Vitamin D was the topic of a symposium attended by hundreds of clinicians at the American Society for Bone and Mineral Research (ASBMR) 2012 meeting. Vitamin D3, D2, 25-hydroxy, 1-25-dihydroxy, 24-25-dihydroxy, and differnt assays. All the variations lead to confusing research results as we try to understand Vitamin D and how it works.
Dr Neil Binkley, of the University of Wisconsin, gave the summary presentation about Vitamin D dosing and measurement of blood levels. He gave a plea for everyone to switch to Vitamin D3, now that it is cheaper than D2, and available in prescription level doses.
I have made Vitamin D3 in 50,000 unit capsules available to my patients for the last 3 years, dispensed by my office. Finally some pharmacies are carrying it as well.
Vitamin D3 (Cholecalciferol) is what our bodies can make naturally from sunshine during the summer. Once activated by the kidneys, it lasts for about 2 weeks before being metabolized and excreted. D3 is the natural Vitamin D in people.
People can also use the plant substance, Vitamin D2 (Ergocalciferol). It is also activated in the kidneys, but only lasts 2-3 days before it is metabolized and excreted. Therefore’ people need much higher doses of (plant sterol) D2 to maintain adequate blood levels of the active (1-25-dihydroxy) form. Dr Binkley also emphasized that D2 is more difficult to measure accurately in the blood, leading to dosing confusion.
Take Control Naturally with the natural Vitamin D for people, Vitamin D3.
Jay Ginther, MD