Too Much Vitamin D May Increase Your Mortality Risk

Vitamin D is essential to your health. Not only does it help calcium reach your bones, but it also helps fight against certain cancers. However, too much vitamin D has its drawbacks. According to a study published in the Journal of Clinical Endocrinology and Metabolism, people who have too much of the vitamin may increase their mortality risk. 

Researchers from the University of Copenhagen took blood samples from 247,574 Copenhageners from the Copenhagen General Practitioners Laboratory. Upon analysis of the samples, they realized that blood with less than 10 nanomol (nmol) of vitamin per liter of serum raised the participants’ mortality risk by 2.31 times. On the other hand, blood with more than 140 nmol of vitamin per liter of serum pushed mortality risk up by 1.42. These numbers were compared to blood samples containing 50 nmol of vitamin per liter of serum, which pose the lowest health risk. 

Darshana Durup, a PhD student and a co-author of the study, says that the results were unexpected. "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."

At this point, it’s hard to say exactly what makes too much vitamin D harmful to your health. Durup explains, "Our data material covers a wide age range. The people who participated had approached their own general practitioners for a variety of reasons and had had the vitamin D level in their bloodstream measured in that context. This means that while the study can show a possible association between mortality and a high level of vitamin D, we cannot as yet explain the higher risk."

Still, too much of anything is hardly ever a good thing. If you’re interested in increasing or decreasing your vitamin D intake, it’s better to consult your doctor.


(Photo by Laura B. Dahl via Flickr Creative Commons)