November 7, 2012
Substantially Fewer Americans Need Vitamin D Supplement With New Guidelines

Maywood, IL—According to which guidelines are consulted, most pharmacy patrons who ask about vitamin D supplementation probably don’t need it.

In fact, newer guidelines lowering the recommended blood levels of vitamin D mean that nearly 80 million Americans no longer require supplementation, according to a new study by Loyola University Chicago Stritch School of Medicine.

Institute of Medicine (IoM) guidelines released 2 years ago suggest blood levels are at or above 20 ng/ml are sufficient for vitamin D. Previous guidelines said people needed vitamin D levels above 30 ng/ml.

In a study published recently in the journal PLOS ONE, researchers note that 70.5% of adults with healthy kidneys had vitamin D blood levels that would be considered insufficient under the older guidelines, but that the percentage drops to 30.3% under the newer guidelines.

“The existing controversy over 25[OH]D levels which define ‘insufficiency’ or ‘risk of insufficiency’ requiring supplementation carries substantial public health relevance because approximately half of the U.S. non-institutionalized adult population has a 25[OH]D level within the range of 12–29.9 ng/ml. Thus, the majority of 25[OH]D supplementation is currently for treatment of ‘insufficient’ rather than ‘deficient’ levels of 25[OH]D,” the authors point out.

Holly Kramer, MD, MPH, and colleagues examined data from 15,099 noninstitutionalized adults who participated in the Third National Health and Nutrition Examination Study (NHANES III). Among the 1,097 adults with chronic kidney disease, 76.5% had insufficient vitamin D under the older guidelines, while only 35.4% had insufficient levels under the newer, IOM guidelines.

Extrapolating the results from NHANES III, a representative sample, Kramer and colleagues estimate that a total of 78.7 million adults considered to have insufficient vitamin D levels under the older guidelines would now have sufficient levels under the IOM guidelines.

“The new guidelines have an impact on a large proportion of the population,” Kramer said.

The Institute of Medicine guideline, based on nearly 1,000 published studies and testimony from scientists and other experts, found that vitamin D is essential to avoid poor bone health, such as rickets. It noted, however, that there have been conflicting and mixed results in studies on whether vitamin D can also protect against cancer, heart disease, autoimmune diseases, and diabetes, also pointing that excessive vitamin D can damage the kidneys and heart.

The IoM guidelines are controversial among some vitamin D supplementation proponents, and not all medical specialty groups have decided to follow them.

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