German health experts advise year‑round Vitamin D supplementation

In Germany, around 30 % of adults suffer from a Vitamin D deficiency and the German Nutrition Society estimates that 60 % have insufficient levels. Nutrition scientist Sophie Brünke explains that, despite longer daylight in summer, many people still do not obtain enough UVB exposure, so she recommends continuing Vitamin D supplementation throughout the year to support bone health, muscle function, metabolism and immunity.

There is debate over the appropriate dosage. The German Nutrition Society advises 800 IU (20 µg) per day for low‑sun exposure, while the UK’s NHS suggests 400 IU and the US NIH 600 IU. A nephrologist, Helena Orfanos‑Boeckel, argues that many individuals with skin type 2‑3 may need 4 000‑5 000 IU daily, alongside calcium, magnesium, boron and vitamin K2, to maintain optimal blood levels. She cautions that excessive active vitamin D (calcitriol) can release too much calcium from bone, so dosage should consider individual blood calcium and vitamin D ratios.