Magnet therapy

From Wikipedia, the free encyclopedia
Jump to: navigation, search
This article is about static magnetic fields in alternative medicine. For medical uses of electromagnetism, see Electromagnetic therapy (disambiguation).
Energy medicine - edit
NCCAM classifications
  1. Alternative Medical Systems
  2. Mind-Body Intervention
  3. Biologically Based Therapy
  4. Manipulative Methods
  5. Energy Therapy
See also

Magnet therapy, magnetic therapy, or magnotherapy is a pseudoscientific alternative medicine practice involving the use of static magnetic fields. Practitioners claim that subjecting certain parts of the body to magnetostatic fields produced by permanent magnets has beneficial health effects. These physical and biological claims are unproven and no effects on health or healing have been established.[1][2][3] Although hemoglobin, the blood protein that carries oxygen, is weakly diamagnetic (when oxygenated) or paramagnetic (when deoxygenated) the magnets used in magnetic therapy are many orders of magnitude too weak to have any measurable effect on blood flow.[4]

Methods of application[edit]

A smooth circular band of magnetite on a finger
Magnetite ring

Magnet therapy is the application of the magnetic field of electromagnetic devices or permanent static magnets to the body for purported health benefits. Some believers assign different effects based on the orientation of the magnet; under the laws of physics, magnetic poles are symmetric.[5]

Products include magnetic bracelets and jewelry; magnetic straps for wrists, ankles, knees, and the back; shoe insoles; mattresses; magnetic blankets (blankets with magnets woven into the material); magnetic creams; magnetic supplements; plasters/patches and water that has been "magnetized". Application is usually performed by the patient.[6]

Purported mechanisms of action[edit]

Perhaps the most common suggested mechanism is that magnets might improve blood flow in underlying tissues. The field surrounding magnet therapy devices is far too weak and falls off with distance far too quickly to appreciably affect hemoglobin, other blood components, muscle tissue, bones, blood vessels, or organs.[1][7] A 1991 study on humans of static field strengths up to 1 T found no effect on local blood flow.[4][8] Tissue oxygenation is similarly unaffected.[7] Some practitioners claim that the magnets can restore the body's hypothetical "electromagnetic energy balance", but no such balance is medically recognized. Even in the magnetic fields used in magnetic resonance imaging, which are many times stronger, none of the claimed effects are observed. If the body were meaningfully affected by the weak magnets used in magnet therapy, MRI would be impractical.[9][10][11]

Efficacy[edit]

Several studies have been conducted in recent years to investigate what role, if any, static magnetic fields may play in health and healing. Unbiased studies of magnetic therapy are problematic, since magnetisation can be easily detected, for instance, by the attraction forces on ferrous (iron-containing) objects; because of this, effective blinding of studies (where neither patients nor assessors know who is receiving treatment versus placebo) is difficult.[12] Incomplete or insufficient blinding tends to exaggerate treatment effects, particularly where any such effects are small.[13] Health claims regarding longevity and cancer treatment are implausible and unsupported by any research.[7][14] More mundane health claims, most commonly about anecdotal pain relief, also lack any credible proposed mechanism and clinical research is not promising.[6][15][16]

Magnet therapy has been promoted as a treatment for cancer and other diseases; the American Cancer Society state, "available scientific evidence does not support these claims".[17]

Pain[edit]

Effects of magnet therapy on pain relief beyond non-specific placebo response have not been adequately demonstrated. A 2008 systematic review of magnet therapy for all indications found no evidence of an effect for pain relief.[15] It reported that small sample sizes, inadequate randomization, and difficulty with allocation concealment all tend to bias studies positively and limit the strength of any conclusions. In 2009 the results of a randomized double-blind placebo-controlled crossover trial on the use of magnetic wrist straps (a leather strap with a magnetic insert) for osteoarthritis were published, addressing a gap in the earlier systematic review. This trial showed that magnetic wrist straps are ineffective in the management of pain, stiffness and physical function in osteoarthritis. The authors concluded that "[r]eported benefits are most likely attributable to non-specific placebo effects".[18][19]

Safety[edit]

These devices are generally considered safe in themselves, though there can be significant financial and opportunity costs to magnet therapy, especially when treatment or diagnosis are avoided or delayed.[6][14][15]

Reception[edit]

The worldwide magnet therapy industry totals sales of over a billion dollars per year,[7][14] including $300 million per year in the United States alone.[12]

A 2002 U.S. National Science Foundation report on public attitudes and understanding of science noted that magnet therapy is "not at all scientific."[20] A number of vendors make unsupported claims about magnet therapy by using pseudoscientific and new-age language. Such claims are unsupported by the results of scientific and clinical studies.[16]

Legal regulations[edit]

Marketing of any therapy as effective treatment for any condition is heavily restricted by law in many jurisdictions unless all such claims are scientifically validated. In the United States, for example, U.S. Food and Drug Administration regulations prohibit marketing any magnet therapy product using medical claims, as such claims are unfounded.[21]

See also[edit]

References[edit]

  1. ^ a b Park, Robert L. (2000). Voodoo Science: The Road from Foolishness to Fraud. New York, New York: Oxford University Press. pp. 58–63. ISBN 0-19-513515-6. "Not only are magnetic fields of no value in healing, you might characterize these as "homeopathic" magnetic fields." 
  2. ^ Wanjek, Christopher (2003). Bad Medicine: misconceptions and misuses revealed from distance healing to vitamin O. Hoboken, New Jersey: John Wiley & Sons. pp. 1–253. ISBN 0-471-43499-X. 
  3. ^ National Science Foundation, Division of Resources Statistics (February 2006). Science and Engineering Indicators, 2006. Arlington, VA. Chapter 7. 
  4. ^ a b Stick C; Hinkelmann K, Eggert P, Wendhausen H (1991). "Do strong static magnetic fields in NMR tomography modify tissue perfusion?". Nuklearmedizin 154: 326. 
  5. ^ Rawls, Walter C.; Davis, Albert Belisle (1996). Magnetism and Its Effects on the Living System. Acres U.S.A. ISBN 0-911311-14-9. 
  6. ^ a b c Singh, Simon; Edzard Ernst (2008-04-08). "Are we being hoodwinked by alternative medicine? Two leading scientists examine the evidence". Daily Mail. Retrieved 2009-08-18. 
  7. ^ a b c d Flamm, Bruce L. (July 2006). "Magnet Therapy: a billion-dollar boondoggle". Skeptical Inquirer (Committee for Skeptical Inquiry). Retrieved 2009-08-18. 
  8. ^ Polk, Charles; Elliot Postow (1996). Handbook of Biological Effects of Electromagnetic Fields. CRC Press. p. 161. ISBN 0-8493-0641-8. 
  9. ^ "Safety in Medical Imaging Procedures". 
  10. ^ "Is Blood Magnetic". The Naked Scientist. Retrieved 13 December 2012. 
  11. ^ "Does MRI attract the iron in your blood?". Revising MRI. Retrieved 13 December 2012. 
  12. ^ a b Finegold L, Flamm BL (January 2006). "Magnet therapy". BMJ 332 (7532): 4. doi:10.1136/bmj.332.7532.4. PMC 1325112. PMID 16399710. 
  13. ^ Altman, DG; KF Schulz, D Moher, M Egger, F Davidoff, D Elbourne, PC Gøtzsche, T Lang, Consort Group (Consolidated Standards of Reporting Trials) (2001-04-17). "The revised CONSORT statement for reporting randomized trials: explanation and elaboration". Annals of Internal Medicine 134 (8): 663–694. doi:10.7326/0003-4819-134-8-200104170-00012. PMID 11304107. 
  14. ^ a b c "Magnet therapies 'have no effect'". BBC. 2006-01-06. Retrieved 2009-08-18. 
  15. ^ a b c Pittler, Max H. (March 2008). "Static magnets for reducing pain". Focus on Alternative and Complementary Therapies 13 (1): 5. doi:10.1211/fact.13.1.0003. Retrieved 2009-08-18. 
  16. ^ a b James D. Livingston. "Magnetic Therapy: Plausible Attraction?". Skeptical Inquirer. 
  17. ^ "Magnetic Therapy". American Cancer Society. December 2012. Retrieved September 2013. 
  18. ^ Richmond, S. J.; Brown, S. R.; Campion, P. D.; Porter, A. J. L.; Moffett, J. A. K.; Jackson, D. A.; Featherstone, V. A.; Taylor, A. J. (2009). "Therapeutic effects of magnetic and copper bracelets in osteoarthritis: A randomised placebo-controlled crossover trial☆☆". Complementary Therapies in Medicine 17 (5–6): 249–256. doi:10.1016/j.ctim.2009.07.002. PMID 19942103.  edit
  19. ^ "Copper bracelets and arthritis". NHS Choices. 2009-10-19. Retrieved 2009-11-03. 
  20. ^ National Science Board (2002). Science and Engineering Indicators – 2002. Arlington, Virginia: National Science Foundation. pp. ch. 7. ISBN 978-0-16-066579-0.  "Among all who had heard of [magnet therapy], 14 percent said it was very scientific and another 54 percent said it was sort of scientific. Only 25 percent of those surveyed answered correctly, that is, that it is not at all scientific."
  21. ^ "Magnets". CDRH Consumer Information. Food and Drug Administration. 2000-03-01. Archived from the original on 2008-04-24. Retrieved 2008-05-02. 

External links[edit]