title: Effects of vitamin D2-fortified bread v. supplementation with vitamin D2 or D3 on serum 25-hydroxyvitamin D metabolites: an 8-week randomised-controlled trial in young adult Finnish women.
abstract: There is a need for food-based solutions for preventing vitamin D deficiency. Vitamin D3 (D3) is mainly used in fortified food products, although the production of vitamin D2 (D2) is more cost-effective, and thus may hold opportunities. We investigated the bioavailability of D2 from UV-irradiated yeast present in bread in an 8-week randomised-controlled trial in healthy 20-37-year-old women (n 33) in Helsinki (60°N) during winter (February-April) 2014. Four study groups were given different study products (placebo pill and regular bread=0 µg D2 or D3/d; D2 supplement and regular bread=25 µg D2/d; D3 supplement and regular bread=25 µg D3/d; and placebo pill and D2-biofortified bread=25 µg D2/d). Serum 25-hydroxyvitamin D2 (S-25(OH)D2) and serum 25-hydroxyvitamin D3 (S-25(OH)D3) concentrations were measured at baseline, midpoint and end point. The mean baseline total serum 25-hydroxyvitamin D (S-25(OH)D=S-25(OH)D2+S-25(OH)D3) concentration was 65·1 nmol/l. In repeated-measures ANCOVA (adjusted for baseline S-25(OH)D as total/D2/D3), D2-bread did not affect total S-25(OH)D (P=0·707) or S-25(OH)D3 (P=0·490), but increased S-25(OH)D2 compared with placebo (P<0·001). However, the D2 supplement was more effective than bread in increasing S-25(OH)D2 (P<0·001). Both D2 and D3 supplementation increased total S-25(OH)D compared with placebo (P=0·030 and P=0·001, respectively), but D2 supplementation resulted in lower S-25(OH)D3 (P<0·001). Thus, D2 from UV-irradiated yeast in bread was not bioavailable in humans. Our results support the evidence that D2 is less potent in increasing total S-25(OH)D concentrations than D3, also indicating a decrease in the percentage contribution of S-25(OH)D3 to the total vitamin D pool.
authors: 1Calcium Research Unit,Department of Food and Environmental Sciences,Division of Nutrition,PO Box 66,University of Helsinki,FI-00014 Helsinki,Finland.
authors: Suvi T
authors: ST
authors: Itkonen
authors: 1Calcium Research Unit,Department of Food and Environmental Sciences,Division of Nutrition,PO Box 66,University of Helsinki,FI-00014 Helsinki,Finland.
authors: Essi
authors: E
authors: Skaffari
authors: 1Calcium Research Unit,Department of Food and Environmental Sciences,Division of Nutrition,PO Box 66,University of Helsinki,FI-00014 Helsinki,Finland.
authors: Pilvi
authors: P
authors: Saaristo
authors: 1Calcium Research Unit,Department of Food and Environmental Sciences,Division of Nutrition,PO Box 66,University of Helsinki,FI-00014 Helsinki,Finland.
authors: Elisa M
authors: EM
authors: Saarnio
authors: 1Calcium Research Unit,Department of Food and Environmental Sciences,Division of Nutrition,PO Box 66,University of Helsinki,FI-00014 Helsinki,Finland.
authors: Maijaliisa
authors: M
authors: Erkkola
authors: 2Division of Food Technology,National Food Institute,Technical University of Denmark,2860 Soborg,Denmark.
authors: Jette
authors: J
authors: Jakobsen
authors: 3School of Food and Nutritional Sciences,Cork Centre for Vitamin D and Nutrition Research,University College Cork,T12 E31 Cork,Republic of Ireland.
authors: Kevin D
authors: KD
authors: Cashman
authors: 1Calcium Research Unit,Department of Food and Environmental Sciences,Division of Nutrition,PO Box 66,University of Helsinki,FI-00014 Helsinki,Finland.
authors: Christel
authors: C
authors: Lamberg-Allardt
mesh_terms: D000328:Adult; D001682:Biological Availability; D001939:Bread / Q000032:analysis* / Q000382:microbiology; D002118:Calcium / Q000097:blood; D002762:Cholecalciferol / Q000008:administration & dosage* / Q000493:pharmacokinetics; D019587:Dietary Supplements; D004872:Ergocalciferols / Q000008:administration & dosage* / Q000032:analysis / Q000493:pharmacokinetics; D005260:Female; D005387:Finland; D005527:Food, Fortified / Q000382:microbiology; D006801:Humans; D010281:Parathyroid Hormone / Q000097:blood; D010919:Placebos; D012441:Saccharomyces cerevisiae / Q000737:chemistry / Q000528:radiation effects; D012621:Seasons; D014466:Ultraviolet Rays; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D055815:Young Adult
chemical_list: D004872:Ergocalciferols; D010281:Parathyroid Hormone; D010919:Placebos; D014807:Vitamin D; D002762:Cholecalciferol; C104450:25-hydroxyvitamin D; D002118:Calcium
keywords: 25-Hydroxyvitamin D; 25-Hydroxyvitamin D2; 25-Hydroxyvitamin D3; Bioavailability; D2
                  vitamin D2; D3
                  vitamin D3; S-25(OH)D serum 25-hydroxyvitamin D; S-25(OH)D2
                  serum 25-hydroxyvitamin D2; S-25(OH)D3
                  serum 25-hydroxyvitamin D3; S-PTH serum parathyroid hormone; UV-irradiated yeast; Vitamin D2; Vitamin D3