Dr. Ann Corson: I treat patients with chronic conditions such as chronic fatigue, Lyme disease, mold-induced illness. I check them all for both 25-hydroxy vitamin D (most doctors check this only) and 1-25 dihydroxy vitamin D. The latter is the active form of the vitamin.
I do this because chronic inflammation present in these illnesses often results in elevated 1-25 vitamin D and low 25 vitamin D. Giving more vitamin D to such patients seems to actually worsen their illness.
