Figure 1: Vitamin D is a fat-soluble vitamin. Few foods naturally contain vitamin D, so dermal synthesis after UVB radiation remains the major route to obtain vitamin D. 7-dehydrocholesterol in skin epidermal cells is converted after UVB radiation into pre-vitamin D. Both vitamin D3 and undergo further enzymatic conversion to its active forms. First, it undergoes 25-hydroxylation in liver to 25(OH)D (calcidiol), then it is converted in kidneys through 1-alpha-hydroxylation to its most active form, 1,25(OH)2D (calcitriol)
Tables at a glance
Figures at a glance