Scientists Now Seriously
Studying Magnet Therapy
Magnet Therapy
A.R. Liboff
Department of Physics
Oakland University
Rochester, MI 48309
(248) 370-3412
There's a lot of media coverage these days concerning "magnet therapy". For good reason. Annual worldwide sales of such magnets are now reckoned in the billions of dollars. Many everyday folks, (and some physicians) swear by them. They are sold in a wide array of geometries, innersole inserts, flexible pads, small flat buttons, sleeping pads, folding seats, and even stylish bracelets. Most of the claims concerning these magnets refer to their effectiveness in obtaining relief from pain. Rumor has it that President Clinton made use of magnets to help him recover from his leg injury.
The increase in marketability of permanent magnets for pain relief is largely due to the discovery of new, high coercive force materials. Because the larger Hc found in NdFeB and in SmCo allows one to fabricate magnets having less self-demagnetization, very thin geometries are now capable of producing fields of about 0.1 T within a few mm of the pole faces. This means that thinner magnets can be taped to the skin more unobtrusively. Even before the discovery of NdFeB, therapeutic claims were being made for ferrite impregnated plastics, like those used to hold messages on refrigerators. It is a matter of faith and good advertising that the stronger NdFeB magnets are today preferred over ferrites, whose pole strengths are only hundreds of gauss instead of thousands.
New Age Physics
It is difficult for the physics community to deal with things like magnet therapy. Not only are the medical claims somewhat vague, but they are often accompanied by statements about magnetism that are totally wrong. Viewed in context, the magnet craze is really part of our contemporary culture. We may not like it, but a lot of New Age pseudo-science is hyped in mainstream America. Books with strange titles, (some written by respected colleagues), fill the shelves at Border's and Barnes and Noble, each purporting to explain all that quantum stuff, missing cosmological mass, multiple universes, and other assorted mysteries, up to and including God. A thriving pseudo-science subculture has blossomed on the Internet. New Age solutions to pain, disease, personal problems, even investments are explained away in terms of tetrahedral crystals, vortices, potentials, complexity, chaos, simultaneity, and more spins than in Washington politics. Magnets fit beautifully into all of this.
The public apparently likes science, but not at so great a price that one has to be precise. Physics terms take on new meanings, especially some we hold dear to our heart, words like force, energy, and charge. Energy medicine is a good example, encompassing among other things chi, acupuncture, auras, electromagnetism and any other field that happens to be invisible and was hard to understand in college. The physics used in this area is so bad, that paraphrasing Pauli, it's not even wrong. Part of the problem is that healing gurus practicing Energy Medicine feel compelled to reinvent the truth to explain their results. They justify their procedures by masquerading as scientists, borrowing terms willy nilly from physics as needed. They write paperbacks that are found in health-food stores. Many in the energy medicine area add nicely to their income selling such books. Sorry to say, people in pain are more in tune with clinicians who promise to help rather than scientists who tell them why they cannot be helped.
It may be some small consolation to realize that we in the physics community do not come off as the bad guys. Instead, modern medicine is almost universally the villain. According to the New Agers, doctors should know more than they do about the origin and treatment of pain. They contend that the billions spent on research on cancer have not resulted in a cure. There is also profound antagonism against the pharmaceutical industry. This was amply in evidence at a recent meeting I attended featuring a new and promising approach to fight cancer, ECT (for Electrochemical Treatment)[1] where speaker after speaker spoke bitterly about the hazards of chemo- and radiotherapy, each decrying the reluctance of the medical "industry" to seek alternative therapies.
I sometimes think that physics has been so successful in explaining the non- biological world that the public, making the comparison, is asking the medical community: Why can't you be more like them? Even though they don't know much physics, the New Age people want to bring more of it into medicine. In a certain sense, this argument may strike a resonant chord. Medical educators in this country continue to ignore the additional second year of physics that should be required of anyone seeking to enter medical school[2]. None of us should be surprised at how ignorant physicians are about the electromagnetic field.
But on the whole, there is no question about the tawdry history involving the clinical use of magnetism. The most infamous example was that of August Mesmer, immortalized (for the wrong reason) in the transitive verb mesmerize. In fact, today's claims for the healing benefits of simple magnets pale by comparison with those of Mesmer, who "magnetized" not only trees but also young women, usually without the benefit of sources such as currents or other magnets. Two centuries ago, Benjamin Franklin sat on a scientific commission that first examined, and then repudiated Mesmer's claims. This failed to stop the increasingly improper use of electricity and magnetism in medicine in the years that followed[3].
At the turn of the century, the misuse of electromagnetics in medicine had reached the intolerable point where Abraham Flexner, in his seminal Carnegie Foundation report, recommended against any further clinical training based on electricity and magnetism. This antagonism is still around today. Only recently have therapeutic practices based on the use of electricity and magnetism begun to reappear in clinical settings. (The same is not true for non-therapeutic work, where physics has revolutionized diagnostic medicine with devices such as the EEG, EKG, EMG, MRI, and SQUID). The alternative medicine crowd seems to be asking: why does current medical practice depend so heavily on administering pills and drugs? Is there no place for physics in the treatment of the sick?
Lack of Research
My first interaction with the magnet therapy business occurred in the mid- eighties, while attending an APS meeting in Baltimore. A Japanese colleague mentioned that a mattress company was successfully marketing sleeping pads with magnetic inserts to help elderly sufferers from rheumatism and other joint pains sleep more comfortably. He asked how this product could be made acceptable to the US Food and Drug Administration. I outlined the problem to an orthopedic surgeon friend at Harvard, who came up with a proposal to do a double-blind study on the efficacy of these pads. However it soon became apparent that the mattress company was not interested in anyone doing independent research, only in having their own internal reports disseminated. Just a few years years later, I was again approached, this time by a Swiss firm dispensing various ferrite sheets for different types of aches and pains, with no hard evidence, merely testimonials by satisfied users. Similar to my first experience these people were also turned off by any thought of research.
However bad this history, things have improved recently. Some magnet companies have initiated intra- and extramural research projects, partly motivated by criticism of their clinical claims, but also because of competition among these firms. In addition, they probably realized that it is inevitable that the sales of permanent magnets for therapeutic purposes will eventually come under the eyes of the Food and Drug Administration and the Federal Trade Commission. Whatever the reason, research projects are now underway in a number of universities, hospitals, and other clinical settings that will hopefully follow prescribed protocols and lead to publications assessing the potential benefits.
Comparison to ELF Studies
One difference between ELF magnetic field claims and permanent magnet claims is that the public regards the former fields as bad for your health while imagining the latter fields as beneficial. Contrary to this media-driven view, many recognize that ELF magnetic fields have potentially important medical applications. For example, weak ELF fields are routinely involved in treating certain bone disorders under approved FDA protocols.
But there are key physical differences, as well. The one involves very weak intensities, the other is substantially greater. In the ELF case, one deals with time-varying fields, in the other, a magnetostatic field. And, usually the ELF applications do not involve the large gradients that are found in permanent magnets.
Is There a Credible Physical Interaction?
Despite these differences, there is one thing common to both cases, namely the need to establish physical credibilty. One has to separate out the likelihood of physical interaction for ELF effects from physiological interactions. Unlike the uncertainties connected to merely giving pills or practicing surgery, physics has a well-honed understanding of how Maxwell's Equations work, even in tissue. Robert Adair, Emeritus Professor at Yale has strenuously argued[4] that there cannot be any weak ELF biological effects whatsoever, hazardous or non-hazardous, if the applied magnetic signals are so small as to be lost in the thermal noise. A similar consideration must hold forth as a prerequisite for any putative therapeutic effect due to permanent magnets. We are therefore justified in asking, even before considering the possibility of a physiological effect, whether there is there any conceivable physical interaction that may underly the claims that are being made.
The physical interaction underlying most "successful" ELF experiments, (i.e., those not dealing with questions of hazard, but rather seeking any physiological change) mostly fall into two empirical frameworks. The first is similar to ion cyclotron resonance (ICR)[5], where one applies parallel sinusoidal and static fields with the frequency-to-intensity ratio adjusted to equal the charge-to-mass ratio of biological ions such as Ca2+, Mg2+, and K+. It seems very unlikely that such a mechanism could play a role in permanent magnet interactions.
Physiological changes due to ELF magnetic fields have also been observed that are connected to Faraday induction of weak currents. Faraday induction in the field of a permanent magnet requires motion of conductive tissue relative to the magnet. For a magnet placed directly on the skin, the most promising configuration occurs when tissue moves with velocity v in the direction of the gradient, such that dB/dt = v (dB/dz). Detailed calculation reveals that for red blood cells in motion, such induced currents can amount, at most, to merely a few electrons per second.
Unlikely as Faraday induction may be, there are magneto-mechanical forces that could play a role. Biological tissues are for the most part diamagnetic, and there are measurable forces on diamagnetic materials in large gradient fields. This force is proportional to the product B (dB/dz). Ueno [6] has demonstrated that water can be visibly parted (the "Moses effect") in superconducting field gradient products of ~400 T^2/m. For a typical high Hc-magnet the corresponding value for this product is one hundred times smaller. Calculation reveals that the force on a unit mass of tissue due to a high-Hc magnet is orders of magnitude smaller than that exerted on a single myosin muscle fiber (3 pN) resulting from the energy transformation of a single ATP molecule7.
Nonetheless there is a mechanism that could conceivably provide a measurable interactive basis between magnet and tissue. Many biomolecules exhibit diamagnetic properties that are tensorial, with the diamagnetic susceptibility in one direction very different from that in other directions. This diamagnetic anisotropy can result in a torque, the size of which varies not only with the field strength but also with the number of adjacent, aligned molecular repeats. For biopolymers this number can be as high as 108 ~10l0, the latter occuring, for example, in the retina[8]. For such arrays the orientational energy can be equal to or greater than kT in fields of 1-10 T. Further there are many reports9 indicating that biomolecular arrays such as collagen, lipids, and DNA undergo substantial orientation in fields only 10-100 times greater than that found within a few mm of a NdFeB magnet surface.
Diamagnetic Anisotropy and MRI Fields
It is reasonable to ask why no such effects have been reported for the hundreds of thousands of patients who are subjected each year to MRI examinations. Perhaps the MRI investigators [10] were only seeking hazardous consequences, and avoided more subtle effects not included among the stark toxicity requirements of the FDA. (Actually, there is one reliably documented high-field effect. As first reported a century ago by d'Arsonval, placing one's head into an intense field results in flashes of light (magnetophosphenes), presumably initiated directly in the retina.) In any event, despite the outlandish claims and hoopla attached to magnet therapy, there may indeed be reason to ask whether magnets can interact with tissue. Nevertheless, it is best to remember that the presence of an interactive mechanism does not, by itself, mean that there has to be a therapeutic outcome. It just makes the whole thing more reasonable.
1. C. K. Chou, "Electrochemical treatment of tumor". and following articles in
Bioelectromagnetics 18: 1 (1997)
2. A. R. Liboff and M. Chopp, "Should the premed requirements in physics
be changed?", Am. J. Phys. 47., 331-336 ((1979).
3. The Bakken Library and Museum in Minneapolis has a collection of
devices on display, as well as books and articles ,dealing with elect
romagnetics in medicine, both fraudulent and useful.
4. R. K. Adair, "Constraints on biological effects of weak ext remely-
lowfrequency electromagnetic fields". Phys. Rev. A 43: 1039-1048, (1991).
5. A. R. Liboff "Geomagnetic cyclotron resonance in living cells" J. Biol.
Physics 13: 99-102 (1985).
6. S Ueno and M. Iwasaka, "Properties of diamagnetic fluid in high
gradient magnetic fields." J. Applied Phys. 75. 7177-7179 (1994).
7. J. T. Finer, R. M. Simmons, and J. A. Spudich, "Single myosin molecule
mechanics: piconewton forces and nanometre steps." Nature 368: 113-119,
8. F. T. Hong, D. Mauzerall, and A. Mauro, "Magnetic anisotropy and the
orientation of retinal rods in a homogeneous magnetic field". Proc. Acad, Sci.
USA 68: 1283-1285 (1971).
9. J. Torbet, J-M. Freyssinet, and G. Hudry-Clergeon, "Oriented fibrin gels
formed by polymerization in strong magnetic fields". Nature 289: 91-93 (1981).
10. R. B. Frankel and R. P. Liburdy, Biological effects of static magnetic
fields, Chapter 3 in C. Polk and E. Postow (editors) Handbook of Biological
Effects of Electromagnetic Fields , 2cd edition, CRC Press, New York (1996).
A.R. Liboff
Department of Physics
Oakland University
Rochester, MI 48309
(248) 370-3412