About a decade ago, labs realized that the tests commonly used to measure vitamin D levels (1, 25 OH vitamin D) were measuring the inactive vitamin D precursor. With the implementation of the appropriate vitamin D test (25 OH vitamin D) it soon became apparent that vitamin D insufficiency is widespread.

Vitamin D deficiency and insufficiency both have profound effects on our general health. Low vitamin D levels have been found to contribute to the development of heart disease, autoimmune disease, dementia, and various cancers.

Supplementation with vitamin D has been shown to increase the number of regulatory T lymphocyte cells that restore immune system activity to its normal state, preventing the overactive response characteristic of autoimmune disease. The goal in supplementation is to reach an optimal 25 OH vitamin D level of 50 --80 ng/ml.