Vitamin D activity of food and supplements

The aim of the project is to assess the relative potency of each of the vitamin D active compounds in order to be able to calculate vitamin D activity through dietary intake, and to investigate the possibility of producing meat high in vitamin D.

Firstly, the potency of 25-hydroxyvitamin D3 relative to vitamin D3 will be investigated. This will include nutritional studies connected to ongoing feeding trials in pigs, and the initiation of a human intervention study i.e.

A feeding trial in slaughter pigs with vitamin D3 and 25-hydroxyvitamin D3. The end-points are vitamin D status assessed as 25-hydroxyvitamin D in serum and the content of vitamin D3 and 25-hydroxyvitamin D3 in meat.
A human intervention study with supplements of vitamin D3, vitamin D2 and 25-hydroxy vitamin D3, in which the end-points are vitamin D status and PTH.
A feeding trial in slaughter-pigs with vitamin D3 and 25-hydroxyvitamin D3 for further investigation of the impact of vitamin D in feed on vitamin D in food.

Secondly, quantification of dihydroxy vitamin D3 derivatives will be included in the quantification of the total activity of vitamin D via the dietary intake of pork meat. Stable isotope, 13C-labelled vitamin D3, will be used to assess bioavailability and to investigate if it is possible to produce meat high in vitamin D.