The bioavailability of vitamin D from fortified cheeses and supplements is equivalent in adults.
Wagner D, Sidhom G, Whiting SJ, Rousseau D, Vieth R.
J Nutr. 2008 Jul;138(7):1365-71.
PMID: 18567762
Compared with baseline, serum parathyroid hormone decreased with both fortification (P = 0.003) and supplementation (P = 0.012). These data demonstrate that vitamin D is equally bioavailable from fortified hard cheeses and supplements, making cheese suitable for vitamin D fortification.