milk that was enriched with vitamin D by exposing it to ultraviolet radiation, formed a tasteful alternative for cod-liver oil
UV-radiated milk
Until the first decades of the 20th century rachitis
(or rickets) formed a wide spread disease, caused
by a lack of vitamin D. A regular consumption of a
limited quantity of cod-liver oil had proven to be
effective already since 1918 although vitamin D as
the crucial ingredient would only be identified in
1922. In 1919 de German scientist K. Huldschinsky
was the first who succeeded in curing children from
rachitis by treating them with artificial generated
ultraviolet radiation. Especially UV-B stimulates the
production of new pigment and it converts
cholesterol into vitamin D. Through our liver and
kidneys this vitamin is converted into a hormone
that makes our bones to absorb calcium. From 1920
on, milk that was enriched with vitamin D by
exposing it to ultraviolet radiation from strong
high-pressure mercury vapour arc discharge lamps
formed a more tasteful alternative for the cod-liver
oil. For they who could afford it, a more effective direct treatment of the skin with
ultraviolet radiation remained the favourite. From the mid of the 20th century the
circumstances for living and other eating habits guaranteed the consumption of the
necessary quantities of vitamin D but especially during the winter period an additional
exposure to some ultraviolet radiation was still assumed to be in favour of general