The fallout from radioactive steam released by damaged nuclear reactors in Japan has raised concerns about radiation exposure in Asia, the Pacific and North America.
The disaster at Chernobyl in the Ukraine in 1986 provides an alarming example of how radiation can spread over long distances and in unsuspected ways.
Risk of Radiation Entering the Food Supply
For people outside of Japan, the most likely risk comes from ingestion of foods contaminated with radioactive isotopes of minerals like iodine, strontium and cesium.
Scientists note: "millions of people were exposed to radioactive isotopes in the fallout from the Chernobyl accident, within the first 20 years there was a large increase in thyroid carcinoma incidence and a possible radiation-related increase in breast cancer..." 
Following Chernobyl studies found an increase in the incidence of thyroid cancer and childhood leukemia that extended as far as Scotland and Wales in the United Kingdom. [2,3]
Iodine pills have been distributed in Japan, and are one of the key therapies used for protection against radiation. As they have been written about extensively, I take a brief look at iodine below.
Radiation Protection from Supplments?
Because of the health risks of radiation exposure, scientists have searched extensively for other dietary supplements that might help protect healthy cells from radiation toxicity. In other words, they are looking for supplements that could be "radioprotective." Although there is no guarantee that the dietary supplements I report on here will protect us from radiation, it is interesting to know about the research done in this area.
Because strontium absorption is significantly blocked by calcium, high calcium intake from food or supplements may offer protection against absorption of radioactive strontium from food . Calcium supplements must be taken with food for this effect to occur.
Scientists at the Institute of Radiation Protection in Germany examined the effect of sodium alginate, a seaweed extract that is used as a food thickener and is available as an over-the-counter heartburn remedy, on the gastrointestinal absorption of strontium. Writing in the journal Health Physics, they explain "Sodium alginate was proven to be a potent agent for reducing strontium absorption with high efficiency and virtually no toxicity. The data obtained show that the uptake of ingested strontium from milk was reduced by a factor of nine when alginate was added to milk."  To block strontium absorption from contaminated food, alginate must also be taken at the same time as food.
Ginkgo Leaf Extract
Following the tragedy at Chernobyl, scientists in the Soviet Union and elsewhere studied several natural products to see if they could reverse evidence of radiation-induced damage in responders and in people living near the disaster site.
Most of the research involved products not readily available outside the Soviet Union, but one study utilized a Ginkgo biloba extract, Egb 761, that is available in North America. According to scientists at the National Center for Scientific Research in Paris the administration of Egb 761, 40 milligrams three times a day for two months, to workers at Chernobyl helped to significantly decrease evidence of radiation damage in blood, the benefits persisting for several months after administration of the Ginkgo extract ended .
Italian researchers from the University of Pisa found similar protective effects of Egb 761 in patients exposed to high dose radioactive iodine .
Learn more about Ginkgo: Ginkgo Leaf Extract -- Know What Herbs Do What
"Fresh (raw) ginkgo seeds contain large amounts of a chemical called ginkgotoxin, which can cause serious adverse reactions -- even seizures and death. Roasted seeds can also be dangerous. Products made from standardized ginkgo leaf extracts contain little ginkgotoxin..."  according to the National Center for Complementary and Alternative Medicine, part of the National Institutes of Health. (NIH)
Laboratory Studies on Hesperidin and Hawthorn
Several other natural products have been the subject of laboratory studies for their radioprotective effects. Three basic methods for testing have been used but only one method is likely to be instructive in terms of what might happen in the real world.
The most common research methods involve adding the substance to cells in a test tube and then exposing the cells to high dose radiation or feeding the substance to mice and then exposing the animals to total body radiation.
The doses used in these studies are rarely reflective of what would happen in a human being taking a dietary supplement, so their relevance is questionable.
Two substances have been studied by a technique that may be more relevant: a human volunteer takes one or more doses of the product by mouth and then has blood drawn at various intervals.
The blood, now outside of the body, is then exposed to radiation and the white blood cells are examined for signs of damage. This is called an "ex vivo" study.
If the blood cells from the people taking the supplements were found to be less sensitive to the damaging effects of radiation than those receiving placebo, that might indicate a radioprotective effect.
Two research studies have demonstrated the potential of dietary supplements for ex vivo radioprotection: hesperidin and hawthorn.
One interesting study was published in the Oxford University Press Journal Mutagenesis. The researchers looked at Hesperidin, a flavonoid found naturally in fruits, especially citrus, and available as a dietary supplement. They note that "Hesperidin has been reported to have many biological effects including anti-inflammatory, antimicrobial, anticarcinogenic, antioxidant effects..." and refer to their previous study "Recently, we showed the hesperidin, a flavonoid, has powerful protection effects on DNA damage, reducing the frequency of micronuclei induced by γ-irradiation in mice."  That study was published in the British Journal of Radiology.
In the Mutagenesis ex-vivo study, the data suggest that a single dose of 250 milligrams of hesperidin helped decrease radiation damage to the blood cells tested by one-third.  The peak effect was observed at one hour. It should be noted that the study was very small, with blood samples taken from five volunteers, all healthy non-smoking males.
The second study, done by the same research team and published in the journal Radiation and Environmental Biophysics, examined hawthorn (Crataegus microphylla) an herb commonly used for cardiovascular effects. The data from the study suggest that a single dose of 500 milligrams of Hawthorn helped reduce radiation damage to the blood cells tested an average of 44 percent. Hawthorn also showed its peak effect one hour after administration. (11) This study was also very small, with blood samples taken from five volunteers.
For general information on hawthorn, including traditional uses and side effects, see: Hawthorn -- Know What Herbs Do What
Iodine Therapy Used to Block Radioactive Iodine
Because it is concentrated in the thyroid gland, the main toxicity of radioactive iodine is to the thyroid gland. The lower the iodine content of the diet, the higher the uptake of radioactive iodine by the thyroid. The Japanese government has distributed iodine tablets to people living in the region of highest radiation exposure. The goal of high dose iodine is to shut down the thyroid, so that radioactive iodine is not absorbed. 
But researchers note that high dose iodine is only effective when administered two days before to eight hours after radiation exposure, so you need to know exactly when exposure occurs.  Prolonged massive iodine supplementation can produce hypothyroidism, a disease with serious health consequences.
Research from Japan done on mice found that increasing consumption of natural iodine from food and supplements, however, might decrease the uptake of radioactive iodine by the thyroid gland.  The Japanese researchers explain: "Thus, we conclude that previously fed iodine-rich material, especially dietary seaweeds rich in iodine and other minerals, vitamins, and beta-carotene, such as kelps or laver supplemented with inorganic iodine, may be effective in prevention of internal radiation injury of the thyroid." 
Now I'd like to hear from you...
What are your concerns about radiation exposure?
What steps have you taken to prevent or reduce exposure?
Have you taken anything for it?
Please let me know your thoughts by posting a comment below.
Leo Galland, M.D.
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Leo Galland, MD is a board-certified internist, author and internationally recognized leader in integrated medicine. Dr. Galland is the founder of Pill Advised, a web application for learning about medications, supplements and food. Sign up for FREE to discover how your medications and vitamins interact. Watch his videos on YouTube and join the Pill Advised Facebook page.
 Oncogene. 2008 Dec;27 Suppl 2:S9-18. "Radiation carcinogenesis: lessons from Chernobyl." Williams D.
 Int J Environ Res Public Health. 2009 Dec;6(12):3105-14. "Very low dose fetal exposure to Chernobyl contamination resulted in increases in infant leukemia in Europe and raises questions about current radiation risk models." Busby CC.
 Health Phys. 2002 Jul;83(1):56-65. "Absorption of strontium from the gastrointestinal tract into plasma in healthy human adults." Apostoaei AI. SENES, Oak Ridge, TN, USA.
 Health Phys. 2004 Feb;86(2):193-6. "Strontium biokinetics in humans: influence of alginate on the uptake of ingested strontium." Höllriegl V, Röhmuss M, Oeh U, Roth P. GSF-National Research Centre for Environment and Health, Institute of Radiation Protection, Ingolstadter Landstrasse 1, D-85764, Neuherberg, Germany.
 Radiat Res. 1995 Nov;144(2):198-205. Clastogenic factors in the plasma of Chernobyl accident recovery workers: anticlastogenic effect of Ginkgo biloba extract. Emerit I, Oganesian N, Sarkisian T, Arutyunyan R, Pogosian A, Asrian K, Levy A, Cernjavski L. Department of Genetics, CNRS, Paris, France.
 J Clin Endocrinol Metab. 2007 Nov;92(11):4286-9. Epub 2007 Aug 21."Anticlastogenic effect of Ginkgo biloba extract in Graves' disease patients receiving radioiodine therapy." Dardano A, Ballardin M, Ferdeghini M, Lazzeri E, Traino C, Caraccio N, Mariani G, Barale R, Monzani F. Department of Internal Medicine, University of Pisa, Italy.
 "Ginkgo Biloba fact sheet", Created September 2005, Updated July 2010, National Center for Complementary and Alternative Medicine
 Mutagenesis. 2009 May;24(3):233-5. "Radioprotective effects of hesperidin against genotoxicity induced by gamma-irradiation in human lymphocytes" Hosseinimehr SJ, Mahmoudzadeh A, Ahmadi A, Mohamadifar S, Akhlaghpoor S.
 Radiat Environ Biophys. 2009 Feb;48(1):95-8. "Radioprotective effects of Hawthorn against genotoxicity induced by gamma irradiation in human blood lymphocytes" Hosseinimehr SJ, Mahmoudzadeh A, Azadbakht M, Akhlaghpoor S.
 Radiat Prot Dosimetry. 2008;130(4):499-502. "Age-dependent potassium iodide effect on the thyroid irradiation by 131I and 133I in the nuclear emergency." Jang M, Kim HK, Choi CW, Kang CS.
 Health Phys. 2000 Jun;78(6):660-7. "Effects of time of administration and dietary iodine levels on potassium iodide (KI) blockade of thyroid irradiation by 131I from radioactive fallout." Zanzonico PB, Becker DV.
 Kitasato Arch Exp Med. 1992 Dec;65(4):209-16. "Suppression of 125I-uptake in mouse thyroid by seaweed feeding: possible preventative effect of dietary seaweed on internal radiation injury of the thyroid by radioactive iodine." Maruyama H, Yamamoto I. Department of Pathology, Kitasato University School of Hygienic Sciences, Kanagawa, Japan.
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