It has come to our attention that there was an error in the Hotline distributed on 12/6/10. The heading for the third section under Summary of IOM Recommendations should read:

Serum 25 hydroxyvitamin D levels

The corrected Hotline appears below. The Hotline editors regret the error.

Dietary Reference Intakes for Calcium and Vitamin D: Report from the IOM

December 6, 2010

The Institute of Medicine released its guidelines for calcium and vitamin D intake on November 30, 2010. The report was commissioned by the U.S. and Canadian governments in response to "conflicting messages" to the public about the optimum intake of calcium and, especially, vitamin D needed to promote bone health and other health outcomes while minimizing risk. The controversy was stimulated by a number of factors:

• Observational studies reporting an association between higher vitamin D levels and multiple beneficial health outcomes in autoimmune disease, cancer, infection, and heart disease that led some experts to suggest public health measures to increase vitamin D intake in the general population.
• An increase in the lower limit of normal for serum levels of 25 hydroxyvitamin D to >31 ng/ml by many reference laboratories, leading to a dramatic increase in the diagnosis of Vitamin D deficiency in the US population
• Media attention and public interest.
• Increasing concern about the risks of augmenting calcium absorption, including kidney stones and possible cardiovascular risks¹.

The IOM report was based on a review of almost 1000 studies and two comprehensive, independent meta-analyses.^2,3

Summary of the IOM Recommendations

Vitamin D:

• RDA
  • 800 IU/d for women over the age of 71
  • 600 IU/d for women in other age groups, men, and children
  • 400 IU/d for infants under 12 months

Calcium:

• RDA
  • 1200 mg/d for adult women over the age of 50 yrs and men 71 years and older
  • 1000 mg/d for younger adult women (who are not breastfeeding or lactating) and adult men.
• "National surveys in both the United States and Canada indicate that most people receive enough calcium, with the exception of girls ages 9–18, who often do not take in enough calcium. In contrast, postmenopausal women taking supplements may be getting too much calcium, thereby increasing their risk for kidney stones." (IOM report)
• Recommendations for vitamin D and calcium reflect total daily intake, including both dietary sources and supplements.

Serum 25 hydroxyvitamin D levels:

• The IOM committee recommended a serum level of at least 20 ng/ml to promote bone health "for practically all individuals" which differs from the cutoff of 31 ng/ml currently used by most reference laboratories. The report goes on to state, "… the mea¬surements, or cut-points, of sufficiency and defi-ciency used by laboratories to report results have not been set based on rigorous scientific studies, and no central authority has determined which cut-points to use." and that the current cutoffs are "much higher than the committee suggests is appropriate."

Toxicity:

• The IOM states that the recommendations for safe "upper level intakes" for calcium and vitamin D should not be used as a goal of therapy. When intake of vitamin D and calcium exceeds 4,000 IUs/d and 2,000 mg/d, respectively, the risk for toxicity increases.
• People with renal insufficiency are more susceptible to toxicity.

Limitations Cited in the IOM Report

• The lack of data about optimal serum Vitamin D levels and the risks and benefits of calcium and vitamin D intake in diverse ethnic groups, especially African Americans, who have higher bone density despite lower vitamin D levels.
• The difficulty separating the effects of calcium and vitamin D because most clinical trials used both agents at varying doses.
• Lack of data about the interaction between vitamin D intake and sun exposure.
• Limited data about the long term effects of calcium and vitamin D intake and health outcomes (both benefits and risks).
• The need to recommend safe "upper limits" of intake to ensure public health despite limited data.

Bottom Line

• "Overall, the committee concludes that the majority of Americans and Canadians are receiving adequate amounts of both calcium and vitamin D. Further, there is emerging evidence that too much of these nutrients may be harmful." (IOM report)
• Although adequate calcium and vitamin D intake is important for bone health, there is inadequate evidence to support claims of benefit in other health conditions.
• The IOM report does not suggest regular monitoring of 25 hydroxyvitamin D levels in the general population but does advocate monitoring for those at risk, such as institutionalized elderly who have a greater risk of deficiency but are also more susceptible to toxicity from excess intakes of both calcium and vitamin D.
• These recommendations are for the general population. Those with chronic conditions and disorders that impact bone metabolism should consult their physicians

Footnotes

1. Bolland MJ. Vascular events in healthy older women receiving calcium supplementation: randomized controlled trial.BMJ. 2008;336(7638):262-6.
2. Cranney, A. et al. AHRQ-Ottawa Evidence-Based Report on Effectiveness and Safety of Vitamin D in Relation to Bone Health. Am J Clin Nutr 2008;88:513S-519S
3. Pittas AG, et al. Systematic review: Vitamin D and cardiometabolic outcomes. Ann Intern Med. 2010;152(5):307-14.

Resource: IOM Report: Dietary Reference Intakes for Calcium and Vitamin D (http://www.iom.edu/Reports/2010/Dietary-Reference-Intakes-for-Calcium-and-Vitamin-D.aspx)

Hotline Author: Lenore Buckley, MD, MPH, Professor of Internal Medicine & Pediatrics, VCU School of Medicine
Hotline Editors: Arthur Kavanaugh, MD, and Eric Ruderman, MD.
Disclosures: Drs. Buckley, Kavanaugh and Ruderman have no conflict of interest regarding the material in this ACR Hotline.

In addition to review by the editors, this Hotline has been reviewed by all members of the ACR Executive Committee and the Communications and Marketing Committee.

The ACR Hotline is provided by the ACR Communications and Marketing Committee as a service to members. This Hotline reflects the views of the author(s) and does not represent a position statement of the American College of Rheumatology.

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