Q: Vitamin D is an important nutrient for bone health, but I don’t get outside often. Can vitamin D be absorbed through a window?
A: The UVB rays needed for your body to produce vitamin D do not penetrate glass very well, so exposure to sunshine indoors through a window or through your car window will not likely be sufficient for your skin to synthesize vitamin D. Experts are undecided as to how much direct exposure to sunlight is needed, recommending anywhere from five to thirty minutes several times per week. If you can’t get outside, a tanning bed will provide the necessary light but use it with caution. Today safer beds are available specifically for this purpose. Ensure, of course, that your diet provides vitamin D or include a daily supplement.
