Debate of the Week: Vitamin D

Our experts comment on the recent IOM report: Dietary Reference Intakes for Calcium and Vitamin D

“The recent IOM report ["Dietary Reference Intakes for Calcium and Vitamin D"] points to the considerable amount of information we have yet to learn about vitamin D and health. Numerous studies point to strong associations between low vitamin D serum levels and many unfavorable health outcomes-but associations do not prove causality. The IOM report was framed by the inability to point to a substantial body of data demonstrating that high-dose vitamin D supplements reduce the burden of any disease and the risk that a recommendation of higher-dose vitamin D supplementation for large populations of normal individuals has risk of doing harm. Given these data, the IOM made cautious recommendations and affirmed that continued research regarding the safety and efficiency of higher dose supplementation is necessary. In my view, patients with cancer under care of a physician should have their 25 [OH] vitamin D3 level measured and take enough supplemental vitamin D3 to raise the serum concentration into the normal range [32 ng/ml - 100 ng/ml].”

-Donald L. Trump, MD
Director, Roswell Park Cancer Institute

“The IOM report put much emphasis on bone health. However, vitamin D receptors are present in many other tissues in the body. The role of vitamin D in other health conditions has not been adequately studied. Several prospective clinical trials testing the role of vitamin D in the setting of cancer prevention or cancer treatment are underway or have recently completed. We should expect more data soon to help us get a clear picture of what to do in cancer patients.”

-Gary Deng, MD, PhD
Associate Member/Attending Physician
Integrative Medicine Service
Memorial Sloan-Kettering Cancer Center

“The recent Institute of Medicine (IOM) news release cautioning against vitamin D supplementation for most people brings into question a number of small but compelling investigations linking vitamin D levels to various levels of cancer risk.  As with many studies in cancer prevention, large populations, longitudinal follow-up of those patients, and control for multiple intervening variables is required to determine risk or benefit.  Many hypotheses in cancer prevention trials have been disproven with time: What we do know is that cells of the brain, immune cells, prostate, colon and breast have vitamin D receptors and that the active form of vitamin D (1,25-dihydroxyvitamin D) plays a role in proliferation, differentiation, apoptosis, and angiogenesis.  There are a number of studies that continue to evaluate the role of vitamin D in cancer prevention.

"As with most nutrients, adequate vitamin D is best obtained in a balanced diet. Unique to adequate vitamin D levels is a healthy amount of sun exposure.  Factors that place a patient at risk for vitamin D deficiency include reduced skin synthesis (more common in patients with skin GVHD, darker pigment, and northern latitudes), malabsorption syndromes, HAART treatment for AIDS, liver failure and nephrotic syndrome.  Mega-doses of any oral supplement are not generally recommended.  Standard doses of vitamin D are considered safe and reports of toxic vitamin D levels with standard doses are very rare.  We will need to wait for the results of longitudinal prevention trials to determine the true risk or benefit of vitamin D deficiency or supplementation.^1-4”

-Sandra E. Kurtin, RN, MS, AOCN, ANP-C
Hematology/Oncology Nurse Practitioner
Arizona Cancer Center

Related Content:Colorectal Cancer Patients with Vitamin D Deficiency See Worse OutcomesONCOLOGY Nurse Edition: Vitamin DIntegrative Oncology: Vitamin DWithout Randomized Trials, Role of Vitamin D in Cancer Prevention Remains UncertainBone Complications of Cancer Treatment in the Elderly

References:
1. Holick, M. N Engl J Med, 2007;357:266-281
2. Overcash J. Clin J Oncol Nurs. 2008;12(4):655-662
3. Lim et al. Int J Cancer. 2009;124:979-986
4. Kellof et al. NCI, DCPC Clinical Development Plan: Vitamin D and Analogs. 2009;269-281.