Vitamin D, sunshine and UVB
phototherapy were first reported in the early 1900s to control
psoriasis, cure
rickets and cure
tuberculosis (TB).
Vitamin D also controlled
asthma and
rheumatoid arthritis with intakes ranging from 60,000 to 600,000 International Units (IU)/day. In the 1980s, interest in treating
psoriasis with
vitamin D rekindled. Since 1985 four different oral forms of
vitamin D (D2, D3, 1-hydroxyvitaminD3 (1(
OH)D3) and 1,25-dihydroxyvitaminD3 (
calcitriol)) and several topical formulations have been reported safe and effective treatments for
psoriasis-as has UVB
phototherapy and sunshine. In this review we show that many pre-treatment serum 25(
OH)D concentrations fall within the current range of normal, while many post-treatment concentrations fall outside the upper limit of this normal (100 ng/mL). Yet,
psoriasis patients showed significant clinical improvement without complications using these treatments. Current estimates of
vitamin D sufficiency appear to underestimate serum 25(
OH)D concentrations required for optimal health in
psoriasis patients, while concentrations associated with adverse events appear to be much higher than current estimates of safe serum 25(
OH)D concentrations. Based on these observations, the therapeutic index for
vitamin D needs to be reexamined in the treatment of
psoriasis and other diseases strongly linked to
vitamin D deficiency, including
COVID-19 infections, which may also improve safely with sufficient
vitamin D intake or UVB exposure.