Supplemental vitamin D comes in two forms: ergocalciferol (vitamin D2) and cholecalciferol (vitamin D3).
They have generally been regarded as equivalent and interchangeable, but that notion is based on studies of rickets prevention in infants conducted seven decades ago.
Recent studies have shown that vitamin D3 is a more potent form of vitamin D. Vitamin D2 has a shorter shelf life, and its metabolites bind with protein poorly, making it less effective. One unit of cod liver oil (containing vitamin D3) has been shown to be as effective as four units of Viosterol (a medicinal preparation of vitamin D2).
However, the form of vitamin D used in prescriptions in North America is almost invariably vitamin D2.
How Vitamin D Performance Testing Can Help Optimize Your Health
A robust and growing body of research clearly shows that vitamin D is absolutely critical for good health and disease prevention. Vitamin D affects your DNA through vitamin D receptors (VDRs), which bind to specific locations of the human genome. Scientists have identified nearly 3,000 genes that are influenced by vitamin D levels, and vitamin D receptors have been found throughout the human body.
Is it any wonder then that no matter what disease or condition is investigated, vitamin D appears to play a crucial role? This is why I am so excited about the D*Action Project by GrassrootsHealth. It is showing how you can take action today on known science with a consensus of experts without waiting for institutional lethargy. It has shown how by combining the science of measurement (of vitamin D levels) with the personal choice of taking action and, the value of education about individual measures that one can truly be in charge of their own health.
In order to spread this health movement to more communities, the project needs your involvement. This was an ongoing campaign during the month of February, and will become an annual event.
To participate, simply purchase the D*Action Measurement Kit and follow the registration instructions included. (Please note that 100 percent of the proceeds from the kits go to fund the research project. I do not charge a single dime as a distributor of the test kits.)
As a participant, you agree to test your vitamin D levels twice a year during a five-year study, and share your health status to demonstrate the public health impact of this nutrient. There is a $65 fee every six months for your sponsorship of this research project, which includes a test kit to be used at home, and electronic reports on your ongoing progress. You will get a follow up email every six months reminding you "it's time for your next test and health survey."