New Institute of Medicine Recommendations on Vitamin D

Evidence is lacking for extraskeletal health benefits of vitamin D; most people in the U.S. and Canada have adequate serum 25-hydroxyvitamin D levels.

Vitamin D is essential to human health. The main sources of this fat-soluble vitamin are dietary intake from foods and supplements, and cutaneous sun exposure. Despite vitamin D's importance, its normal levels, recommended daily allowance, and the spectrum of its health effects have been shrouded in controversy. Therefore, the U.S. and Canadian governments requested that the Institute of Medicine analyze existing information about vitamin D and update its viewpoints accordingly. A committee of 14 scientists reviewed more than 1000 studies and evaluated the opinions of experts in the field to prepare their report.

The committee concluded that vitamin D and calcium play critical beneficial roles in bone metabolism, but evidence is insufficient for health benefits of vitamin D in extraskeletal contexts (e.g., promotion of immune response; protection against cancer, cardiovascular disease, diabetes, and preeclampsia). Serum 25-hydroxyvitamin D levels of 20 ng/mL are sufficient to maintain adequate bone health, and dietary intake of 600 IU daily is enough to achieve adequate vitamin D stores in most individuals younger than 71; for those who are 71 and older, 800 IU daily is recommended. Although the mean intake of vitamin D in North American populations is less than this, the committee found that mean blood levels are ≥20 ng/mL, suggesting that the amounts of sun exposure received are sufficient to maintain adequate vitamin D levels. The committee cautioned against taking large doses of vitamin D (i.e., >4000 IU daily) because at such doses, harmful effects (e.g., renal and tissue damage) emerge.

Comment

The Institute of Medicine is an independent organization of medical leaders that provides objective and authoritative guidance. This thorough and comprehensive report by a committee of esteemed scientists provides important information for clinicians about vitamin D. First, evidence is lacking for health benefits of vitamin D beyond its effects on bones. Second, most people in the U.S. and Canada already have adequate vitamin D levels, so excessive outdoor activity or use of tanning beds to supplement those levels is unnecessary.

Reviewing Author

Craig A. Elmets, MD

Disclosures

Consultant / Advisory board Astellas Pharmaceuticals

EquityVaxin

Grant / Research support NIH; NIH/NCI; Veteran’s Administration; Ferndale Laboratories; Kyowa Hakko Kirin Pharma, Inc.

Editorial boards Cancer Prevention Research; Photodermatology, Photoimmunology, & Photomedicine; UpToDate; eMedicine; Journal of Dermatological Sciences; JAMA Dermatology

Leadership positions in professional societies American Academy of Dermatology (Vice Chair, Committee on Science and Research); Photomedicine Society (Board of Directors)