February 2015

Dietary Fat Increased Vitamin D-3 Absorption

Researchers at Tufts University developed a study to evaluate conditions under which Vitamin D-3 is best absorbed. Past research suggests that Vitamin D-3 taken with a meal has been shown to increase serum levels greater than Vitamin D-3 taken during a fasting period. The components of a meal which most effectively allows for the absorption of Vitamin D-3, however, has yet to be determined. D-3 supplements taken with fat have been suggested to increase serum levels greater than meals without fat but this discovery is not thorough enough for Tufts.

The purposes of this study were to further prove that fat intake at a meal can improve or influence Vitamin D-3 supplementation absorption and investigate whether MUFA (monounsaturated fatty acid):PUFA (polyunsaturated fatty acid) ratios had any influence on absorption. 

50 men and women were recruited for the single blind study during the least sunny months of the year (October-May) as to only allow D-3 from supplementation to effect serum levels. Vitamin D-3 supplements were purchased from BioTech Pharmacal Inc. and analyzed by Covance to determine they contained 55,905 IU of Vitamin D-3. Subjects were instructed to fast for 12 hours before attending breakfast the next morning. 19 subjects were in a fat-free meal group, 11 were in the high MUFA:PUFA (4:1) meal group, and 20 in the low MUFA:PUFA (1:4) meal group. The MUFA:PUFA ratio was manipulated by adding olive oil (MUFA) and corn oil (PUFA) to meals to achieve the desired ratios. Dramatic ratios were used to enhance the likelihood of detecting a difference in the two groups if one were present. Subjects were provided breakfast, followed by the D-3 supplementation, in addition to lunch and dinner. Serum levels of D-3 were tested via blood draw at baseline (before breakfast), 10, 12, and 14 hours after the supplement dose.

The analyses of vitamin D levels at baseline and follow-up points after supplementation, demonstrated there was a significant (P<0.001) influence of meals containing fat on D-3 serum levels versus meals served without fat. Those who ate the meals containing fat had higher serum levels of D-3 at each follow-up point after baseline. 

However, plasma levels of D-3 did not differ significantly at any time between the two high-fat meal groups with the differing MUFA:PUFA ratios. We can infer based on this study, that the ratio of MUFA:PUFA does not influence the absorption of the Vitamin D-3 supplement.

Article: http://www.andjrnl.org/article/S2212-2672(14)01468-3/pdf?dialogRequest=

Supplemental Article: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3235461/pdf/IJE2011-809069.pdf