There are, however, different forms of vitamin D. The form of vitamin D we get from food, diet, supplements and sun exposure is called D3. D3 is converted by the liver into a storage form 25-D, which functions as a steroid. 1,25-D, the activated form of vitamin D, functions as both a steroid and a hormone. It is produced inside various types of cells, including those of the immune system and the kidneys, as well as in response to sunlight.[i] Unfortunately, most doctors only test for the storage form of D and not the activated form, leading to an incomplete picture of actual vitamin D status.
The vitamin D that we get from the sun is a sulfate form and is water soluble. It is able to travel freely in the blood stream, strengthens the immune system, protects against cardiovascular disease, helps fight depression, assists with detoxification, and nourishes the brain. The supplement form of vitamin D is un-sulfated, and not water soluble, which is why taking too much can be harmful. Additionally, vitamin D supplementation directly lowers potassium, and vitamin A status, while raising calcium levels. As the Ca/K ratio increases, the thyroid gland slows down. With the loss of potassium, the sodium to potassium ratio (Na/K) increases, causing an increased stress response and loss of magnesium. Magnesium deficiency has been linked to heart attacks, diabetes, anxiety and unstable blood sugar levels. The loss of vitamin A impairs the body’s ability to decrease inflammation and also negatively affects the utilization and transport of iron, which in turn can potentially lead to anemia.[ii]
The question that we should be asking with respect to vitamin D is whether low test results are a cause or effect of chronic disease and is supplementation a cause or a cure for disease. Furthermore, the methodologies of a specific research study should be examined when determining the merits of the conclusion. For example, there is published research claiming, “Findings from this study suggest that higher intakes of calcium and vitamin D may be associated with a lower risk of developing premenopausal breast cancer.”[iii] What is not made clear from the conclusion of the study is that women in the group who consumed higher levels of vitamin D were 67% less likely to be a smoker, burned over 39% more calories in physical activity, and drank about a fifth less alcohol. [iv]
A recent study by the National Cancer Institute, the first study to actually look at the relationship between measured vitamin D in the blood and subsequent total cancer deaths, failed to show an association between baseline vitamin D status and overall cancer risk in men, women, non-Hispanic whites, non-Hispanic blacks, Mexican Americans, and in persons younger than 70 or 70 years or older.[v]
So why are doctors recommending vitamin D supplementation? If you review research studies that follow subjects for only a few years, researchers find that vitamin D seems to be “preventing” cancer. What they are actually picking up is the temporary decrease in cytokine production that results when 25-D slows the immune system and less L-form bacteria are killed. Cytokines are cell signaling molecules that aid cell to cell communication in immune responses and stimulate the movement of cells towards sites of inflammation, infection, and trauma. So in the short term, as less bacteria die, less cytokines are released into the tissues, resulting in a temporary decrease in inflammation. But in the long run, L-form bacteria will take full advantage of the subjects’ weakened immune system by increasing in number and spreading to new tissues and organs.[vi]
What to do: Do not take vitamin D supplementation blindly. Ask your doctor to test for both the storage form of vitamin D 25(OH)D and the activated form (1,25(OH)2 D3). To naturally optimize your vitamin D levels, consider exposing large parts of the body to the sun in midday, if and when possible. You want to do so in a safe manner, limiting exposure to about 20 minutes per side or until the skin turns the lightest shade of pink.
If you do choose to supplement your vitamin D, research shows D3 to be 87 percent more potent in raising and maintaining storage levels than the synthetic D2 form and D3 seems to convert to the active form 500 percent faster than D2. Drisdol is the prescription form of vitamin D2, which is in fact different than what is produced by the body in response to sun exposure. Vitamin D2 is made by irradiating fungus and plant matter.[vii]
If you have been supplementing with vitamin D for some time, consider doing a Hair Tissue Mineral Analysis (HTMAtest.com) test to determine your current mineral status. After recently learning about the darker side of vitamin D supplementation, I have had the analysis, only to find that indeed, my potassium, magnesium, and vitamin A levels are low and not surprisingly, my thyroid is slow requiring hormone supplementation. You must make these decisions for yourself, but I have chosen to stop supplementing D3 while adding minerals recommended by the HTMA results. A retest in several months should shed interesting light on my vitamin/mineral status.
[i] Marshall, T. G. (2006). Molecular mechanisms driving the current epidemic of chronic disease.
[iii] Marks, R., Foley, P. A., Jolley, D., Knight, K. R., Harrison, J., Thompson, S. C., et al. (1995). The effect of regular sunscreen use on vitamin D levels in an Australian population. Results of a randomized controlled trial. Archives of dermatology, 131(4), 415-21.
[v] Nedelman, J. (2003).