title: Dietary vitamin D during pregnancy has dose-dependent effects on long bone density and architecture in guinea pig offspring but not the sows.
abstract: BACKGROUND
  The effects of vitamin D during pregnancy on maternal and neonatal bone health remain unclear.
  
  
  OBJECTIVE
  This study was designed to test whether dietary vitamin D dose-dependently affects maternal and neonatal bone health.
  
  
  METHODS
  Female guinea pigs (n = 45; 4 mo old) were randomly assigned at mating to receive 1 of 5 doses of vitamin D3 (cholecalciferol; 0, 0.25, 0.5, 1, or 2 IU/g diet) throughout pregnancy. Plasma vitamin D metabolites, mineral homeostasis, bone biomarkers, and bone mass were tested in sows throughout pregnancy and in 2-d-old pups. Microarchitecture and histology of excised bone were conducted postpartum.
  
  
  RESULTS
  By 3 wk of pregnancy, plasma 25-hydroxyvitamin D [25(OH)D] followed a positive dose-response, whereas 1,25-dihydroxyvitamin D [1,25(OH)2D] reached a plateau if vitamin D was ≥0.5 IU/g diet. Weight gain, areal bone mineral density (aBMD), volumetic bone mineral density (vBMD), and bone biomarkers did not differ among maternal groups. A positive dose-response was observed for mean ± SEM pup plasma concentrations of 25(OH)D (10.5 ± 1.50 to 113 ±11.6 nmol/L) and 1,25(OH)2D (123 ± 13.8 to 544 ± 53.3 pmol/L). Pup weight, plasma minerals, and osteocalcin were not different; plasma deoxypyridinoline was lower in the 1- and 0.25-IU/g groups than in all other groups. Pup femur aBMD was higher (9.2-13%; P = 0.04) in the 2-IU/g group than in all other groups except for the 0-IU/g group. Tibia and femur vBMD of pups responded to maternal diet in a U-shaped pattern. The femoral growth plate was 7.9% wider in the 0-IU/g group than in the 1-IU/g group.
  
  
  CONCLUSIONS
  Maternal vitamin D supplementation dose-dependently altered pup long bone architecture and mineral density in a manner similar to vitamin D deficient rickets whereas maternal bone was stable. These data reinforce that inadequate maternal vitamin D intake may compromise neonatal bone health and that exceeding recommendations is not advantageous.
authors.affiliation: School of Dietetics and Human Nutrition, McGill University, Ste-Anne-de-Bellevue, Canada;
authors.forename: Negar
authors.initials: N
authors.lastname: Tabatabaei
authors.affiliation: Department of Pediatrics and Child Health, University of Manitoba, Winnipeg, Canada;
authors.forename: Celia J
authors.initials: CJ
authors.lastname: Rodd
authors.affiliation: Faculty of Medicine, Calcium Research Laboratory.
authors.forename: Richard
authors.initials: R
authors.lastname: Kremer
authors.affiliation: Faculty of Dentistry.
authors.forename: Zohreh
authors.initials: Z
authors.lastname: Khavandgar
authors.affiliation: Department of Medicine and Faculty of Dentistry, McGill University, Montreal, Canada.
authors.forename: Monzur
authors.initials: M
authors.lastname: Murshed
authors.affiliation: School of Dietetics and Human Nutrition, McGill University, Ste-Anne-de-Bellevue, Canada; hope.weiler@mcgill.ca.
authors.forename: Hope A
authors.initials: HA
authors.lastname: Weiler
mesh_terms: D015502:Absorptiometry, Photon; D000818:Animals; D015415:Biomarkers / Q000097:blood; D015519:Bone Density / Q000187:drug effects*; D002118:Calcium / Q000097:blood; D002762:Cholecalciferol / Q000008:administration & dosage* / Q000097:blood*; D004032:Diet; D004305:Dose-Response Relationship, Drug; D005260:Female; D006168:Guinea Pigs; D008297:Male; D039382:Maternal Nutritional Physiological Phenomena; D023421:Models, Animal; D011247:Pregnancy; D064167:Recommended Dietary Allowances; D014131:Trace Elements / Q000097:blood
chemical_list: D015415:Biomarkers; D014131:Trace Elements; D002762:Cholecalciferol; D002118:Calcium
keywords: bone; dose-response; guinea pig; pregnancy; vitamin D