Fatal underdose 27. April 2008 William Davis (8) Since vitamin D has been the topic of a fair amount of media coverage, I've received many questions about this fascinating "nutrient." A day doesn't go by without several nurses, friends, even fellow physicians stopping me to ask about vitamin D. When I inform them that the average dose for females in this region (upper Midwest) is 4000-5000 units per day, 5000-6000 units per day for males, they are all surprised. "Then why did they say just take your multivitamin every day, or just drink your milk on the news?"Many people are even more surprised, sometimes completely turned off, when they hear that, to be truly confident of adequate vitamin D dosing, a blood level of 25(OH) vitamin D3 needs to be checked. Now we're talking real hassle!But there is no other way to do it. In order to obtain the full potential benefits of vitamin D, such as reduction in blood sugar and sensitization to insulin, reduction in cancer risk (especially prostate, colon, and breast), reductions in blood pressure, increased bone density, not to mention markedly increasing the likelihood of stopping or reducing your heart scan score, then achieving a desirable blood level of 25(OH) vitamin D is necessary. Checking a blood level of vitamin D is no more difficult than having a cholesterol test, unless, of course, your doctor balks at the idea. (Time for a new doctor if that occurs.)All too often, someone will be convinced they are taking a sufficient dose of vitamin D of, say 2000 units per day, only to discover that their blood level of 25(OH) vitamin D is something like 17 ng/ml--severe deficiency, sufficient to leave them exposed to all the undesirable consequences of vitamin D deficiency. Even though 2000 units per day represents 500% of the Institute of Medicine's recommended Adequate Intake for adults, to those familiar with the Track Your Plaque program it likely sounds like a child's dose. Many variables enter into the equation in your body that determines your need for vitamin D: body size (heavier or larger people need more, with obese people often requiring enormous doses); sex (men need more than women); age (aging results in dramatic loss of ability to activate vitamin D in the skin); race; skin color (darker skinned people require more). Trying to guess your need is a fool's game. It's also a game that can seriously compromise your health and your hopes of ever stopping or reducing your heart scan score. The message is clear: You cannot guess what your vitamin D need is. You cannot properly judge your vitamin D requirement by your age, body size, sex, or any other characteristic. Having a tan or a lack of a tan is a lousy indicator, as well. A simple blood level of 25(OH) vitamin D is an absolute necessity to gauge your vitamin D status, both before starting and while on your supplement. Members of Track Your Plaque: Watch for the 30-some page booklet, The Track Your Plaque Complete Handbook on Vitamin D and Heart Health, which will be released in the next day or two. Copyright 2008 William Davis, MD