14 June 2011

Updated clinical vitamin D guidelines

Michael Holick, MD, Ph.D., told me in a phone interview nearly a year ago that vitamin D insufficiency and deficiency was "one of the most common medical conditions" and has implications on the health of bones, the heart, the immune system, and likely every cell in the body.

Dr. Holick added, "If a normal adult isn’t taking at least 1,500 to 2,000 IU from supplement and diet—and you can’t really get it from your diet—then we know you’re vitamin D deficient."

Now, The Endocrine Society has released new clinical practice guidelines intended to help curtail widespread vitamin D deficiency with extra focus on care for populations who are most at risk.

The guidelines follow on the coattails of last November's updated vitamin D recommendations by the Institute of Medicine (IOM), which several experts have condemned as conservative and inadequate. In response, a "Task Force," led by Dr. Holick, reexamined the evidence and compiled new recommendations to provide a more therapeutic emphasis.

The guidelines call for screening populations at risk for vitamin D deficiency and correcting deficiencies with supplementation at levels high enough to maximize effects on calcium, bone and muscle metabolism.

The Task Force recommends maintaining blood concentrations of 25(OH)2D (the active circulating form of vitamin D) consistently above 30 ng/mL. Circulating blood levels below 30 ng/mL are regarded as "insufficient" and below 20 ng/mL as "deficient".

To assist at-risk individuals with meeting blood levels above 30 ng/mL of circulating vitamin D, the Task Force issued new dietary intake recommendations that differ significantly from those given by the IOM:
  • Infants ages 0-1: 400-1,000 IU/day
  • Children ages 1-18: 600-1,000 IU/day
  • Adults ages 18+: 1,500-2,000 IU/day
  • Pregnant or nursing women under 18: 600-1,000 IU/day
  • Pregnant or nursing women 18+: 1,500-2,000 IU/day
  • Obese children and adults: at least 2-3 times the recommendation for their age group
  • Children and adults on anticonvulsants, antifungals and AIDS medications: at least 2-3 times the recommendation for their age group
The Task Force also increased Tolerable Upper Limits for vitamin D to substantially higher levels than what the IOM recommended last fall.

In addition, they recommend higher dosages of vitamin D as clinical strategies for patients with vitamin D deficiency, malabsorbtion syndromes, and patients on medications that may affect vitamin D metabolism. Patients with these conditions should work with their personal physicians to determine what dosage is right for them.

Acknowledging a gap in the clinical evidence, the Task Force suggested that more trials with higher intakes of vitamin D are "desperately needed" to more properly understand the potential health outcomes.

During an online news conference, Dr. Holick asserted that 30ng/mL should only be regarded as a minimum for maintaining a healthy body. The ideal range for circulating blood levels of vitamin D in both children and adults, he said, should be between 40 to 60 ng/mL.

Source: Holick MF et al. Evaluation, Treatment, and Prevention of Vitamin D Deficiency: and Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab 2011; 96: 0000-0000. doi:10.1210/jc.2011-0385

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