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
Vitamin D, for example, does more than ‘just’ ensuring bone health. Studies link vitamin D deficiency with, for example, hypertension, insulin resistance, type 2 diabetes and dyslipidaemia. A recent Brazilian study, for example, enrolled 137 people aged at least 60 years who attended an out-patient cardiology clinic. Of these, 65% were deficient in vitamin D – defined as blood 25-hydroxyvitamin D (25[OH]D) levels less than 30 ng/mL. The risk of heart failure was about 12 times (odds ratio [OR] 12.19) greater in vitamin D deficient people than controls. Indeed, the risk associated with vitamin D deficiency was greater than that associated with obesity (OR 4.17) or cardiac arrhythmia (OR 3.69)3.