, University College, Cork, Ireland.
authors: Siobhan
authors: S
authors: Muldowney
authors: Alice J
authors: AJ
authors: Lucey
authors: Tom R
authors: TR
authors: Hill
authors: Kelly M
authors: KM
authors: Seamans
authors: Nicola
authors: N
authors: Taylor
authors: Julie M W
authors: JM
authors: Wallace
authors: Geraldine
authors: G
authors: Horigan
authors: Maria S
authors: MS
authors: Barnes
authors: Maxine P
authors: MP
authors: Bonham
authors: Emeir M
authors: EM
authors: Duffy
authors: J J
authors: JJ
authors: Strain
authors: Kevin D
authors: KD
authors: Cashman
authors: Mairead
authors: M
authors: Kiely
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology*; D015415:Biomarkers; D002318:Cardiovascular Diseases / Q000517:prevention & control*; D002762:Cholecalciferol / Q000008:administration & dosage* / Q000494:pharmacology*; D019587:Dietary Supplements; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D012621:Seasons; D014815:Vitamins / Q000008:administration & dosage / Q000494:pharmacology; D055815:Young Adult
chemical_list: D015415:Biomarkers; D014815:Vitamins; D002762:Cholecalciferol