Vitamin D Impairs Low Level Radiation
An Emerging Role for the Steroid Hormone
Mar 22, 2009 Alicia Richardson
Radiological expert Dr. Daniel Hays of the New York City's Department of Health said: "Our understanding and appreciation of the multi-protective actions of vitamin D have recently entered a new era. It is becoming recognized that its most active molecular form - 1,25 dihydroxyvitamin D3 - may offer protection against a variety of radiation and otherwise - induced damages. It's 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." His report was published in the 2008 issue of The International Journal of Low Radiation.
Sources of Radiation
All living organisms (including humans) are continuously exposed to low-level radiation. It comes from the sun, the stars, and other heavenly bodies, and the earth's rocks, soil, and water. It also comes from man-made products and devices such as medical equipments used for diagnostic imaging, lightning rods, smoke detectors, medical and food sterilizing machines, antistatic devices, fuel reactors, etc.
Physiological Effects of Radiation on Humans
Radiation causes ionization in all living cells - a process whereby ions react with other atoms in the cell causing damage that impairs cell processes and cell growth. At low dosages, the human body may be able to repair damages incurred, but at higher doses, the cells may be unable to repair injuries and the cells can either die or mutate and become malignant.
Cells that divide rapidly (blood, skin, and cells that line the gastrointestinal tract) are more vulnerable to radiation than cells that divide more slowly such as nerve and brain cells. Whole body exposure carries a greater risk than dose to a body part.
Acute radiation poisoning includes skin reddening, vomitting or nausea, and dehydration. Long term exposure may increase one's risk of cancer and birth defects in pregnant women due to somatic cell mutations.
The Chemoprotective Role of Vitamin D3
Bioactive vitamin D regulates the cell cycle by controlling growth/proliferation, differentiation, communication, apoptosis (programmed cell death), autophagy (self-cannibalism), and antiangiogenesis (prevents the formation of new blood vessels) of cells. It also activates the body's vitamin D receptor (VDR) which allows gene transcription to take place and the activation of the body's immune response. It is possible that several of the transcribed proteins are protective against radiation.
In human leukemic cells, vitamin D3 suppressed cell division and induced differentiation by down regulating oncogen expression.
Dietary Reference Intakes for Vitamin D expressed as Average Intakes (AIs)
The minimum recommended Average Intakes for healthy persons are as follows:
- Both genders: Infants and adults ( ages 0 - 50 years) 5 micrograms/day
- Both genders: Adults (51 - 70 years ) 10 micrograms /day
- Both genders: Adults (71 years and older ) 15 micrograms/day
Note: The Tolerable Upper Levels for adults is 50 micrograms per day. 1 International Unit (IU) =2.5 micrograms. 400 (IUs) = 10 micrograms. In general, dietary vitamin D supplies a mere 20% of the body's daily vitamin D requirements.
Excellent Dietary Sources of Vitamin D
Fortified milk and margarine, butter, eggyoks, liver, veal, beef, fatty fish like salmon, herring, sardines and oils, also cod liver oil.
References
Sheng C et al. "Modulating Effects of 1,25 Dihydroxyvitamin D3 on Human B Cell Differentiation" The Journal of Immunology 2007;179:1634-1647
Whitney EN & Rolfes SR "The Fat-Soluble Vitamins : A, D, E and K" Understanding Nutrition Wadsworth, CA 2002 pp: 364-367
Hayes DP "The protection offered by vitamin D against low radiation damage" International Journal of Radiation 2008; 5(4):368-394
Milk, butter, margarine, and eggs
|
More in Health & Wellness
Latest Articles