Abstract

In the past three decades, the number of peer reviewed articles concerning vitamin D has gone from under a hundred per year to thousands. With the increase in published articles has come an increase in controversy. Some suggest that vitamin D as the preprohormone of the active form—calcitriol or 1,25-dihydroxy-vitamin D (1,25(OH)₂D)—is an enabler of various processes in the body (1), that include both innate and adaptive immune functions and explain vitamin D’s link with long latency diseases such as multiple sclerosis (2, 3), diabetes (4-7), rheumatoid arthritis (8, 9), certain cancers (prostate (10) and colon (11, 12) cancers), autism (13-16), and infections such as tuberculosis (17), and derangement in placental function that manifests as preeclampsia and premature birth, and later childhood asthma (18-22). There are as many articles showing benefit as there are negative studies. It is confusing and problematic for health care providers and policy makers. While no one would dispute vitamin D’s endocrine function in helping maintain calcium and phosphate metabolism (23), the confusion surrounds whether vitamin D has the capacity to change an individual’s health trajectory.