Dietary fat increases vitamin D-3 absorption

J Acad Nutr Diet. 2015 Feb;115(2):225-230. doi: 10.1016/j.jand.2014.09.014. Epub 2014 Nov 17.


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.

Objectives: 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).

Design: Open, three-group, single-dose vitamin D-3 comparative absorption experiment.

Participants/setting: 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.

Main outcome measures: Plasma vitamin D-3 was measured by liquid chromatography-mass spectrometry before and 10, 12 (the expected peak), and 14 hours after the dose.

Statistical analyses performed: 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.

Keywords: Absorption; Healthy adults; Meal conditions; Vitamin D-3; Vitamin D-3 supplementation.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Aged
  • Cholecalciferol / administration & dosage
  • Cholecalciferol / blood*
  • Cholecalciferol / pharmacokinetics*
  • Dietary Fats / administration & dosage*
  • Dietary Proteins / administration & dosage
  • Dietary Supplements*
  • Fatty Acids, Monounsaturated / administration & dosage
  • Fatty Acids, Unsaturated / administration & dosage
  • Female
  • Humans
  • Male
  • Meals
  • Middle Aged
  • Nutrition Assessment
  • Single-Blind Method


  • Dietary Fats
  • Dietary Proteins
  • Fatty Acids, Monounsaturated
  • Fatty Acids, Unsaturated
  • Cholecalciferol