Some consumers go overboard with taking vitamin D supplements, study finds

Vitamin supplements have exploded in popularity since the turn of the century, with many consumers relying on them to deliver essential nutrients that aren’t covered by their diets. But a recent study suggests that some consumers are going overboard when it comes to taking vitamin D supplements.

In their report, researchers working with the Journal of the American Medical Association (JAMA) Network detail how many consumers who take vitamin D supplements exceed the daily upper limit suggested on their packaging. This is dangerous, they say, because getting too much vitamin D can result in soft tissue and abnormally high levels of calcium in the blood, which can lead to vascular calcification and cardiovascular problems.

“Characterizing trends in vitamin D supplementation, particularly at doses above the tolerable upper limit, has important and complex public health and clinical implications,” the authors said.

Pushing the limits

The current recommended dietary allowance for vitamin D is 600 IU per day for adults aged 70 or younger and 800 IU per day for those over the age of 70. To see how closely consumers followed these limits, the researchers analyzed nearly 40,000 participants to see how many consumed over 1,000 IU per day.

They found that the number of participants who went over the 1,000 IU per day limit was 18.2% in 2013-2014, up sharply from the 0.3% that did the same in 1999-2000. Pushing further, they found that 3.2% of participants consumed more than 4,000 IU per day in supplemental intake, which researchers say is the highest tolerable limit that can be taken.

The findings showed that women were more likely than men to take over 4,000 IU or more daily, while non-Hispanic white individuals led all other races. Those over the age of 70 were more likely than their younger counterparts to do the same.

The full study has been published in JAMA.