Could Small Amounts of Radiation Be Good For You? It’s Complicated.

By David Warmflash | April 6, 2015 11:07 am

operating room radiation

Exposure to high levels of ionizing radiation is extremely bad for human health. Witness the effects of acute radiation sickness suffered by early scientists studying radioactive elements, or by survivors of atomic bomb blasts. Witness the complex procedures through which doctors must shield cancer patients from radiation therapy, and the long-term complications of adult survivors of cancer who were treated with earlier technology. In light of all this, it’s clear that high doses of ionizing radiation are dangerous.

But the science is less clear when it comes to low dose radiation (LDR). Medical science, the nuclear industry, and government regulatory agencies generally take a play-it-safe approach when considering LDR. In recent years, however, an increasing number of researchers (though still firmly in the minority) have questioned the assumption that all radiation is bad – and have begun studying whether low doses might in fact aid in genetic repair, prevent tissue damage, and other benefits.

Doing the Math

The health effects of low-level radiation are based on a mathematical assessment called the linear no-threshold model. The model essentially uses math to extrapolate the effects of low doses from observed effects at high doses.

Using data from populations exposed to moderate to high levels of ionizing radiation – particularly those in Hiroshima and Nagasaki, Japan, at the end of Word War II – scientists have plotted a graph of radiation dose versus various diseases.

As expected, the trend shows that cancer risk increases in proportion to radiation dose. In the linear no-threshold model, the line then is extrapolated backwards to generate theoretical risks for those exposed to much lower doses of radiation.

In other words, the model assumes that if a lot of radiation causes a lot of cancer and a medium amount of radiation causes some cancer, then LDR must cause a little bit of cancer. Or put differently, there is no threshold below which the risk for developing cancer does not increase at all.

This assumption has been in place for decades, for various reasons. Toxicologists have focused principally on high-dose effects, writes Edward Calabrese, because those were the most clearly harmful. Studying the subtle effects of low-dose radiation would have required much larger and more rigorous studies that were less obviously needed to protect public health.

Evidence for Hormesis

However, evidence that’s been trickling in since the nuclear age suggests that LDR could actually benefit human health. In other words, not only is there a threshold for radiation exposure – a limit below which radiation should not be harmful– but at certain low levels ionizing radiation may do more good for your cells than harm. The idea that a low dose of a bad thing can have good effects is called hormesis.

Other so-called hormetic effects in humans are well documented. At low levels, and in certain circumstances, physical stressors such as exercise, cold, toxins, and fasting all bring health benefits. These appear to work by slightly over-activating the body’s repair machinery, relative to a small stress, with net positive results.

Research on radiation hormesis, specifically, has a long history. A review of studies published before 1940 found evidence of radiation hormesis across a striking number of species of plants, fungi, protozoans, algae and insects. In people, during the first half of the 20th century LDR was used to treat pneumonia and certain other medical conditions. The practice ceased as both the public and medical professionals grew more cautious about potential long-term effects of radiation, especially cancer.

Image by Olivier Le Moal/ Shutterstock

Image by Olivier Le Moal/ Shutterstock

Current Research

But since the turn of the current century, researchers have been reexamining radiation hormesis, applying LDR treatment in various disease settings in laboratory animals.

Various studies in mice have found that exposure to low-dose radiation protects against the effects of subsequent exposure to mid-lethal doses of X-rays, minimizing DNA damage and mortality.

A similar effect has been observed when the radiation is received in utero. Exposure of pregnant mice to “Chernobyl radiation” (doses and types of radiation encountered by the bulk of humans living near the site of the 1986 nuclear accident), did not harm the newborn mice. And the researchers found that later doses of radiation did less harm to the mice’s DNA health and levels of white blood cells than were seen in untreated mice.

Within the last few years, LDR has shown promise in combating the complications of diabetes. Studies have found that diabetic rats show faster wound healing when dosed with low levels of radiation. And other rodent experiments have found that radiation at very low doses can prevent kidney damage, one of the most common long-term complications of diabetes.

Studies like these suggest that the linear no-threshold model may be wrong – that there may exist doses, above the normal background radiation and below the threshold for harmful effects, that can actually provide health benefits.

Why Radiation Might Be Good

Normally, we receive a small amount of background radiation from space and from Earth itself. Normal cell repair mechanisms have evolved to compensate for this. Cell enzyme systems repair damaged membranes and mutated DNA.

LDR entails a level of exposure slightly above the normal background. Researchers theorize that LDR might accomplish its benefits by amping up cells’ inbuilt mechanisms for self-repair. The result, it appears, is defenses that outstrip the threat, leaving organisms more protected against various diseases than if they’d had no radiation treatment.

The topic of radiation hormesis is especially relevant given the ongoing debate among medical professionals about whether low- to mid-level X-radiation from CT scans is harmful to patients. But it remains controversial.

What’s more, it’s a complicated topic. The optimal dose of radiation for any person probably depends on a plethora of factors including genetics, age, and even a person’s lifestyle. And even for the same person, the optimal dose of LDR might differ for one health condition versus another.

That makes radiation a complicated medical topic, and may explain why you don’t often hear its possible upsides more widely discussed. However, in the scientific literature, studies related to radiation hormesis have steadily increased in number over the last three decades.


Data from Medline Trend. Graph by Discover staff

Radiation in Medicine

Some researchers have begun trying to examine low-level radiation effects in human populations. One recent study, for instance, found that lung cancer incidence is significantly lower in U.S. states where nuclear testing occurred or where uranium was mined.

The larger medical community, however, remains unconvinced. A 2006 review by the National Academy of Sciences considered a wide range of studies but concluded that evidence for radiation hormesis in humans was too thin to prove its existence. It pointed out that, although benefits of LDR were indeed reported in some studies, the downsides weren’t fully accounted for – things like gene mutations, cell death, or cancer many years later.

For instance, in experiments on low-dose radiation given to dogs over the course of their lifetimes, though the dogs showed increased DNA repair and cell proliferation, they also had higher rates of leukemia. “It is unclear whether such competing events would result in a net gain, net loss, or no change in health status,” the authors write.

There is a long way to go to in research on low levels of radiation before understanding its risks and benefits. The next steps probably involve more studies on how mammals, such as dogs, pigs, or possibly non-human primates, respond to varying amounts of LDR during fetal life and at different ages, and then testing their ability to resist the onset of diseases compared with animals that did not receive LDR.

Answers, when they do come, could reveal some important things about the development of diseases such as cancer, and how our bodies’ repair mechanisms fight them off.


Top image by VILevi/ Shutterstock

CATEGORIZED UNDER: Health & Medicine, Top Posts
MORE ABOUT: cancer, personal health
  • A Cat


  • Uncle Al

    Fukushima’s multiple-Chernoble dump has arrived at the US West Coast via Kuroshio to North Pacific to Alaska and California currents. Kelp has crickets and seals are burning as fission waste concentrates up the food chain. Chernobyl, its forests and animals look OK, right?

    Maybe it’s all about removing people rather than adding radiation.

    • Rappy

      You’re sentences makes very little sense. Particularly if you actually research a little deeper than apocalyptic doomsaying websites. So let’s break it down. What have you read about Seals?

      • Uncle Al

        I live in Southern California, I own a TERRA-P Geiger counter and integrating dosimeter. Collect, oven dry, crush kelp. Remove the rear lead shield from the TERRA-P and snug it in there. 24 hours of background is not 24 hours in the sample. (Cloisonné decoration can be very hot for its uranium glazes.)

        Asstronaughts in ISS FUBAR integrate a nice dose inside the magnetosphere but above the yard of lead-equivalent atmosphere (1033 g/cm^2). Even NASA admits a 90% incidence of radiation cataracts. Do those personnel live better, or folks living in Denver, CO (1610 m altitude) or Quito, Columbia (2800 m altitude), or Nagqu, Tibet (4436 m altitude)? The experiment has been done, rodents to people. One need only look. Empiricism is the bane of social activism, whose singular goal is intent.

        • Martin Kral

          This is a perfect example of the use of a true fact to
          lead a scientifically and mathematically ignorant public to a false conclusion.

          • Uncle Al

            Tell us your “true” conclusion.

          • Martin Kral

            You didn’t answer Rappy’s only question. “What have you read about Seals?”

            You used a diversion. For example:

            Dihydrogen monoxide is also known as hydroxyl acid, and is the major component of acid rain and also contributes to the “greenhouse effect”.

          • Uncle Al

            You have no “true” conclusion. You know nothing about spectral absorption saturation, failure of Beer’s law above A = 2, or how to debate.

            The plural of “anecdote” is not “data,” data are not information, information is not understanding.

          • alqpr

            How did this get to be a CO2=climate debate?
            But rather than change the subject why don’t you tell us what you have actually found or read about seals and give a bit more detail about the actual results of your experiments with kelp?

        • alqpr

          Al, I hope your science is better informed than your geography! But does experience from the high rate ionizing dose for astronauts necessarily tell us much about the effects of the corresponding dose spread over a longer period? And for any epidemiological results about cataracts in high altitude communities how does one de-confound the effects of uv and ionizing radiation?

  • Roya66 tech

    I am an industrial radiographer. I have been exposed daily to low doses of ionizing radiation for close to 28 years & counting. I have thought for years that there may be some benefits as a side effect. I experience sickness rarely & my healing abilities from injuries seems very fast at times. Time will tell meanwhile I still have to earn a living such is life.

    • John_ONeill

      A long term study comparing life expectancy of radiographers in Britain, compared to other medical workers, showed higher mortality till the 1920s ( when exposure levels were much greater than now ), but comparatively lower mortality, from all causes, since. You should be OK. ( It could be that Marie Curie was also a victim of cavalier early x-ray practices. Her and her husband were exposed to fairly high levels of radiation during their long effort to refine radium from pitchblende, but Mme Curie also worked as a radiographer behind the front lines in World War I.)

      • Night-Gaunt

        And I would assume radiographers wear lead lined materials and are not in the room when they use the machines.


    Radiation did wonders for Dr. David Banner, they made several movies and a TV series about his experiences starring Bill Bixby and others.

    • Mike Richardson

      Except he got a really high dose of gamma radiation, which gave him the ability to spontaneously add muscle mass without eating anything — that always bothered me. I mean, where’s the extra mass coming from? Is the green color a clue, that maybe he’s just photosenthesizing at an extremely rapid rate, incorporating carbon from the atmosphere to grow? But anyways, the Incredible Hulk was much more interesting than a more realistic approach to gamma radiation poisoning, such as the Incredibly Sick and Dying Man.

      • Dan

        A better question is why his shirt would get shredded and torn off but his pants wouldn’t

        • Mike Richardson

          Either the foresight to wear spandex, or censors. You pick.

          • Dan

            Spandex, definitely the spandex.

          • robi sen


      • nucalbrt

        I like the green color and photosynthesis theory.

    • Otto Parts

      Ra-di-a-tion. Yes, indeed. You hear the most outrageous lies about it.
      Half-baked goggle-box do-gooders telling everybody it’s bad for you.
      Pernicious nonsense. Everybody could stand a hundred chest X-rays a
      year. They ought to have them, too.

      • John Tjostem

        e Discover article was in general supportive of low dose
        radiation. It was not well researched.The biological mechanism for the
        hormetic effect which is a multifaceted adaptive immune response was not
        developed. Also there are convincing human studies (100 year
        radiologists study, the shipyard study, the chemical explosion in the
        eastern Urals that vaporized a tank of radioactive material, the Cobalt
        60 in the Taiwan apartments, and the watch dial painters all present a strong case for the benefits of low to medium dose

    • ubik

      Don’t forget the radiation that changed a spider that changed Peter Parker’s life (comic book world, not dorky Tobey movie world).

  • Kox3

    Contrary to Warmflash’s statement that “the science is less clear when it comes to low dose radiation (LDR)” the science is clear on it. It just that the radiation-medical-military-federal-industrial cartel has long corrupted the raw databases (derived from Hiroshima, Nagasaki, etc.) about low dose ionizing radiation (elaborated on in ‘The Mammogram Myth’ by Rolf Hefti) to hide the serious and high danger from that type of radiation, especially the man-made kind such as medical x-rays or the radioactive material from nuclear reactor industry, etc.. Example, the proven fact is that the lowest possible dose of ionizing radiation is carcinogenic and that the corrupt corporate cartel is responsible for the death of millions of innocent and unwitting people.

    So, Warmflash’s statement that “Medical science, the nuclear industry, and government regulatory agencies generally take a play-it-safe approach when considering LDR” is pure corporate propaganda.

    Hormesis is an ambiguous notion that typically gets seriously distorted and is often wrongly applied to all kinds of things.

    If you look at the actual research data on radiation hormesis you’ll find that low dose radiation has a hormetic effect which is the induction of damage, followed by TEMPORARY BENEFITS (eg better immunity, slows down aging, etc), followed by LONG TERM DAMAGE (eg higher morbidity and mortality).

    Per the theory – or rather, dogma – of hormesis you’re chance of getting lung cancer is reduced if you were to smoke a few cigarettes every day …

    Warmflash makes several other mistakes by, for example, failing to account for different effects of different types of radiation exposure sources. Clearly he has a shallow sense of understanding of the matter, thus disseminating the popular ideology of the corporate culture.

    • B.J.D

      he proven fact is that the lowest possible dose of ionizing radiation is carcinogenic and that the corrupt corporate cartel is responsible for the death of millions of innocent and unwitting people.

      To put it mildly, that statement is bull$hit. There is ZERO epidemiological evidence that low dose radiation is harmful. The decision was made 60 years ago make that link and have safety guidelines reflect that with the introduction of the LNT, but there’s no science to back it up.

      • JLawson

        Looks like a burner Disqus account. Probably worried the radiation-medical-military-federal-industrial cartel will get him for telling the truth.

        • ubik

          We, I mean, they sure will!

    • Sebastian Mai

      i smell conspiracy theorist here

    • jhertzli

      Other than that it’s okay?

    • JohnSkookum

      “serious and high danger from that type of radiation, especially the man-made kind such as medical x-rays or the radioactive material from nuclear reactor industry, etc.”

      Do tell. Is a “natural” photon from a gamma-emitting rock safer than one of the same energy from an X-ray generator or a medical or industrial source of gamma rays? Please explain.

  • jhertzli

    The evidence from lung-cancer statistics is clear: Radiation makes people stop smoking.

    • Kapricorn4

      I read somewhere that tobacco smoke contains radioactive metal particles is what causes lung cancer.

  • James_IIa

    I remember this suggestion of a beneficial effect from radiation from the days of the radon scare, which would have been in the 1980’s. Some of the studies were showing the paradoxical result that people were getting a benefit from low doses of radiation. That memory is consistent with your graph.

    • nucalbrt

      Good point with radon, but wasn’t that more due to internal dose? But it’s disturbing how something that was such a crisis (radon) a decade or so ago is no longer even discussed or mentioned. Government media suppression at its best.

      • James_IIa

        I had to look up “internal dose”! But I think you are right. People thought radon gas did its damage by being inhaled. The more general point is that the regulators adopted the view that if 10 rads causes cancer, then 0.001 rad causes a tiny bit of cancer. However, there’s increasing evidence that exposure to small amounts of some toxins is too minor to cause disease, but gives the body a chance to build up resistance to the toxins. This appears to hold for radiation and some microbes. I doubt it holds for everything.

        • Michael J. McFadden

          “Some” toxins is the key. It’s important to remember that Magic comes into play here. Tobacco is a Magickal Plant: the less tobacco smoke you are exposed to, the more powerful it becomes! If you try to argue against that you’ll immediately be labeled as either “A Big Tobacco Shill” or “An Addict.”

          – MJM

          • James_IIa

            I don’t know whether you were following it at the time, but there were studies of “passive smoking” or “second-hand smoking” a couple decades ago. In most situations you will be getting a minimal dose from second hand smoke, but everyone “knew” it was evil, so the studies were skewed to allow the FDA to declare it harmful.

          • Michael J. McFadden

            OK, we’ll try it this way since there seems to be a problem with live links:

            James, yeah… I was following it. I’ve been fighting the Antismokers and their craziness since the mid 1970s. I’ve even written two books, complete with over a thousand citations, on the subject! :> Click on the Book Selections tab at the main TobakkoNacht dot com site and you’ll see a number of short excerpts that I think you’ll enjoy!

            Oh! It wasn’t the FDA btw: It was the EPA. They announced their results months before they finished the study, excluded major research that contradicted their desired findings, juggled the statistics and STILL couldn’t reach the normally accepted statistical significance level. In any area of REAL science the conclusion would have been “no effect.” Instead they simply pretended that the statistics came out significantly and published their claim saying they’d shown a danger and workplaces needed to ban smoking everywhere! The Report they did was so bad that it was actually thrown out by a federal judge! (Unfortunately, since they’d been careful to make their Report “advisory” and it had no “binding” aspect to it the judge was ruled to have no jurisdiction over its dissemination.)

            – MJM

          • James_IIa

            “It wasn’t the FDA btw: It was the EPA.”

            Thanks for the correction and the rest of the interesting story. To add to the regulatory nightmare, we have two agencies to look into such matters. My recollection is that EPA tends to set much stricter standards than FDA, which is the agency that should have more expertise on human health.

  • ubik

    As life evolved on Earth, the level of radiation exposure was higher than today. It may be that life evolved in an environment of a certain amount of radiation and life adapted to it. At least that’s a theory I have seen.

  • Shannon

    My dad is a plant manager of a radiation company where they use radiation from cobalt-60 to sterilize food, medical equipment and even human tissue used in transplants. It puzzles me that these high levels of radiation can kill a person yet it doesn’t kill the human tissue.


    • Ayala

      Dear Shannon, high dose radiation kills multiplying cells like bone marrow and spermatogonia (the tissue creating new sperms) and of course bacteria. Non proliferating tissue like muscles, fully grown sperms and even the brain are relatively resistant to radiation damage and that’s how your dad’s company can sterilize food and human tissue.

  • MW642243

    Wow. Who would have thought that man could create better photons than nature! What crap are we teaching today? It’s good to see that there are a least a few folks with a healthy perspective on radiation.

  • elidyl

    Do you think author has a vested interest in the issue (“Thorium Power is the Safer Future of Nuclear Energy”)? These questions are reviewed on a regular basis (WHO, UNSCEAR, ICRP, BEIR, and others). There is considerable uncertainty in the low dose range, which the author and others are very good at using to their advantage. The issue is what to do in response to this, should we prudent in light of this uncertainty, and who gets to decide.

    Does the author think the scientific bodies mentioned above are insufficient or unqualified to decide the matter? If so, what is the alternative? This debate always sounds to me to be inspired in kind by the push for deregulation in any industry (finance, environmental pollution, labor standards, consumer product safety, etc.). That somehow, the only way to create a viable and commercially successful energy business is with lower standards and less regulation. We really can’t think of anything better. Our collective experience over the last 100 years fighting tooth and nail with corporate and special interests (particularly with extraction industries, environmental polluters, and more), and achieving real and tangible gains for the public interest, doesn’t teach us better. Yes, we have some productive areas of new research in this area, much of it lab based, but to go so far as to say low dose radiation is “healthful” and a benefit to public safety, is a stretch, and does little to improve public confidence on the matter (educated or otherwise). In fact, it probably does the opposite. Especially when such science, uncertain as it is, is misapplied and misconstrued by active and special interests actively campaigning on the matter.

  • Michael J. McFadden

    A very interesting concept with regard to exposure implications for secondary tobacco smoke. Back in the late 90s the antismoking world was holding its breath awaiting the results of the supposedly “definitive” international case-control study on ETS and lung cancer being carried out by the World Health Organization. (Journal Of The National Cancer Institute, Vol 90, 1440-1450, “Multicenter case-control study of exposure to environmental tobacco smoke and lung cancer in Europe.”)

    Unfortunately for the Antismokers the study managed to come up with only ONE “definitive” finding at the 95% Confidence Level. That finding was that children of smokers got 22% LESS lung cancer as adults than children of nonsmokers!

    Of course the hormetic argument wasn’t even considered in that particular political bombshell. The authors were so embarrassed by their findings that, even though that was their only real discovery, they described it, wrongly, in the Abstract as showing “no association” !!!

    Amazing, eh?

    – MJM

    • Lucina Meyers

      Sounds like a lot of rationalization by those wanting to continue to smoke. There is no question today that smoking affects all body systems, your life expectancy. But go ahead. I just don’t like it when these non-facts are made public. You can hurt a lot of people.

  • Jane Peters

    I’d rather not be exposed to any radiation whatsoever. And I’d rather not my animals or plants either. Mutations are not a good thing.

    • Thomas Ijon Tichy

      “Mutations are not a good thing.”

      In other words, you are not a good thing.

  • Alexander Rawls

    Hormesis is a universal phenomenon. Any stressor, in low enough doses, has a stimulative-positive health effect. Good for EPA for finally recognizing the non-harmful, even beneficial, effects of low dose radiation, but they need to do the same with other toxins.

    Obama used anti-Mercury regulations to shut down the coal industry when the very low mercury exposures from modern coal burning are KNOWN to fall well within the hormetic range, making them beneficial, not harmful.

    No more linear extrapolation to zero anywhere ever except regarding importation of new disease vectors and invasive species (where not having to face a threat at all is better than having a marginally better ability to fight a threat that comes at the expense of HAVING to fight it).


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