Most recently, a NEJM paper “Vitamin D Deficiency — Is There Really a Pandemic?” by Manson, Brannon, Rosen, and Taylor explains the big misunderstandings that let some authors conclude that whole populations are being vitamin D deficient. Just to recall, the IOM recommended in 2010 serum concentrations of vitamin D (i.e., 25-hydroxyvitamin D [25(OH)D]) above 20 ng per milliliter (or 50 nmol per liter) as appropriate level and supplementation with 600 to 800 IU per day as Recommended Dietary Allowance (RDA). And here are the 8 facts:
- The RDA reflects the estimated requirement for people at the highest end of the distribution. Practically everyone in the population (at least 97.5%, or within 2 SD of the median) will have a requirement below the RDA!
- The RDA assume minimal to no sun exposure!
- The RDA does NOT provide a “cut point”! It is NOT true that the entire population must have a serum 25(OH)D level above 20 ng per milliliter to achieve good bone health.
- According to NHANES data, less than 6% of US Americans are deficient in vitamin D serum levels!
- The relationship between serum 25(OH)D and PTH is inconsistent, and no clear threshold defining “sufficiency” has been established!
- Vitamin D is a hormone of concern, but current levels of deficiency do not constitute a pandemic!
- There is also a tolerable Upper Intake Level for vitamin D intake with adverse effects! It has been set by the IOM to 4000 IU daily with a resulting serum 25(OH)D concentration of approximately 50 ng per milliliter (125 nmol per liter).
- For otherwise healthy patients (except osteoporosis, osteomalacia, malabsorption, use of anticonvulsants, institutionalization), routine screening is not recommended!
in German: “Ist der Hype bald vorbei?“