Washington, D.C.—After reviewing the current research behind the health benefits of vitamin D and calcium, the Institute of Medicine (IOM) has issued a report that updates dietary reference intakes (DRIs) for these nutrients. The DRIs recommend for the first time both an estimated average requirement and a recommended dietary allowance (RDA) for calcium and vitamin D; previously just adequate intakes (AIs) were used.

For years, vitamin D proponents have advocated upping the DRIs because of the vitamin’s value for immune health, diabetes support, cancer prevention and more. But, the results of the report “may be surprising to some,” stated A. Catharine Ross, chair of the Committee to Review Dietary Reference Intakes for Vitamin D and Calcium and professor of nutrition at Pennsylvania State University. First, she noted that while the committee felt there was strong evidence for vitamin D’s value to bone health, adequate cause and effect data are missing for the other “newer” applications for vitamin D. Thus, the group stated that there is no solid, conclusive evidence showing vitamin D would prevent such diseases. Nonetheless, Ross advocated for further research into these topics, noting that some established evidence is positive for the use of vitamin D for cancer prevention (though other data show no benefit).

Thus the group suggested creating an RDA of 600 IUs for those ages one through 70 (including pregnant and lactating women) and 800 IUs for those over 71. The previous AIs for those under 50 were 200 IUs; 400 IUs for those 51–70; and 600 IUs for those 71 and older, though it should be mentioned that judging RDAs against AIs is like comparing apples and pears. These recommendations are based on minimal sun exposure, since the risks of UV exposure from sunlight (needed for natural vitamin D synthesis) made the group hesitant to recommend spending much time in the sun unprotected, Ross stated.

Not everyone is in agreement with the change. Dallas Clouatre, Ph.D., of Jarrow Formulas notes that IOM came to its conclusion of 600 IUs of vitamin D daily “by positing as a healthy baseline for serum vitamin D a level that apparently is not endorsed by any major figure directly involved in vitamin D research.” The IOM states that 50 nmol/L is ideal, but Clouatre points out that a 75 nmol/L serum level is more appropriate. “As I pointed out in a review article published in 2009 [Am. J. Clin. Nutr.], one recent study argues that the amount of vitamin D needed to maintain the desired serum 25-hydroxyvitamin D concentration may run between 3,800 and 5,000 IU per day, amounts in excess of the currently officially endorsed upper limit of intake.  These amounts are based on the researchers’ estimate of the intake of vitamin D3 needed to raise serum 25(OH)D to equal to or greater than 75 nmol/L and is in line with long-time recommendations of many experts of 3,000 to 5,000 IU/day. (Am. J. Clin. Nutr. 77[1], 204–210 [2003]).”  When you figure in the sun, many researchers feel that “a reasonable level of intake to prevent seasonal fluctuations is approximately 1,600 IU/day (Am. J. Clin. Nutr. 88 [6], 1535–1542 [2008])” says Clouatre.  

Darrell Rogers, communications director for the Alliance for Natural Health-USA agrees that the new vitamin D recommendations “are absurdly low and fly in the face of scientific evidence. “ He makes the point that “Their new recommendation is the bare minimum required to prevent bone disease, based on the lowest common denominator.  But they failed to look at healthy populations to determine what vitamin D levels and RDAs should be for optimum health, not only for bone, but for overall quality of life.”

Of note, the IOM upped the recommended upper limit from 2,000 IUs to 4,000 for anyone older than nine. Ross noted that this is a “conservative estimate” that took into account the relationship between high doses of vitamin D and all-cause mortality, bone breaks from falls and other factors. But again, many feel 4,000 IUs is too low. States Rogers, “The IOM stated multiple times throughout the report that they had very little data [from harm-based studies] and stated they needed additional data before firm conclusions could be made. Nevertheless, they noted that in the absence of a benefit at higher levels, the cautious approach was deemed justified. Of course, they skewed the evidence so that only a very few random controlled trials were taken into consideration in determining benefit, and they considered all evidence available to look for any detriment. 10,000 IUs was found to be their upper limit but was ‘adjusted down’ to 4,000 without explanation.”

The 10,000 IUs figure is one suggested by vitamin D/calcium researcher Robert Heaney of Creighton University, and one with which many researchers agree. “Given that our natural vitamin D production in response to sunlight is routinely on the order of 10,000 IU per day and given, likewise, the paucity of evidence of toxicity until one approaches levels of ingestion three times that amount, I would argue that a tolerable upper limit (UL) of intake should be in the range of 10,000 IU,” states Clouatre, who also states that Heaney’s comments were inexplicably rejected by the committee. In addition, none of the commented from the experts were made available to the public.

Adds Rogers, “The IOM has done a huge disservice to the millions of people who are vitamin D deficient and need higher levels to get and stay healthy…The Vitamin D Council and Harvard Department of Nutrition have been critical of the report and suggest vitamin intake levels beyond the IOM recommended amounts.”

As for calcium, the group felt that teen girls are the only group at risk of getting too little calcium, while older women may be taking too much. The RDAs for calcium are 200 mg for infants under six months; 260 mg for infants six to 12 months; 700 mg for children ages one through three; 1,000 mg for children ages four through eight; 1,300 for anyone ages nine through 18; 1,000 mg for males ages 19–70; 1,200 mg for males older than 70; 1,000 mg for women ages 19–50; and 1,200 mg for women older than 51.

Published in WholeFoods Magazine, January 2011 (online 11/30/2010, updated 12/6/2010)