So much for spring fever! Scientists say high vitamin D levels could be dangerous for your health

By Kylie Gilbert
March 10, 2015
Corbis Images

We know that vitamin D deficiency is a serious issue. After all, one study shows that on average, 42 percent of Americans suffer from a vitamin D deficiency, which can lead to an increased risk of death from issues like cancer and heart disease, and a whole host of other weird health risks. However, the opposite-too little D-could be just as dangerous, according to a new University of Copengahen study that found, for the first time, a correlation between high levels of vitamin D and cardiovascular deaths. (Of course correlation doesn't equal causation, but the results are still surprising!)

The scientists studied the level of vitamin D in 247,574 people and analyzed their mortality rate over a seven-year period after taking the initial blood sample. "We have looked at what caused the death of patients, and when numbers are above 100 [nanomoles per litre (nmol/L)], it appears that there is an increased risk of dying from a stroke or a coronary," study author Peter Schwarz, M.D. said in the press release.

As with most things in life, when it comes to vitamin D levels, it's all about finding a happy medium. "Levels should be somewhere in between 50 and 100 nmol/L, and our study indicates that 70 is the most preferable level," Schwarz says. (The National Institutes of Health comes in much lower with their number, stating that 50 nmol/L covers the needs of 97.5 percent of the population, and 125 nmol/L is a "dangerously high" level.)

So what does it all mean? Well, since vitamin D levels depend on many factors such as skin color and weight, it's hard to know without getting a blood test. Once you know whether you're getting too much or too little, you'll be able to choose an IU dose that's right for you. (Here, more info from the vitamin D council on how to decipher your blood results). Until you find out your levels, avoid taking more than 1,000 IU per day and beware of signs of vitamin D toxicity, like nausea and weakness, Tod Cooperman, M.D. president of independent testing company, told us back in December. (And read up on more information about How to Pick the Best Vitamin D Supplement!)