Looks like consumers can load up on vitamin D without worrying about adverse health effects, the Council for Responsible Nutrition reported Thursday. According to Andrew Shao, PhD, the CRN’s senior vice president of scientific and regulatory affairs, the high amount of vitamin D needed to score strong bones and lower disease risk is not enough to put people in danger of hypercalcemia, a condition characterized by dangerously high blood-calcium levels.
While ample research has emerged in recent years touting vitamin D’s health benefits and suggesting the current dietary reference intake be boosted, it remained uncertain whether the pluses of high D doses outweighed the potential minuses.
To determine safety, Shao and his team analyzed results from a number of trials to compare the benefits of vitamin D supplementation (as determined by falls, fractures, cardiovascular issues and colon cancer ) directly to risks that stemmed from high blood calcium.
“We found that risk for hypercalcemia doesn’t generally happen in normal adults until vitamin D intake is really high, as in tens of thousands of IUs, or even more,” Shao said. The researchers hope these findings, published in the July issue of Osteoporosis International, will influence the Institute of Medicine to increase the DRI, currently under review and set to be announced in November.
“In 1997, when the IOM set the DRI at 400 to 600 IU and the tolerable upper intake level at 2,000 IU, they didn’t have a lot of data to go on—they relied largely on one poorly done study,” Shao said.
Shao recommends shooting for 1,000 to 1,200 IU per day year-round. And since people tend to soak up more D from the sun in the summertime, they should be especially sure to take in enough of the vitamin in the winter via food and supplements. Food sources include fortified milk, fortified cereal and fatty fish like salmon—but definitely don’t rely on diet, Shao said. “Milk offers only 40 or 50 IU per serving, so even if you drink milk and eat fish on a regular basis, you’re probably only getting about 400 IU per day—the low end of what’s adequate.”
Multivitamins offer about 400 IU, and bone-health formulas or standalone vitamin D supplements, often in the D3 form, can make up the rest to help bring total intake to the 1,000-1,200 range, Shao explained.
Luckily, since vitamin D research has saturated the media and its benefits have become well known, retailers likely don’t have to work overly hard to push sales of the supplement. Shao suggests stocking a variety of affordable vitamin D options—multis, bone formulas, standalones—and keeping them visible. Also, make sure employees can explain to customers the notion of adding up IUs from various sources to hit the overall target and that they needn’t worry about overdoing the D.