Influence of food matrix delivery system on the bioavailability of vitamin D₃: a randomized crossover trial in postmenopausal women.

Objectives. Vitamin D insufficiency (blood 25-hydroxyvitamin D <50 nmol/L) is a global health problem. Vitamin D food fortification might be a solution, but knowledge is sparse on which food matrices yield the highest bioavailability. The aim of this study was to investigate the influence of different food matrices including complex formations with whey proteins on the human bioavailability of vitamin D. Methods. In this randomized, multiple crossover trial, we enrolled 30 postmenopausal women 60 to 80 y of age with vitamin D insufficiency. We measured changes in serum concentrations of vitamin D₃ (D₃) postprandially for 24 h in response to the intake of 500mL of different food matrices with 200 µg D₃ added compared with a control (500mL of water). Foods included apple juice with whey protein isolate (WPI), apple juice, semi-skim milk, and water (with D₃). The food matrices were provided in a...