We have vitamin D receptors and activating enzymes throughout our bodies to function. Every cell in our body has a nucleus that interacts with vitamin D. 2

Vitamin D comes in many forms. It starts with cholesterol molecules, which we can call vitamin D1. Near the surface of the skin, it is interrupted by sunlight and becomes vitamin D2 (ergocalciferol). It is then converted to vitamin D3 (cholesterol) by an activating enzyme (usually in the liver) and converted to the most active form of vitamin D4 (calciferol) by the kidneys. 1

When the vitamin D content in the body is extremely low, the parathyroid glands are affected and this is usually compensated by releasing more parathyroid hormones. This hormone usually deposits calcium into the bones. Vitamin D allows calcium to be absorbed from the gut into the bloodstream. When vitamin D is not present, calcium is not abundant and the parathyroid glands are unable to function. Because they have a three-way relationship with calcium, parathyroid glands and vitamin D.

In other cases, healthy individuals returning low vitamin D to normal levels can bring great health benefits. But for an unhealthy person, returning vitamin D levels to normal levels may not be enough to cause noticeable changes. However, by returning low levels of vitamin D to normal levels, symptoms can be relieved and disease can be improved. The patient's energy, mood, and pain may improve