Our general understanding and appreciation of the multifaceted protective actions of vitamin D have recently entered a new era. It is now becoming recognised that its most active molecular form, 1,25-dihydroxyvitamin D3 (also known as calcitriol), may offer protection against a variety of radiation- and otherwise-induced damages. As will be discussed, vitamin D carries out its protective actions by a host of mechanisms, among these being cell cycle regulation and proliferation, cellular differentiation and communication, Programmed Cell Death (PCD) (apoptosis and autophagy) and antiangiogenesis. As will be proposed and developed, vitamin D, with its preventative/ameliorating actions, should be considered among the prime (if not the primary) nonpharmacological agents that offer protection against sublethal low radiation damage and, in particular, against radiation-induced cancer.

Keywords: low radiation, vitamin D, 1,25-dihydroxyvitamin D3, apoptosis, autophagy, cell regulation, cellular communication, DNA damage, radiation-induced cancer, hormesis, radiation protectors, calcitriol, radiation damage, antiangiogenesis, cell cycle regulation, cellular differentiation