- 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.
-
- References
-
- 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,
- (1994).
-
- 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
- Liboff@oakland.edu
- (248) 370-3412
|
