Vitamin D that comes from fortified foods and is also synthesized in the body when we’re exposed to sunshine contributes to overall health and well-being. Researchers are trying to pinpoint just how much of the vitamin, which is actually a hormone, the body needs to prevent disease and live a longer life. But now questions are raised about whether too much vitamin D could lead to early death, based on a large study that included a quarter of a million people.
Copenhagen study finds higher death rates linked to too much vitamin D
Vitamin D has long been linked to bone health, especially in postmenopausal women.
As information emerges from observational studies, it seems keeping levels higher – and maybe a bit higher than recommended – can confer other health benefits such as thwarting cancer, boosting immunity, fighting depression and protecting from heart disease.
Now researchers find higher levels of vitamin D seems to be associated with higher mortality; found when they looked at blood samples from 247,574 Copenhageners.
The study was conducted by the Faculty of Health and Medical Sciences at the University of Copenhagen.
Darshana Durup, a PhD student said in a media release, “We have had access to blood tests from a quarter of a million Copenhageners. We found higher mortality in people with a low level of vitamin D in their blood, but to our surprise, we also found it in people with a high level of vitamin D. We can draw a graph showing that perhaps it is harmful with too little and too much vitamin D."
The answer to how much vitamin the body needs still isn’t clear, but the researchers found the lowest death rates associated with 50 nmol of vitamin per liter of blood serum.
Less than 10 nanomol (nmol) per liter and more than 140 nmol of vitamin D per liter of serum were both found to be associated with higher chance of dying.
"We have moved into a controversial area that stirs up strong feelings just like debates on global warming and research on nutrition. But our results are based on a quarter of a million blood tests and provide an interesting starting point for further research”, Durup said in a media release.
The study doesn’t confirm that higher levels of vitamin D are harmful to health, but it does suggest more research is needed to understand why people with too much of the vitamin had higher mortality rates. It may be that too much vitamin D is a health risk, pending more studies.