The bioavailability of vitamin D3, a model hydrophobic nutraceutical, in casein micelles, as model protein nanoparticles: Human clinical trial results

•A clinical trial on bioavailability (BA) of VD3 in reformed casein micelles (rCM).•BA of VD3 in rCM was not significantly different from that in fat.•The presence of fat while VD3 was in rCM did not improve its BA.•Protein nanoparticles are effective carriers for hydrophobic nutraceuticals.