Doss Report #1: The Deadly DNA Damage
Having noted the phenomenal rise in the popularity of Stephen Colbert after he embraced his opposition's conservative philosophy, I have decided to abandon my support for adaptive protection in my previous publications (please see http://goo.gl/Lzsmx, http
Following the change in my philosophy, the US EPA's recently released FGR-14 http://www.epa.gov/radiation/federal/fgr-14.html (Radiation Protection Guidance for Diagnostic and Interventional X-Ray Procedures) makes a lot of sense. The justification for the FGR-14 document is explained in lines 71-76 of the Preface: "Concerns continue to be raised about the risks associated with patients’ exposure to radiation from medical imaging (Amis et al. 2007; FDA 2010b; FDA 2012e). Because ionizing radiation can cause damage to DNA, exposure may increase a person’s lifetime risk of developing cancer. Although the risk to an individual from a single exam may not itself be large, millions of exams are performed each year, making radiation exposure from medical imaging an important public health issue (Brenner 2007)." The task group at EPA has reviewed a large number of actions recently recommended by many national and international experts and professional organizations because of such concerns, and has developed this comprehensive impressive guidance document based on the well-accepted principle of as low as reasonably achievable (ALARA). In view of their expertise and experience in this field, I would like to suggest EPA should consider guiding the President in a few more areas that may be causing increased DNA damage that have been largely ignored so far, in order to further improve human health. These areas are ripe for immediate action since new publications have appeared recently raising health concerns from the increased DNA damage. Thus, avoiding DNA damage from medical imaging is not sufficient. We have to avoid DNA damage from other sources too because of the clearly established link between DNA damage and many deadly diseases such as cancer and Alzheimer's disease.
The first area of concern is the increased DNA damage that has been reported from even five minutes of strenuous exercise (70% VO2max) in the article "Exercise-induced lipid peroxidation: Implications for deoxyribonucleic acid damage and systemic free radical generation"
In the article the authors say (near the bottom of page 40) "Regardless of the mechanism(s) of exercise-induced DNA damage the fact that a very short bout of high-intensity exercise can cause an increase in damage to DNA is a cause for concern". Though there was no increased DNA damage observed at 40% VO2max by the authors (Fig 2), in analogy with statements from radiation experts, the non-observance of DNA damage from the non-strenuous exercise does not imply the damage is not there, in particular since PBN adducts and serum LOOH do appear to show a linear response indicating the action of free radicals and the presence of oxidative damage from non-strenuous exercise (Figs 3 and 4). Therefore, caution is advised for non-strenuous exercise also, assuming a conservative linear no-threshold relationship, as for radiation. In view of this, the increasing number of profit-motivated fitness centers that have sprouted all over the country in the past few decades are a major cause of concern, and especially the increase in the number of personal trainers employed therein, who are known to force their paying, unwilling, and unwitting clients into strenuous exercise regimens increasing their DNA damage. Even the non-strenuous use of the fitness center is of major concern. Although the DNA damage caused in a single non-strenuous use of the fitness center may not be large, millions use the fitness centers everyday, making the DNA damage from the fitness centers an important public health issue. FDA should be asked to declare exercise as a carcinogen (just like radiation) and regulate exercise equipment. The use of the fitness centers and in particular the work of the personal trainers should be strictly regulated to reduce the risk of DNA damage, adapting the principles derived from radiation safety experience, for example, changing ALARA to as little exercise as desired (ALEAD).
A second area of concern is the increased DNA damage of the more deadly kind, the difficult to repair DNA double-strand breaks (DSBs), that have been reported in brain from neuronal activity, i.e. thinking, and especially learning in the article "Physiologic brain activity causes DNA DSBs in neurons, with exacerbation by amyloid-β"
http://www.nature.com/neuro/journal/v16/n5/full/nn.3356.html
http://www.nature.com/neuro/journal/v16/n5/full/nn.3356.html
Though the authors have labeled the learning related DSB's as transient, since the DNA repair process is known to be not perfect (thanks to radiation experts), some of these damages are bound to accumulate, raising concerns regarding the increasingly freely available popular learning activities e.g. free classes by Ivy League schools, Khan Academy, etc. It is alarming that increasingly even preschoolers are being forced to learn by proposed government mandates. Although the amount of learning-related DSBs generated everyday in a student’s brain may not be large, millions of students are attending schools and colleges everyday, making DSBs from learning an important public health issue.
The authors have also reported that the DNA damage is exacerbated by the presence of amyloid β (Aβ) proteins. Since the Aβ proteins are known to accumulate with age in the brain, the consequent increased DNA damage in adults from new learning represents a serious and growing problem in the aging population. The authors have stated near the bottom of page 6 of the article: "Pathologically elevated Aβ increased neuronal DSBs at baseline and augmented and prolonged the increases in DSBs that resulted from physiological increases in neuronal activity. It is tempting to speculate that these Aβ effects could ultimately threaten the stability of the neuronal genome and interfere with the fine regulation of gene expression required for cognitive functions." Please don't think too hard trying to understand the above two sentences. They say, in simple terms, learning in elderly can be hazardous to their brain function. In view of this, the increasing numbers of universities that encourage neuronal activity from learning in the elderly are a major concern. In a recent disturbing trend, many elderly are returning to colleges and even high schools after retirement, likely increasing DSBs in the brain and contributing to the development of Alzheimer's disease. The surgeon-general should be asked to declare learning as hazardous to brain health, especially in elderly, and such warning should be required to be posted prominently in all schools, colleges, and learning websites, and in all of their advertisements and brochures. Since our constitution guarantees freedom of thought and expression, and since thinking, that is turning out to be hazardous, cannot be banned until the constitution is amended, deep thinking should be discouraged, and thoughtless actions should be encouraged through public service messages by the government. Again, the principle of ALARA should be adapted to as little thinking as needed (ALTAN).
Base on these major concerns due to increased DNA damage, please join me in my appeal to EPA: Please give serious consideration to the above ideas, and take appropriate actions. On cursory second thought (I am being cautious now, with cursory thinking, as you can see), in view of the hazards to your brains from such serious considerations, please give little consideration to the above ideas, and implement these suggestions thoughtlessly, setting an example for the masses. Hope you don't mind me writing this thoughtless e-mail to you, but I am interested in preserving my brain health and also in helping others to do the same.
Sincerely,
Duh
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Take-home Message from Doss Report # 1:
You all probably know that regular exercise reduces the chance of having cancer. You all probably also know that regular brain stimulating activity like playing bridge or solving puzzles in the elderly reduces the chance of having Alzheimer’s disease. Why did we come to completely opposite conclusions in the thoughtless discussions in “Doss Report #1 – The Deadly DNA Damage?”
Well, the analysis ignored one key aspect of our body, i.e. that our body is alive, and so is not inert, but responds to the hazards that it notices, for example DNA damage. This protective, defensive response is called adaptive protection. The defense includes increased DNA repair enzymes, enhanced immune system response, etc. These higher levels of defenses last for several hours or days or weeks and so there would be less damage to the body during this time period when compared to the natural damage that would have occurred if the defenses were not elevated. What is the final result? Even though activities like exercise and brain activities cause some DNA damage, the net result over the long period of time is that there is much less DNA damage because of the stimulated defenses (in comparison to no exercise and little stimulating brain activity), and so there is improved health.
Now, let us consider radiation. The effect of a small amount of radiation is to cause a small amount of DNA (and other) damage, but that damage stimulates the defenses in the body just like exercise and brain activity do. As a result, low dose radiation can be good for our health, and can result in fewer cancers, and can also reduce many of the aging-related diseases, including Alzheimer’s disease. This beneficial effect of radiation is called radiation hormesis, and was proposed more than thirty years ago by Prof T D Luckey in his book, ‘Hormesis with Ionizing Radiation’. There is plenty of evidence in animal studies for reduction of cancers and many aging-related diseases including brain diseases using low dose radiation, but the current superstition that low dose radiation is dangerous has prevented study of these ideas in humans to see if they work. I am hoping at least some of you among the general public become convinced of the view that a small amount of DNA damage is not something to be scared of, as it can have beneficial effects, as seen for exercise and for brain activity.
Please let me know if I have made sense to you, by taking the short survey at: https://www.surveymonkey.com/
Mohan Doss, Ph.D., MCCPM
Medical PhysicistFollow me on Twitter at: http://twitter.com/DossReport
Copyright Ó 2013 - Mohan Doss
