Vitamin D deficiency constitutes a largely unrecognized and
widespread public health problem. It has been suggested that 1
billion p eople worldwide have vitamin D deficien cy or
insufficiency. 1,2
Humans get vitamin D from sunlight exposure
an d f ro m t heir fo od s o r diet a r y s u pp lem e nt s. Sea s on al
variations of UVB light exposure, increasing indoor activities,
stationary care in nursing homes, and the frequent use of
sunscreens to reduce the risk of skin cancer are the main causes
for the low synthesis of cutaneous vitamin D. Thus, an
increasing number of people depend on dietary sources of
vitamin D. On the other hand, vitamin D is found naturally in
only a few foods. Besides fish and milk, eggs, particularly egg
yolks, are considered to be the important food source of
vitamin D.3