A national study performed by researchers at the University of Minnesota found that nearly one in five US adults are taking supplemental vitamin D, and a growing number are taking excessively high doses. 

Karen Hansen, MD, MS, associate professor, Rheumatology, provided her perspective about the issue in coverage by Reuters. 

While the recommended daily intake of vitamin D for most adults is 600 IU or 800 IU after age 70, the survey of over 39,000 adults from 1999 to 2014 found that 18 percent of adults were taking more than 1,000 IU per day in 2013-14, and 3.2 percent were taking more than 4,000 IU per day. 

At these excessively high levels, physicians are concerned about increased risk of fractures, falls, kidney stones, and some cancers. When it comes to vitamin D, says Dr. Hansen, “Too much is not always better." 

Resources:

• "Many Americans taking too much vitamin D," Reuters, June 20, 2017