Life Extension Magazine August 2010
Protect your DNA from CT Scans and X-rays
Research Supports Nutrient Shields Against Ionizing Radiation
By Robert Klein
In hospitals and doctors’ offices around the country, millions of innocent patients are unknowingly exposed to excessive radiation. The main culprit is the computed tomography (CT) scan which exposes patients to the equivalent amount of radiation received by atomic bomb survivors in the low-dose range.1
Published scientific studies document that these excessive amounts of radiation will result in catastrophic numbers of new cancers due to DNA mutation.1-3 Epidemiologists estimate that as many as 29,000 new cancers could be related to CT scans performed in the US in 2007 alone.2 There are now approximately 70 million CT scans performed every year, up from a mere 3 million in 1980.4,5
As if this were not bad enough, shocking revelations in the New York Times and scientific publications last year exposed frightening inattention to the risks of X-ray equipment, specifically computed tomography (CT) scanners.6-8 In one case, more than 200 older adults received up to 8 times the normal radiation dose during brain scans.6 In another, a 2-year-old boy was left with visible skin changes and a significant probability of cataracts within a few years, following lengthy over-exposure.6
While CT scans provide important diagnostic information that can save lives, their growing frequency is putting an enormous population at risk for a range of lethal cancers. Most likely everyone reading this article will have one or more CT scans in the coming years. Fortunately, new research shows that a number of readily available antioxidant nutrients and herbs can offer levels of protection against the dangers of ionizing radiation found in X-rays and CT scans.
What follows is an analysis of recent studies showing how certain remarkable nutrients can ward off many dangers associated with medical-based diagnostic radiation exposure.
Antioxidant Protect Against Radiation
Ionizing radiation (principally X-rays and gamma rays), when it interacts with living tissue, releases massive amounts of reactive oxygen and nitrogen species.9
The pathological result is free radical damage to vulnerable DNA strands.10 When DNA genes that regulate cellular proliferation are damaged, the result can be cancer formation.
By interrupting oxidant processes, one can reduce the risk of radiation-induced cancers.11,12 Overlooked by most physicians and radiologists is the role of nutritional supplements in providing impressive protection from ionizing radiation.11,13
If your physician orders a CT scan, X-ray, or other diagnostic procedure involving radiation, optimize your dosing of antioxidant supplements as soon as you are scheduled. There are several classes of nutrients that have been studied for their radioprotective capabilities. In this article we will examine vitamins, trace minerals, polyphenols, and various plant extracts as a way to shield yourself from the dangers of medical radiation diagnostics.
Polyphenols are versatile molecules found in plant products. Research has shown that they provide a multitude of key protective benefits, including modifying gene expression that protects tissues from ionizing radiation. Collectively, polyphenols offer important protection from some of radiation’s impact on the body.14,15
Resveratrol, quercetin, and green tea polyphenols rank among the best-studied and most potent radioprotectants in this class. Resveratrol is both radioprotective in healthy tissue and also has antitumor activity.16-18 Resveratrol protects mouse chromosomes from radiation-induced damage.19 Its antioxidant properties prevent radiation toxicity to the liver and small intestines, two tissues most immediately sensitive to radiation’s ill effects.20
Quercetin and its related compounds protect lipids and proteins from otherwise-lethal doses of gamma radiation, again largely through their antioxidant properties.21 Quercetin and other polyphenols not only provide chromosomal radioprotection, but also shield mitochondrial DNA from radiation-induced oxidant damage.22 Quercetin also ameliorates biochemical changes in human white blood cells following radiation exposure.23
The polyphenol epigallocatechin gallate (EGCG) derived from green tea also protects animals from whole-body radiation, blocking lipid oxidation and prolonging life span.24 Green tea extracts can protect rapidly-reproducing cells in the intestine and hair follicles from the damaging effects of radiation therapy, a form of radiation exposure far more intense than typical CT doses.25,26
Soybeans contain a wealth of health-promoting substances, several of which have remarkable radioprotective effects. Genistein, an isoflavone, can protect mice from ionizing radiation injury after a single dose.27 One mechanism is its protection against radiation-induced lipid peroxidation which disrupts cell membranes and structures.28 Genistein also stimulates production of red and white blood cells following whole-body radiation, again after as little as a single dose.29,30 That’s vital, because rapidly-reproducing blood stem cells in bone marrow are among the most vulnerable to radiation’s killing effects. Because of its powerful induction of cytokines that stimulate new blood cell formation, genistein is under intensive study as a way to protect military and civilian personnel against a potential nuclear threat.31
Soybeans also contain a radioprotective enzyme inhibitor known as the Bowman-Birk Inhibitor (BBI).32 BBI activates genes involved in DNA repair, making it among the most valuable compounds for late (or even post-exposure) treatment of radiation toxicity.33,34 In typical multitargeted fashion, BBI also stabilizes enzymes that would otherwise produce radiation-induced arrest of skin cell growth.35 Remarkably, BBI enhances survival of healthy cells, but not diseased cells, following radiation exposure.36,37 BBI survives processing in commercial soybean products (e.g., soymilk, soybean concentrate, and soy protein isolates), making it a highly accessible radioprotectant.38,39
Herb, Spice, and Other Plant Extracts
Compelling scientific evidence suggests that plant extracts have valuable gene expression-modifying effects that are relevant in protecting our bodies from radiation exposure.
Curcumin, from turmeric and other south Asian spices, has powerful radioprotective effects as a result of its antioxidant-modifying and gene expression-modifying characteristics.40 Curcumin supplements reduce DNA damage and tumor formation in rats; they reduce both DNA damage and lipid peroxidation in cultured human white blood cells.41,42 Curcumin has “dual action.” Its antioxidant effects protect normal tissue from radiation. But it also upregulates genes responsible for cell death in cancers, enhancing tumor destruction by radiation.43 The result is increased survival in animals exposed to high-dose radiation.44
Together, garlic and ginger offer surprising radioprotection. Garlic’s high sulfur content supports natural antioxidant systems like glutathione.45 Garlic extracts protect red blood cells from radiation damage by a glutathione-related mechanism.46 In mice, garlic extracts prevented radiation damage to chromosomes in vulnerable bone marrow cells.47 By a different mechanism (think multitargeting), garlic extracts downregulate X-ray-mediated increases in the inflammatory NF-kappaB system.48 Ginger extracts boost glutathione activity and reduce lipid peroxidation by a separate and complementary mechanism.49 The extracts directly scavenge a host of free oxygen and nitrogen radicals immediately following their formation by radiation.50-52
Ginkgo biloba reduces “clastogenic” factors—DNA damage artifacts in the blood of people and animals exposed to radiation.53,54 Astonishingly, this effect is so powerful that it proved useful in treating workers at the Chernobyl nuclear plant long after their exposure.55 More recently, ginkgo extracts proved to protect animals’ organs from direct radiation-induced damage, and humans from cell damage following radioactive iodine treatment.56,57
Ginseng is another plant important in traditional medicine that has remarkable radioprotective effects.58,59 A variety of ginseng extracts protect against radiation-induced DNA damage.60-62 It protects hair follicles and other rapidly-reproducing (but healthy) tissues from damage by radiation.63,64 Its antioxidant effects have resulted in protection of a variety of radiation-sensitive tissues, including cells in the bone marrow, spleen, and testicles.58,65 Ginseng’s immunomodulatory effects make it especially useful in defending the body against the ravages of radiation injury.66 A North American ginseng extract was recently found to protect human white blood cells from DNA damage even up to 90 minutes following radiation exposure.67 That makes it of great interest to defense and national security researchers.
Silymarin, a milk thistle extract, is well known to protect liver cells from chemical toxins. Not surprisingly, then, silymarin has been found to protect liver tissue from radiation damage as well.68,69 It reduces DNA damage and extends survival in animals exposed to dangerous levels of radiation.70 Silymarin’s free radical scavenging and direct antioxidant effects are credited with producing these results.71
N-Acetyl Cysteine (NAC)
N-acetyl cysteine (NAC) is a sulfur-containing compound that powerfully supports natural intracellular antioxidant systems, particularly glutathione. That makes it an effective radioprotective agent.72 NAC attenuates liver damage from radiation in mice, reducing oxidant damage and resultant DNA damage—both before and even after radiation exposure.73,74 By a separate mechanism (multitargeting again), NAC stimulates release of cytokines known to protect bone marrow against radiation injury.75 And NAC protects bone marrow cells from radiation as well, largely by preventing DNA damage.76,77 A multi-supplement mixture including vitamins C and E plus NAC significantly increased 30-day survival of mice exposed to a potentially lethal dose of X-rays.78 Remarkably, the effect was the same whether the supplement was given before or after the exposure.