title: Dietary fat increases vitamin D-3 absorption.
abstract: BACKGROUND
  The plasma 25-hydroxyvitamin D response to supplementation with vitamin D varies widely, but vitamin D absorption differences based on diet composition is poorly understood.
  
  
  OBJECTIVE
  We tested the hypotheses that absorption of vitamin D-3 is greater when the supplement is taken with a meal containing fat than with a fat-free meal and that absorption is greater when the fat in the meal has a higher monounsaturated-to-polyunsaturated fatty acid ratio (MUFA:PUFA).
  
  
  METHODS
  Open, three-group, single-dose vitamin D-3 comparative absorption experiment.
  
  
  METHODS
  Our 1-day study was conducted in 50 healthy older men and women who were randomly assigned to one of three meal groups: fat-free meal, and a meal with 30% of calories as fat with a low (1:4) and one with a high (4:1) MUFA:PUFA. After a 12-hour fast, all subjects took a single 50,000 IU vitamin D-3 supplement with their test breakfast meal.
  
  
  METHODS
  Plasma vitamin D-3 was measured by liquid chromatography-mass spectrometry before and 10, 12 (the expected peak), and 14 hours after the dose.
  
  
  METHODS
  Means were compared with two-tailed t tests for independent samples. Group differences in vitamin D-3 absorption across the measurement time points were examined by analysis of variance with the repeated measures subcommand of the general linear models procedure.
  
  
  RESULTS
  The mean peak (12-hour) plasma vitamin D-3 level after the dose was 32% (95% CI 11% to 52%) greater in subjects consuming fat-containing compared with fat-free meals (P=0.003). Absorption did not differ significantly at any time point in the high and low MUFA and PUFA groups.
  
  
  CONCLUSIONS
  The presence of fat in a meal with which a vitamin D-3 supplement is taken significantly enhances absorption of the supplement, but the MUFA:PUFA of the fat in that meal does not influence its absorption.
authors.forename: Bess
authors.initials: B
authors.lastname: Dawson-Hughes
authors.forename: Susan S
authors.initials: SS
authors.lastname: Harris
authors.forename: Alice H
authors.initials: AH
authors.lastname: Lichtenstein
authors.forename: Gregory
authors.initials: G
authors.lastname: Dolnikowski
authors.forename: Nancy J
authors.initials: NJ
authors.lastname: Palermo
authors.forename: Helen
authors.initials: H
authors.lastname: Rasmussen
mesh_terms: D000368:Aged; D002762:Cholecalciferol / Q000008:administration & dosage / Q000097:blood* / Q000493:pharmacokinetics*; D004041:Dietary Fats / Q000008:administration & dosage*; D004044:Dietary Proteins / Q000008:administration & dosage; D019587:Dietary Supplements; D005229:Fatty Acids, Monounsaturated / Q000008:administration & dosage; D005231:Fatty Acids, Unsaturated / Q000008:administration & dosage; D005260:Female; D006801:Humans; D008297:Male; D062407:Meals; D008875:Middle Aged; D015596:Nutrition Assessment; D016037:Single-Blind Method
chemical_list: D004041:Dietary Fats; D004044:Dietary Proteins; D005229:Fatty Acids, Monounsaturated; D005231:Fatty Acids, Unsaturated; D002762:Cholecalciferol
keywords: Absorption; Healthy adults; Meal conditions; Vitamin D-3; Vitamin D-3 supplementation