The protection afforded by vitamin D against low radiation damage

Daniel P. Hayes, dhayes@health.nyc.gov
Office of Radiological Health, New York City Department of Health and Mental Hygiene, 2 Lafayette Street, New York, New York 10007, USA
International Journal of Low Radiation 2008 - Vol. 5, No.4 pp. 368 - 394

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.
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First paragraph

An unfulfilled dream of radiobiologists and pharmacologists has been to have a globally
effective pharmacologic agent that could be easily given orally without any due side
effects prior to a suspected or impending nuclear/radiological event. With respect to
cancer, this ideal pharmacologic agent would act by blocking DNA damage that initiates
carcinogenesis and/or by arresting or ameliorating the progression of premalignant
or malignant cells in which such damage has already occurred. Such an ideal
pharmacological radioprotective agent has yet to be identified, let alone developed and
approved for human use (Maisin, 1998). But it is accepted that select types of dietary
supplements can provide some degree of protection against sublethal ionising radiation
injury (Seed, 2005). Among nonpharmacologic agents providing some protection against
radiation-induced cancer are fruits and vegetables whose role has been reviewed and
discussed by Hayes (2003; 2005; 2006). This report will propose and develop the
proposition that vitamin D should be considered among the prime (if not the primary)
nonpharmacologic agents which protect against sublethal low-radiation damage, and
especially against radiation-induced cancer. Succeeding sections of this paper will be
devoted to the following topics:

low-dose and low-dose-rate radiation
vitamin D – background
vitamin D – physiology and biochemistry
vitamin D – human treatment
vitamin D – mechanisms involved in its protective effects including
- cell cycle regulation and proliferation
- cellular differentiation and communication
- Programmed Cell Death (PCD)
- antiangiogenesis
vitamin D and radiation
Summary and general conclusions.

CLICK HERE for full paper

Notes:

Defines 'low-dose radiation' as less than 100-200 millisieverts
Does not indicate how much vitamin D
- VitaminDWiki will guess 4,000 IU to 10,000 daily
Does not indicate relative benefits of vitamin D vs. say Potassium Iodide
Has extensive bibliography

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Could Vitamin D Save Us From Radiation? (2008 News item from Science Daily)

ScienceDaily (Nov. 8, 2008) — Radiological health expert Daniel Hayes, Ph.D., of the New York City Department of Health and Mental Hygiene suggests that a form of vitamin D could be one of our body's main protections against damage from low levels of radiation. Writing in the International Journal of Low Radiation, Hayes explains that calcitriol, the active form of vitamin D, may protect us from background radiation and could be used as a safe protective agent before or after a low-level nuclear incident.

Biologists and pharmacologists who specialize in radiation and health are keen to find an effective agent that could be given by mouth, have few side effects and would protect us against a suspected or impending nuclear event, whether an accident, terrorist attack, or other incident.

In terms of protecting people from the long-term effects of radiation, cancer formation would be the main focus. The ideal agent would act by blocking DNA damage or by halting the progression of damaged cells that might eventually grow into cancers.

While a drug is yet to be found with such ideal radio-protective properties, other researchers have demonstrated that certain dietary supplements have at least some of the desired properties. Hayes argues that vitamin D, and in particular its biologically active form, could be the key ingredient in radiological protection.

"Our general understanding and appreciation of the multifaceted protective actions of vitamin D have recently entered a new era," says Hayes, "It is now becoming recognized that its most active molecular form, 1,25-dihydroxyvitamin D3, may offer protection against a variety of radiation- and otherwise-induced damages."

Hayes has reviewed the various biochemical mechanisms by which vitamin D protects users from the low levels of natural radiation released by the rocks on which we stand and the skies above us. He points out that calcitriol is involved in cell cycle regulation and control of proliferation, cellular differentiation and communication between cells, as well as programmed cell death (apoptosis and autophagy) and antiangiogenesis.

Calcitriol is the form of vitamin D that activates the body's Vitamin D Receptor (VDR), which allows gene transcription to take place and the activation of the innate immune response.

It is possible that several of the transcribed by the VDR will help transcribe proteins that protect the body against radiation.

"Vitamin D by its preventive/ameliorating actions should be given serious consideration as a protective agent against sublethal radiation injury, and in particular that induced by low-level radiation," concludes Hayes.

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Radiation units conversion originally from MIT

1 gray (Gy) = 100 rad
1 rad = 10 milligray (mGy)
1 sievert (Sv) = 1,000 millisieverts (mSv) = 1,000,000 microsieverts (?Sv)
1 sievert = 100 rem
1 becquerel (Bq) = 1 count per second (cps)