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Cell Phones And The Brain
John D. MacArthur is a freelance writer specializing in neuroscience. In 2001, The Franklin Institute Science Museum commissioned him to research and write a comprehensive online section about the human brain. This article was published in the July 2002 issue of the Townsend Letter for Doctors & Patients.
During the past century, electricity has become the driving force of civilization, yet much mystery still surrounds this primal energy. We don't really know to what extent biological processes are influenced by the electromagnetic fields that emanate from everything electrical -- especially the long-term effects on our extraordinarily complex and sensitive brains.
The most immediate concern involves the safety of cellular (mobile) telephones. Conflicting studies and conflicts of interest have led to considerable controversy, but some progress toward a realistic analysis of cell phone safety was finally made with the publication of a major British report -- the most thorough yet undertaken.
Adopting an evidence-based approach, the government-appointed Independent Expert Group on Mobile Phones conducted "a rigorous assessment of existing research." For eight months the panel of 12 scientists consulted widely and heard evidence from experts, members of the public, representatives of government, interest groups, and the industry. On May 11, 2000, the Expert Group presented its report on Mobile Phones and Health. (1)
Key findings include:
"We conclude therefore that it is not possible at present to say that exposure to RF radiation, even at levels below national guidelines, is totally without potential adverse health effects. "We recommend that a precautionary approach to the use of mobile phone technologies be adopted until much more detailed and scientifically robust information on any health effects becomes available . . . These should include the following: effects on brain function, consequences of exposures to pulsed signals, . . . the possible impact on health of sub-cellular and cellular changes induced by RF radiation . . .
"Children may be more vulnerable because of their developing nervous system, the greater absorption of energy in the tissues of the head, and a longer lifetime of exposure . . . We believe that the widespread use of mobile phones by children for non-essential calls should be discouraged.
Important new findings about the electrical nature of the brain and DNA are discussed. Also mentioned are several recent studies that may represent pieces to the neurodegeneration puzzle. Current safety guidelines for cell phones assume no harmful effects as long as the microwave radiation they emit does not cause heating of body tissue. Exposure limits are intended to protect us only from excessive temperatures caused by absorption of energy -- a known danger linked to the intensity of radiofrequency microwaves.
But intensity and temperature are not the
only considerations. Living cells also respond in non-thermal
HOW ELECTRICITY AFFECTS BIOLOGY
Electromagnetic Fields and Free
The magnetic field component of an external EMF can delay this "recombination rate" of free radical pairs. In other words, magnetic fields cause radicals to stay free longer. Although measured in nanoseconds, this extra time gives them the potential to do more damage.
Ongoing research by a team of chemists at the University of Ottawa has shown that magnetic fields increase the average concentration of free radicals, lengthen their lifetime, and enhance the probability of radical reactions with cellular components. (2)
Although free radicals are a normal part of metabolism and play a vital role in many biochemical processes, the body must keep them under control. An increase in free radicals can affect various cellular and physiological processes, including gene expression, release of calcium from intracellular storage sites, cell growth, and cell death. The actual effects, however, can vary from individual to individual and may depend on one's nutritional status and the availability of dietary antioxidants.
A major study involving 3,385 Japanese-American men from the Honolulu-Asia Aging Study reinforces the value of antioxidants for the brain. Elderly men who took both vitamin C and E supplements had an 88% reduction in the frequency of vascular dementia, compared with men who did not take the supplements. The protective effect was substantially greater in men who reported long-term use of both vitamins.
Regarding the mechanism of the protective effect, Dr. Kamal H. Masaki, of the Honolulu Heart Program, and co-authors say that the study results support "hypothesized roles for cellular and molecular oxidative injury in the pathogenesis of brain aging and neurodegenerative diseases, including Alzheimer's dementia and Parkinson's dementia, and vascular dementia." (3)
EMFs and DNA
The researchers then found that this EMF-induced DNA damage could be blocked by treating the rats with antioxidants, including melatonin, immediately before and after exposure. Melatonin is a hormone secreted from the brain's pineal gland. As a potent antioxidant, it effectively eliminates free radicals inside cells -- suggesting that free radicals may play a role in the genetic damage caused by magnetic fields. (4,5)
The effect of radiofrequency radiation on DNA could conceivably be more significant on neurons than on other cell types, because these nerve cells have a low capability for DNA repair, says Dr. Lai. "Since nerve cells do not divide and are not likely to become cancerous, more likely consequences of DNA damage in nerve cells are changes in functions and cell death, which could either lead to or accelerate the development of neurodegenerative diseases." (Glial cells, however, can become cancerous. These more numerous brain cells protect and support neurons.) (6)
Dr. Lai cautions against applying the existing research results to evaluate the possible health effects of normal cell phone usage. While "it is difficult to deny that radiofrequency at low intensity can affect the nervous system," he says the data available suggest a complex reaction. Other parameters of exposure, "such as frequency, duration, waveform, frequency- and amplitude-modulation, etc., are important determinants of biological responses." More research is needed, but since not much is known on the biological effects of cell phones, "prudent usage should be taken as a logical guideline."( 6)
Past research has demonstrated a correlation between EMFs and decreased levels of melatonin in the body, but results have been inconsistent. Numerous factors are involved, including one's natural melatonin levels and the length of exposure. A recent study suggests there may be a"cumulative effect of magnetic field exposure on the stability of individual melatonin measurements over time." (8)
EMFs are characterized by many variables, such as the orientation of the magnetic field and its polarity. In a study of electric utility workers, Dr. Jim Burch of Colorado State University has shown that certain EMF environments have a greater effect on melatonin levels. The key difference may be the polarization of the magnetic field.(9) Burch's preliminary results agree with a series of animal studies by Dr. Masamichi Kato at Hokkaido University School of Medicine, Sapporo, Japan.(10)
DNA Conducts Electricity
"It's not at all like a conductor or a wire," said lead author Dr. Gary B. Schuster. He compared the charge transport mechanism to the movement of a Slinky, the large spring used as a toy. When an electrical charge is injected into DNA, the DNA responds by changing its structure to pairs. This creates a local distortion that, just like the compression in a Slinky, can move in the DNA. The charge transfer stops when it encounters a specific pairing of two chemical bases (guanine), where it then oxidizes the guanine and causes strand breaks that can lead to genetic mutations. (11) Normally, DNA is capable of efficiently repairing itself. Through a homeostatic mechanism, cells maintain a delicate balance between spontaneous and induced DNA damage. By causing an increase in free radicals, however, EMFs may alter this balance.
Cell Division Errors and Aging
"This study suggests that aging is really a disease of quality control. In this case the manufactured product is a new cell," says co-author Richard A. Lerner, M.D., president of The Scripps Research Institute. While the research is not conclusive, Lerner says the process begins slowly in middle age and gradually accelerates as we get older. In tissues throughout the body, an increase in cell division errors leads to altered gene expression which causes the loss of tissue function -- culminating in the diseases and conditions associated with human aging. (12)
In 1999, Swedish researchers exposed mice
to EMFs generated by actual outdoor electric transmission power lines (220
kV). After 32 days of exposure, a highly significant change was observed in
the animals' brain cells. The researchers said their "data indicate that
transmission lines of this type may induce genotoxic effects in mice, seen
as changes in the DNA migration."(13)
The Scripps study also revealed links to specific age-related disorders. In Alzheimer's disease, there was evidence for the overexpression of a small protein associated with heat shock. Other studies have confirmed the presence of alpha B-crystallin and other heat shock proteins in the brains of patients with Alzheimer's as well as in those with Parkinson's disease. Furthermore, the myelin-producing cells (oligodendrocytes) were among those most affected. (14-17)
Swedish researchers at the University of Goteborg have shown an association between Alzheimer's disease and altered lipid composition in myelin, indicating that demyelination is a primary event in late-onset form Alzheimer's disease. (18-19)
In a significant new study titled "Cell
biology: Non-thermal heat-shock response to microwaves," worms were
continuously exposed to microwave radiation of the sort emitted by cell
phones. The researchers showed "that prolonged exposure to low-intensity
microwave fields can induce heat-shock responses in the soil nematode
Caenorhabditis elegans. This effect appears to be non-thermal, suggesting
that current exposure limits set for microwave equipment may need to be
Keeping brain cells from overheating is one of the bloodstream's functions. Blood not only delivers oxygen, glucose, and nutrients, and removes toxins; it also cools the brain. An efficient cerebral vascular system enabled the evolution of intelligence, and healthy blood vessels continue to be necessary for proper cognitive function -- and for protection against neurodegenerative diseases -- especially since both "epidemiologic and pathologic observations suggest that vascular factors may contribute to the development of Alzheimer's disease." (21)
The summer 1999 heat wave in the Midwest reveale d another piece to the neurological health puzzle. The U.S. Centers for Disease Control found that psychiatric medicines could make the mentally ill especially vulnerable to death from intense summer heat. This is because antidepressants that target the brain can interfere with the body's thermoregulatory system. (22)
Heat Stress from EMFs
This thermal threshold is itself problematical, because it is based on the body's ability to maintain homeostasis during heating from the radiofrequency radiation. But even if the body's thermoregulatory mechanism succeeds in distributing the heat and maintaining the temperature at the pre-irradiation value, a certain stress still develops.
A pioneer in the bioeffects of electromagnetic fields, Robert O. Becker, M.D., emphasizes the role of EMFs in producing stress. In his landmark 1990 book, Cross Currents: The Perils of Electropollution; The Promise of Electromedicine, he points out that exposure to any abnormal electromagnetic field produces a stress response. After prolonged exposure, the body's stress response system can be exhausted and the immune system compromised. In such a state, animals and humans could become more susceptible to cancer and infectious diseases.
Dr. Becker refers to experiments conducted in the early 1980s by the U.S. Air Force School of Aerospace Medicine that were reported in the September 1986 issue of Scientific American. Test animals were continuously exposed for long periods to microwaves at a power density twenty times lower than the safe thermal level. They developed a fourfold increase in cancers of the pituitary, thyroid, and adrenal glands -- the primary organs through which the body mediates stress.
The cellular stress response is a protective mechanism that enables cells to survive. It is activated by a wide variety of environmental stimuli, such as high temperature, oxygen starvation, and heavy metals, as well as EMFs. Cells essentially perceive man-made electromagnetic fields as potentially harmful.
Thermal vs. Non-Thermal Stress Response
To provide a more realistic basis for new cell phone safety standards, Goodman and Blank have recently focused on the bioeffects of radiofrequency radiation. They discovered remarkable similarities in the biological responses to both the low and the high frequency fields emanating from cell phones. What's more, preliminary results showed that "the energy required to induce stress proteins with low frequency EM fields is 14 orders of magnitude lower than required by temperature increase." (24)
Not only did they find it possible to differentiate between thermal and non-thermal stress, but the stress proteins induced by low frequency served as "biomarkers" to monitor the early stages of the cellular stress reaction to EMFs -- prior to activation by increased temperature. They believe this will make it is possible to establish a lower, more accurate safety threshold for cell phones and towers.
Electromagnetic Fields and Enzymes
Scientists are learning more and more about intracellular communication pathways. Signals originating at the cell membrane initiate a production sequence of enzyme "cascades" within the cell. These signaling pathways are proving to be sensitive to weak EMFs. (27,28)
In his summary of "Cell and Molecular Biology Associated with Radiation Fields of Mobile Telephones," longtime EMF researcher Dr. W. Ross Adey writes: "Microwave bioeffects at the cellular level support concepts of athermal responses not mediated by tissue heating. A spectrum of these biological responses show dependence on ELF amplitude- or pulse-modulation of the imposed fields. Cell membranes have been identified as the site of transduction of many of these responses, with initiation of enzyme cascades that chemically couple cell surface radiofrequency signals to intracellular systems, including some that reach cell nuclei and regulate processes of cell growth and division." (29)
In the process of programmed-cell-death, caspase enzymes are unleashed to destroy cells that are abnormal or are no longer needed. In Lou Gehrig's disease (ALS), scientists believe the process of caspase-mediated apoptosis is misdirected and begins to destroy neurons. (30)
Researchers at Howard Hughes Medical Institute and at Harvard Medical School have identified an enzyme that may be involved in the pathogenesis of Alzheimer's disease. Calpain, a calcium-dependent cysteine protease, appears to be a common mechanistic link between the death of primary cortical neurons and known causes of neurotoxic damage, including oxidative stress, excitotoxic chemicals, and oxygen starvation. (31)
Enzymes and Free Radicals
Much of this intracellular signaling is mediated by free radicals. Like so many processes, enzyme kinetics re also affected by radical pair recombination rates. Research conducted at Stanford University's Department of Radiation Oncology suggests that although a magnetic field may induce only a very small change in radical pair recombination rate, "the effect on the enzyme reaction rate is considerably larger, for example, by a factor of 1 to 100." (34)
Related research by chemists at the University of Utah found that a decrease in the activity of a vitamin B12-dependent enzyme was likely caused by an applied magnetic field which changed the behavior of free radical pairs. (35)
OUR ELECTRICAL BRAIN AND ENVIRONMENT
Inhibitory Neurons Use Electrical
According to neuroscience professor Barry Connors, electrical synapses may allow these neurons to generate activity over a large area of the brain. They may be acting as the brain's "pacemaker" by creating some of the brain's rhythmic electrical activity, which can be measured by an electroencephalogram (EEG).
Inhibitory neurons prevent the brain from quickly spinning out of control into hyperexcited states. Their malfunction is involved in autism and ADHD, as well as in memory disorders, neural trauma, and addictions. They also play a role in a wide range of psychiatric conditions, such as depression, obsessive-compulsive disorders, and schizophrenia.
This electric neural network is especially suited to regulating higher brain functions, explains Connors. "Most of the time it is not doing anything, but it becomes active when the brain's activity increases to a high level . . . and may act like the governor on the engine of the cortex, keeping excitability from running away and becoming an epileptic seizure." (36)
Researchers at Israel's Weizmann Institute of Science recently discovered that inhibitory neurons are far more diverse than previously thought and have an extremely sophisticated system of controlling other neurons. They build complex synaptic connections onto thousands of neighboring neurons. These synapses then act as fast-switching "if-then" filtering gates which allow inhibition to be selectively applied -- at the exact millisecond and to the right degree. This allows a small group of inhibitory neurons to simultaneously give personal attention to the activity of each of the neurons to which they are connected. (37)
Electrical Rhythms in the Thalamus
Dr. Rodolfo Llinas, a professor of physiology at New York University School of Medicine, has demonstrated that the frequency of brain's electrical system is slower in the thalamus during sleep and much higher when a person is awake. He observed that patients suffering from Parkinson's disease had low frequency oscillations in their brain patterns when awake, instead of the usual high frequency ones. Part of the thalamus' intricate network seemed to be still asleep, causing havoc in the brain's perception of the internal and external environments.
At the October 1999 Society for Neuroscience meeting, Llinas suggested that these abnormal rhythms may be a common thread underlying Parkinson's disease, depression, epilepsy, obsessive-compulsive disorder, chronic pain, and tinnitis. (38)
Our Electromagnetic Environment
Only now are we beginning to realize how a small increase in global temperature can have complex consequences. We know even less about the true repercussions of the unnatural electromagnetic radiation we are creating. This revolutionary modification of a fundamental aspect of life is untested for long-term safety. Furthermore, epidemiological effects of EMFs are difficult to measure, because few control groups exist. (It's interesting to note that the Amish population has a lower prevalence of dementia.). (39)
Despite industry assurances of safety, an increasing number of scientists and citizens are insisting on caution -- the precautionary principle of prudent avoidance -- until we know much more about the bioeffects of EMFs, especially those associated with cell phones and transmission towers.
Cell Phone Legislation
"We think this bill makes a lot of sense," says the executive director of the National Brain Tumor Foundation. "It's just a precautionary measure." Opposing the bill is the Cellular Carriers Association of California, which says the industry was "continuing to look at everything possible to make sure the service was safe."
The editor of Microwave News, Louis Slesin, Ph.D., disagrees, noting that spending on safety research has been ridiculously small. "After all, when a device is pumping radiofrequency/microwave energy into a complex electrical system like the brain, it would seem natural to ask if it changes the way that system works. Instead, no cognitive studies of mobile phones were done until the last couple of years, and none has ever been done in the United States." (40)
In May 2000 SB 1699 was approved by the California Senate. If it becomes law, it will require the State Department of Health Services to conduct a review of existing research concerning the health effects of cellular telephones and to report its findings to the Legislature by July 1, 2001. This bill would also require the Director of Health Services to advise the Legislature regarding the need for additional research and legislative action regarding the use of cellular telephones. (41)
The Scottish Parliament's Transport and the Environment Committee reviewed research into the health effects associated with wireless radiation. They listened to the concerns of communities and individuals across Scotland, as well as reviewed testimonies submitted from other parts of England and the world.
In March 2000, the committee recommended that all telecommunication towers, including cell phone transmission towers, should be required to apply for planning permissions, and local authorities should adopt a precautionary approach:
"Based on the evidence received, the Committee considers that there is reasonable doubt about the health risks and recommends that health should be viewed as a material planning consideration and a precautionary approach should be adopted at a national level allowing for local flexibility. The Committee considers that areas such as schools, nurseries, hospitals, and residential areas may be considered sensitive for environmental health reasons." (42)
The Salzburg Resolution
"Recommendations of specific exposure limits are prone to considerable uncertainties and should be considered preliminary. For the total of all high-frequency irradiation a limit value of 100 mW/m2 (10 µW/cm2) is recommended.
"For preventive public health protection a preliminary guideline level for the sum total of all emissions from ELF pulse modulated high-frequency exposure facilities, such as GSM base stations, of 1 mW/m2 (0.1 µW/cm2) is recommended." 43 [milliwatts per square meter (microwatts per square centimeter)].
The way cell phones are practically given away is reminiscent of how cigarettes were introduced into new markets. Eventually, phones too will probably have to carry warning labels that escalate in severity over the years. And, few people will be surprised if it's ultimately revealed that the telecommunications industry knew more about the negative effects of cell phone usage than they let on.
Today, we view classic films with a mixture of amusement and amazement as movie stars constantly smoke cigarettes in the most inappropriate situations, from baby rooms to bomb shelters. In the future, when we look back at today's media celebration of cell phones, will we cringe at the sight of people holding these powerful electronic devices to their brains?