High Levels of Vitamin D Linked to Increased Risk of Death

There is now ample evidence showing that vitamin D has  many health benefits, however new research suggests that high levels of the vitamin may not be as healthy as was thought. Darshana Durup, a PhD student at the University of Copenhagen (Denmark), and colleagues analysed data of 247,574 people who had blood samples stored at the Copenhagen General Practitioners Laboratory. Unsurprisingly, results showed that the mortality rate in people whose blood contained deficient levels of vitamin D (less than 10 nmol of vitamin D per liter of serum) was 2.31 times higher than in those with 50 nmol of vitamin D per liter of serum – the optimal amount in terms of mortality risk. However, the scientists were surprised to find that the mortality rate in people with more than 140 nmol of vitamin D per liter of serum was also increased, by a factor of 1.42. The researchers emphasize that they are unaware of why having higher levels of the vitamin would cause an increased risk of dying, however they add that the results can be used to question the wisdom of people recommending that people take large doses of supplementary vitamin D. Durup concluded: "It is important to conduct further studies in order to understand the relationship. A lot of research has been conducted on the risk of vitamin D deficiency. However, there is no scientific evidence for a ‘more is better’ argument for vitamin D, and our study does not support the argument either. We hope that our study will inspire others to study the cause of higher mortality with a high level of vitamin D."