IOM Conservatively Raises DRI for Vitamin D

November 30, 2010

The Institute of Medicine's newly recommended vitamin D levels are still lower than many industry members had hoped for.

The Institute of Medicine (IOM) today released updated dietary reference intakes (DRIs) for vitamin D and calcium, last reviewed in 1997. Recommended vitamin D levels are still lower than many industry members had hoped for.

Overall, the committee concluded that the majority of Americans and Canadians are receiving adequate amounts of both calcium and vitamin D.

For vitamin D, the new recommendations set an Estimated Average Requirement (EAR) of 400 IU/day for adults and a Recommended Dietary Allowance (RDA) of 600 IU/day for adults (and 800 IU/day for adults 71 and older).

The report also capped the Tolerable Upper Intake Level (UL) at 4000 IU/day. This number is double the 2000 IU/day previously recommended, but the Council for Responsible Nutrition (CRN; Washington, DC) and many industry members had been calling for a UL of 10,000 IU/day.

As for calcium, the changes were also modest and reflect slight adjustments for infants, children, and the elderly. Based on age, new RDA recommendations ranged from 700 to 1300 mg/day. (DRI-comprising EAR, RDA, and UL values-serve as a basis for, among other things, setting standards for food and dietary supplement labeling.)

CRN stated that the increased EARs and RDAs for vitamin D are lower than many in the industry would have liked to see. The association did note, however, that government recommendations on the whole tend to be more conservative.

“While an increase in the recommendations for vitamin D will benefit the public overall, such a conservative increase for the nutrient lags behind the mountain of research demonstrating a need for vitamin D intake levels possibly as high as 2000 IU/day for adults,” stated Andrew Shao, PhD, CRN’s senior vice president of scientific and regulatory affairs. “However, CRN recognizes the challenges associated with the DRI process and the difficulty in making broad-based recommendations for an entire population.”

One of those challenges is taking into account the level of vitamin D that people obtain naturally from sunlight, to which exposure can vary greatly between people, stated representatives from the IOM committee in a press conference today.

To make its recommendations, the IOM committee assessed more than 1000 studies and reports on the latest calcium and vitamin D science, considering studies covering these nutrients’ effects on conditions such as cancer, cardiovascular disease and hypertension, diabetes and metabolic syndrome, immune response, falls, physical performance, preeclampsia, and reproductive outcomes.

While the committee did not draw conclusions on the effects of vitamin D and calcium on the above conditions, it did confirm that a “strong body of evidence from rigorous testing substantiates the importance of vitamin D and calcium in promoting bone growth and maintenance.”

From Diet or Supplements
IOM said that it is up to consumers whether they meet the DRIs through diet or dietary supplements.

"The recommendations are for total intake, so that would be intake from diet and supplements,” stated IOM committee chair Catharine Ross, PhD, at the press conference. “We think that many individuals will be able to obtain these recommended dietary allowances from diet, but for those who can't, we're not really specifying the source. A supplement may be appropriate for some age groups, so that may be a supplement of calcium, for example, for older women; it may be a supplement of vitamin D. But it is important to convey clearly that the recommendations are not for a supplement or just for diet; it's for the combination, however one obtains the vitamin D or the calcium."

A Modest Step
CRN called the IOM committee’s recommendations “a modest step in the right direction that fell short of truly capturing the extensive and positive research that has consistently supported the need for people to significantly raise their vitamin D levels.”

However, CRN did note that this is the first time EARs have been set for both calcium and vitamin D; previously, the IOM committee believed there was not enough conclusive science to set EARs and had only established Adequate Intake levels (AIs).

Room for Increase?
Over the past decade, growing research has demonstrated more benefits for vitamin D at levels higher than IOM’s current recommendations, added Shao.

“The research for vitamin D has been so positive that the medical community and consumers already have a heightened awareness of the value of this nutrient, and we’ve been anxious for the IOM to catch up,” he said.

Twenty-seven percent of supplement users now take a vitamin D supplement, based on CRN’s most recent annual consumer survey on dietary supplement usage, released this past September. The 27% is an increase from the 19% and 16% of supplement users who indicated they took vitamin D supplements in 2009 and 2008, respectively.



Read IOM’s statement here.

Read CRN’s response here.