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To Your Health: NLM update Transcript

Vitamin D's limitations: 05/04/2015

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Greetings from the National Library of Medicine and MedlinePlus.gov

Regards to all our listeners!

I’m Rob Logan, Ph.D., senior staff, U.S. National Library of Medicine.

Here is what’s new this week in MedlinePlus.

It may be premature to take vitamin D supplements to prevent illnesses and diseases with the exception of keeping bones healthy, finds an insightful viewpoint recently published in Journal of the American Medical Association.

The viewpoint’s two authors, who are from Harvard Medical School, report the U.S. Preventive Services Task Force and the Institute of Medicine (IOM) both recently concluded the evidence that vitamin D supplements boost skeletal (bone) health does not extend to preventing some other adverse health outcomes.

The viewpoint’s authors note vitamin D has been perceived as possibly associated with the prevention of cancer, cardiovascular disease, diabetes, autoimmune disorders, cognitive decline, as well as other conditions.

Primarily for these reasons, the viewpoint’s authors add screening for vitamin D levels in blood and prescribing vitamin D supplements have increased nationally in recent years. The authors write (and we quote): ‘Many primary care clinicians now include blood tests to measure vitamin D concentrations as part of routine laboratory work, and recommend vitamin D supplements, often at high doses’ (end of quote).

Nevertheless, the authors note after a careful review of existing evidence both the IOM and the U.S. Preventive Services Task Force found mixed evidence of any patient benefits for conditions other than bone health.

Indeed, the viewpoint’s authors note the IOM kept the recommended daily allowance of vitamin D at current levels. The authors explain the recommended levels are 600 International Units (IU) a day for persons ages 1 through 70, which increase to 800 IU a day for adults after age 70.

The authors note these levels are equivalent to three or four daily servings of fortified foods such as: milk, yogurt, soy beverages, orange juice, cereal, or eating fatty fish twice a week.

The authors add (and we quote): ‘skepticism regarding the value of high-dose vitamin D supplementation is increasing in the research literature’ (end of quote).

The authors also explain there is some division within the medical community if there is evidentiary merit to invest in more randomized clinical trials to demonstrate the alleged therapeutic value of vitamin D in treating non-bone health related issues.

Overall, the authors conclude physicians should (and we quote) ‘avoid overscreening and overprescribing supplemental vitamin D. Doing so is not only in the best interest of current patients but will also help advance knowledge to benefit future patients and inform future public health recommendations’ (end of quote).

Meanwhile, MedlinePlus.gov’s vitamin D health topic page provides a number of helpful resources about taking the supplement, which is widely available throughout the U.S. without a prescription. For example, the University of Florida Institute of Food and Agricultural Sciences provides an overview of vitamin D and health in a website that is available within the ‘overviews’ section of MedlinePlus.gov’s vitamin D health topic page.

Some helpful information about screening for vitamin D deficiencies (from the American Association for Clinical Chemistry) is available in the ‘diagnosis/symptoms’ section of MedlinePlus.gov’s vitamin D health topic page.

MedlinePlus.gov’s vitamin D health topic page additionally provides links to the latest pertinent journal research articles, which are available in the ‘journal articles’ section. Links to clinical trials that may be occurring in your area are available in the ‘clinical trials’ section. You can sign up to receive updates about Vitamin D as they become available on MedlinePlus.gov.

To find MedlinePlus.gov’s vitamin D health topic page type ‘vitamin D’ in the search box on MedlinePlus.gov’s home page, then, click on ‘vitamin D (National Library of Medicine).’

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It was nice to be with you. I look forward to meeting you here next week