IOM Report Says D, Calcium Supplements Not Necessary

WASHINGTONAn expert committee compiled by the Institute of Medicine (IOM) to investigate dietary reference intakes (DRIs) of calcium and vitamin D has concluded intakes are mostly adequate and supplementation is largely unnecessary. The panel also challenged advocates of such supplementation to prove it is safe.

Directed by the U.S. and Canadian government to assess the current data on the two nutrients and update any recommendations, IOM told the committee to ensure its review considered indicators for chronic disease risk reduction as well as other health outcomes. The review was to be conducted as a risk assessment, incorporating systematic evidence-based reviews of the literature, when appropriate. In the end, they were asked to update DRIs, as appropriate, using a risk assessment approach that includes:

The committees report, Dietary Reference Intakes for Calcium and Vitamin D, stated most Americans under the age of 70 need no more than 600 IU/day of vitamin D, while those over 70 may need as much as 800 IU/day. Calcium needs range from 700 mg to 1,300 mg daily, depending on age, claimed the report, which utilized more than 1,000 studies as well as input from scientists and stakeholders.

The committee considered not just bone health implications from vitamin D, but also protection against cancer, heart disease, autoimmune diseases, and diabetes. The panel concluded despite the potential benefits shown in these studies, these results are generally mixed and conflicting, providing no concrete evidence vitamin D conveys any such benefits.

"There is abundant science to confidently state how much vitamin D and calcium people need," said committee chair Catharine Ross, professor and Dorothy Foehr Huck Chair, department of nutritional sciences, Pennsylvania State University, University Park.  "We scrutinized the evidence, looking for indications of beneficial effects at all levels of intake.  Amounts higher than those specified in this report are not necessary to maintain bone health." 

The panel did concede some adolescent girls may not be taking in enough calcium, and the elderly might be under optimal intakes of both calcium and vitamin D, but they should increase their intake of foods rich in these nutrients and possibly take supplements.

The committee argued recently advanced tests for blood levels of these nutrients have led to much confusion, as the cut-off points for sufficient-versus-deficient status are not based on rigorous scientific studies and are not standardized. This could skew test results and inaccurately increase the number of deficient populations, they said. They claimed available data shows almost all individuals get sufficient vitamin D when their blood levels are at or above 20 ng/mL in America, or 50 nmol/L in Canada. 

To account for those who get minimal sunlight year-round, the committee set its baseline for sun-based vitamin D intake at the level that provides such people a sufficient blood level of the vitamin, basing its DRI recommendation on this minimum.

On the other hand, the committee reported too much calcium, a problem they l inked partly to the increased fortification of foods and beverages, can cause kidneys tones, while excess vitamin D can harm the kidneys and the heart. While the evidence of such adverse effects were from studies on short-term, high-dose intakes, they said there is some signals suggesting long-term, high-dose intake of vitamin D is associated with greater risks of death and chronic disease, a potential that is reflected in the committees recommendations for intakes people should not exceed.

J. Christopher Gallagher, M.D., director of the bone metabolism unit at the Creighton University School of Medicine in Omaha, Neb., told the NY Times, The onus is on the people who propose extra calcium and vitamin D to show it is safe before they push it on people.

"While it is too early to make definitive statements about the risks associated with routine high doses of vitamin D and calcium, people don't need more than the amounts established in this report," Ross said.  "Past cases such as hormone replacement therapy and high doses of beta carotene remind us that some therapies that seemed to show promise for treating or preventing health problems ultimately did not work out and even caused harm.  This is why it is appropriate to approach emerging evidence about an intervention cautiously, but with an open mind."

The Council for Responsible Nutrition (CRN) called the report 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. They said the committees modest increase of vitamin D DRI in the form of estimated average requirements (EARs) for adults and its doubling the tolerable upper intake level (UL) from 2,000 to 4,000 IU/day for adults represent the first update to nutritional reference values established in 1997.

However, this update still lags behind the mountain of research demonstrating a need for vitamin D intake at levels possibly as high as 2,000 IU/day for adults, according to Andrew Shao, senior vice president, scientific and regulatory affairs at CRN, who said CRN recognizes the challenges the committee faced in its review and recommendations, and added the recommendations on calcium are in line with what CRN expected, based on the current body of science on the mineral.

 On the other hand, he said due to the mountains of research showing numerous benefits from higher intakes of vitamin D, the greater scientific, regulatory and medical communities were awaiting this report, it is much more conservative and cautious than anticipated. 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 weve been anxious for the IOM to catch up, he said.

CRN further noted NHANES results showed widespread vitamin D deficiencies, and science has consistently linked such deficiency to increased risk for certain cancers, cardiovascular disease, osteoporosis, diabetes, and other health-related issues; high intakes of vitamin D can help reduce these risks.

In fact, CRN and other scientists have demonstrate as much as 10,000IU/day vitamin D is a more optimal UL, as shown in their paper published in Osteoporosis International (2010 Jul; 21(7):1121-32).

The IOM' Committee report can be viewed at the IOM Website .