Magnet therapy, or magnetic therapy, is a pseudoscientific form of alternative medicine based on the concept that certain medical disorders can be effectively treated by exposure to magnetic fields. Some believe that magnetic fields emanating from permanent magnets placed close to the body can cause bones to heal faster, relieve pain, and perform other forms of healing to the body. It is most commonly recommended by practitioners as a cure for joint disorders and back problems. Critics charge that no verifiable evidence has been put forth that magnet therapy has any real benefits, and thus relegate it to the realm of pseudo-science. It may act as a placebo in some people.
Proponents of magnet therapy claim that subjecting certain parts of the body to doses of magnetic "energy" (or fields) has a beneficial effect. This belief has led to the popularization of an industry involving the sale of magnetic-based products for "healing" purposes: magnetic bracelets and jewelry; magnetic straps for wrists, ankles, and the back; shoe insoles, mattresses, and magnetic blankets (blankets with magnets woven into the material); and even magnetic water (water that has been "magnetized"). Criticism of these products focuses on various scientific facts about magnets, including the claim that the typical magnet used in a bracelet purchased over-the-counter is not powerful enough to penetrate human skin, let alone strong enough to have a lasting effect on muscle tissue, bones, blood vessels, or organs. Notably, some people working in physics research work for hours per day with their whole body immersed in magnetic fields far stronger than those from the bracelets, and (if they observe precautions regarding pacemakers) are no more or less healthy than their peers. There are handheld neodymium magnets that produce a field of over one tesla and are often used in various hobbies. Household devices such as a garbage disposal, or an electric razor, also produce significant magnetic fields when in use.
Few magnet healing product manufacturers have demonstrated scientifically that they actually achieve what they claim, and most cannot even agree on what exactly the magnetic fields do. Some claim that the magnets help to circulate the blood by some interaction with the iron in hemoglobin, a major component of red blood cells. However, in its ionised form, iron is not ferromagnetic. If it were, use of magnetic resonance imaging would instantaneously kill patients. Still others claim that the magnets can restore the body's electromagnetic energy balance. There are also claims that the south pole of a magnet acts different on the body than the north pole. The list of ways that manufacturers purport that magnetic fields affect the body is almost endless.
The vast majority of information sources and Web sites promoting magnetic therapy belong to people and understandably biased companies that sell magnetic products.
Mesmer and Magnet Therapy
In 1766 Dr. Franz Mesmer introduced a technique which he called "animal magnetism," in his doctoral thesis, De planetarum Influxu, which was in turn heavily influenced by the works of Richard Mead. He theorized initially that the influence of the planets was somehow related to magnetism, and that these influences could be reproduced and cures effected by stroking diseased bodies with magnets. In 1773 Mesmer successfully defended a legal claim by the Jesuit priest, Maximilian Hell that Mesmer had stolen his ideas about the use of magnetism. When Mesmer became familiar with the work of the celebrated Swiss exorcist, Johann Joseph Gassner he abandoned the use of magnets, preferring the hypothesis that there existed a naturally occurring force in the living body, i.e. animal magnetism. With this the term "magnetism" became ambiguous, and the path that led to magnet therapy became known as ferro-magnetism. In 1784 the French government established a commission, chaired by Benjamin Franklin to investigate the medicinal value of animal magnetism; within the narrow terms of reference of that commission animal magnetism was found to have no curative value.
Animal magnetism was a forerunner of what would later became better known as hypnosis (hence "to mesmerise"). The term "animal magnetism" is used today as a popular reference to the supposed ability of some people to attract or be attracted to each other.
Repetitive Transcranial Magnetic Stimulation
Repetitive Transcranial magnetic stimulation (rTMS) is currently under study as a possible treatment for depression, auditory hallucinations, and possibly to temporarily induce savant-like abilities. Initially designed as a tool for physiological studies of the brain, this technique shows promise as a means of alleviating depression. In this therapy, a powerful magnetic field is used to stimulate the left prefrontal cortex, an area of the brain which typically shows abnormal activity in depressed individuals. Studies currently show an efficacy similar to that of electroconvulsive therapy (ECT), but with fewer side effects. No sedation is required, and the only reported side effects are a slight headache in some patients, and facial muscle contraction during treatment. A study by the World Parkinson Disease Association (a non-profit organization) gave inconclusive results:
"In this Japanese multi-center, double-blind study, rTMS was compared with sham stimulation in two groups of PD patients. Some efficacy was observed in rTMS treated subjects, but the degree of the effect was not significantly different from that of the control patients. The existing reports have been conflicting regarding the efficacy of the r TMS in PD, on the base of the differences of the stimulation parameters and the relevance of the placebo effect of the procedure. The results of this study do not prove the efficacy of rTMS, but they do not rule out definitely possible positive effects." -- Sunday, November 23, 2003
This form of treatment, however, involves extremely powerful focused electromagnets to produce a magnetic flux density of several teslas over a small region of the brain to produce eddy and induction currents. The flux density of even huge horseshoe magnets is five orders of magnitude weaker, and that produced by flat permanent magnets is far weaker still. Thus, rTMS is a very different type of therapy than what is promoted as "magnet therapy" in advertisements and on websites.
See also: Clinical depression
Evidence of Effectiveness
- Belci M, Catley M, Husain M. Magnetic brain stimulation can improve clinical outcome in incomplete spinal cord injured patients. Spinal Cord. 2004 Apr 27 [Epub ahead of print] PMID 15111994
Last updated: 05-13-2005 07:56:04