Dietary fat increases vitamin D-3 absorption.
Level 2 - randomized trial
Individual randomized controlled comparative trial.
PubMed 25441954 · doi:10.1016/j.jand.2014.09.014
What was done
Fifty healthy older men and women were randomly assigned to one of three breakfast meal groups following a 12-hour fast: a fat-free meal, a meal with 30% of energy from fat with a low monounsaturated-to-polyunsaturated fatty acid ratio (MUFA:PUFA 1:4), or a meal with 30% fat with a high MUFA:PUFA ratio (4:1). All participants consumed a single 50,000 IU vitamin D-3 supplement with their meal. Plasma vitamin D-3 was measured using liquid chromatography-mass spectrometry at baseline, 10, 12, and 14 hours post-dose.
What was found
Peak plasma vitamin D-3 concentrations at 12 hours were 32% higher (95% CI, 11% to 52%; P = 0.003) in participants who consumed fat-containing meals compared to those who consumed fat-free meals. There were no statistically significant differences in plasma vitamin D-3 absorption across time points between the high-MUFA and low-MUFA meal groups.
Why it matters
These findings show that dietary fat substantially improves the acute absorption of supplemental vitamin D-3, whereas the specific fatty acid composition (MUFA vs. PUFA) does not appear to alter absorption.
Limits
The study evaluated only a single large dose (50,000 IU) over a 14-hour window, rather than daily physiological doses or long-term 25-hydroxyvitamin D status. The sample size was small (n = 50), limited to older adults, and used an open-label design.
Cited by
- supports Fat-soluble vitamins and phytonutrients like curcumin require dietary fat for optimal absorption.