Rickets was the archetypal scourge of Victorian slums. But even in the 1930s, some 80% of children in London and Durham still showed rickets1. We now know why: a lack of vitamin D.
In 1919, Kurt Huldschinsky, a Berlin paediatrician, cured advanced rickets using artificial ultraviolet (UV) light. He then exposed one arm of a child with rickets to UV. X-rays showed that bone health improved in both arms. He concluded that skin irradiation released a chemical – now called vitamin D - into the blood2. Recent studies show that some supplements, such as vitamin D, support health across a growing range of diseases – but also warn that some may be harmful