In contrast to vitamin D from sunlight, dietary vitamin D is
available during any season and offers a reliable source of the
vitamin for individuals who do not have access to sunlight
exposure. Oily fi sh is the most important dietary source of
vitamin D [1], whereas most other foods from animal origin
contain very low amounts and do not signi ficantly contribute to
an improvement of vitamin D status. A recent study was able to
ascertain UVB exposure of hens as a highly effective approach to
increase the vitamin D content in eggs [2]. Data from that study
showed that UVB radiation increased the vitamin D content
much stronger than feeding the maximum permissible dosages
of dietary vitamin D