The psychology of taking vitamin and mineral supplements for most people is that “if some is good, more is better.” This thinking however, at least when it comes to taking vitamin D supplements, is not only incorrect, it could even be dangerous, especially for the elderly.
Pamela L. Lutsey, PhD, MPH, and her colleagues from the University of Minnesota in Minneapolis, surveyed data from the nationally representative National Health and Nutrition Examination Survey (NHANES), related to vitamin D intake of doses between 1,000 and 4,000 IU or more from 1999 until 2014.
The report was published in JAMA in June 2017, and showed an increase in the number of people taking doses of vitamin D over the daily upper limit set by the FDA. The report said that at least 3% of the population took more than the upper limit of the vitamin.
In 2011 a study was published that showed vitamin was good for bone health, but also said there was a possibility of too much vitamin D causing harm. The chances of higher than normal levels of calcium in the blood and soft tissue calcification increased with higher doses of vitamin D in the 4,000 IU daily ranges.
The dose which is recommended for adults under 70 is 600 IU/day and 800 IU/day for those over age 70.
The survey looked at the vitamin D intake of 39,243 participants. Of these, 18.2% took 1,000 IU/day or more in 2013-2014, while in 1999-2000 only 0.3% took such high doses on a daily basis.
The study also found that 3.2% of the participants took levels above 4,000 IU/day in 2013-2014, while in 2005-2006 less than 0.1% took such high amounts of vitamin D. The increase in intake was found across most age groups, ethnicities and gender.
“Characterizing trends in vitamin D supplementation, particularly at doses above the tolerable upper limit, has important and complex public health and clinical implications,” said the authors.
Take away: Too much of a good thing could be harmful.
