I attribute much of our epidemic of Vitamin D deficiency to our sedentary lifestyles lived largely indoors. Dietary sources of Vitamin D such as fatty fish are also consumed infrequently by most Americans and their acidic diets high in sugar, grains, dairy, and grain-fed animal fats. Darker skinned individuals are at greater risk for deficiency as more sunlight is needed to produce healthy levels of Vitamin D.
Much of the negative effects of our diet is that we do not balance it with liberal quantities of vegetables, especially of the green leafy variety which are also dietary sources of calcium!
Even more interesting is that Vitamin D supports much more than bone health and calcium metabolism. Vitamin D actually modulates on the genetic level (influences over 200 genes) and there are vitamin D receptors on every tissue in the human body!
Written by Alex of DrAlexRinehart.com