Vitamin D - The Sunshine Vitamin
Current research is revealing that Vitamin D is not actually a vitamin, but a hormone that is more important to our health than we ever knew.
Vitamin D insufficiency is highly prevalent across all age groups, geographic regions, and seasons, and has recently been implicated in the development of cancer, viral infections, asthma, diabetes, hypertension, autoimmune diseases, tuberculosis, cardiovascular disease, autism, and other conditions.
The term 'vitamin D' usually refers collectively to two molecules, cholecalciferol (D3) and ergocalciferol (D2). In humans, D3 is made in skin cells exposed to UV-B light. D2 is derived from plant sterols, and has frequently been used in Vitamin D supplements. Both vitamin D2 and D3, from the diet or UV-B conversion, are converted by the liver to 25-hydroxyvitamin D, which is the functional indicator of vitamin D status.
Studies also show that 25-hydroxyvitamin D measurements vary widely depending on the method used and/or the laboratory performing the test. The EMH Reference Laboratory uses the FDA-approved DiaSorin Liason® Total-D™ assay, a chemiluminescence immunoassay method, to provide reliable measurements of circulating total (D2 + D3) 25-hydroxyvitamin D.
Understanding that a sufficient vitamin D level has a much greater impact on overall health than once thought, the optimal blood level of 25-hydroxyvitamin D has proved controversial. It has been recognized, however, that population-based reference values derived from apparently healthy individuals are usually too low. The reference ranges below are based on physiological insufficiency as defined by 25-hydroxyvitamin D levels below those where parathyroid levels increase in a population.
| Severely deficient | <10 ng/mL |
| Insufficient | 10-29.9 ng/mL |
| Optimal | 30-100 ng/mL |
| Potentially toxic | >100 ng/mL |