The ministry of AYUSH (Ayurveda, Yoga and Naturopathy, Unani, Siddha and Homeopathy), Govt. of India recently promoted Magnet therapy on their twitter handle ‘@moayush’ as part of the promotions of Naturopathy Day (Prakritik Chikitsa Divas) in India on November 18.
As per principles of Naturopathy, magnetic treatment is to be applied directly to the affected body parts by the therapeutic magnets, or as general treatment to the body. Specially designed magnetic belts are available for different parts of the body. pic.twitter.com/fli5oAjwGO
— Ministry of AYUSH (@moayush) November 14, 2018
Practised by naturopaths, magnet therapy is the use of magnets for disease treatment. The magnets are attached to the body with the help of adhesives or worn in the form of jewellery like bracelets or necklaces. Depending on prescription, the magnets can be worn for a varied length i.e. for a few minutes to days or even weeks depending upon the site of the application and the therapists’ prerogative.
On the website of AYUSH, it is stated that, “Magnet therapy is a clinical system in which human ailments are treated and cured through the application of magnets to the body of the patients.”
In this article, we will discuss:
- The three claims by which magnet therapy is known to work, and
- Large scale meta-analyses to evaluate the benefit of magnet therapy
How does it claim to work?
Those who practise magnet therapy argue that some tissues and cells emit electromagnetic impulses, and that illness and/or injury disrupt these electromagnetic impulses. It is claimed by proponents of magnet therapy that these disruptions can be restored by the use of magnets, thus treating the ailment. Magnet therapy is claimed to treat diseases such as headaches including migraines, arthritis, and stress-related pain can be relieved.
Claim 1: Magnet therapy increases blood flow to the affected areas to produce a positive effect
Iron is a major component of red blood cells (RBCs). Iron in these cells are contained in a metal-protein complex called haemoglobin, which temporarily bind with oxygen molecules in the lungs, circulate in the body, and ‘detach’ in the rest of the body sites such as muscles. The RBCs lacking oxygen then return to the lungs via the heart. These RBCs flow in the circulatory systems with veins and arteries, for blood lacking oxygen (de-oxygenated) and containing oxygen (oxygenated) respectively.
Since, iron is known to attract itself to magnets, it is hypothesised that iron in the blood will also act in a similar way. A study published in 1936 in the Proceedings from the National Academy of Sciences, on the magnetic properties of oxygenated and deoxygenated haemoglobin concluded that the iron in blood is not ferromagnetic.
Also, the study stated that while oxygenated blood and plasma are diamagnetic, and may actually slightly repel a magnet so there would be no physiological effect of an external magnet; non-oxygenated blood is weakly paramagnetic which attracts slightly to a magnet. However, blood flows in a high pressure and turbulence to have no effect of a permanent magnet on its flow. Hence, magnet therapy cannot have a measurable effect on blood flow.
A study by Mayrovitz and colleagues showed that there was no difference in blood flow on skin when compared in a group of healthy people in which magnet was placed in one hand and a sham (no magnet) was placed in another hand. The measurement of skin blood perfusion by a method called laser Doppler flowmetry and imaging showed no significant differences in the blood flow of either hands.
Hence, there is no evidence to support the claim of increased blood flow to the areas where permanent magnets are applied.
Claim 2: Increasing the magnetic field strength increases the penetration of the field into the skin and hence the overall effect on blood flow
The principle of oxygen loss and gain in the blood is used for magnetic resonance imaging (MRI) devices. MRI uses the blood oxygenated status to reveal detailed bodily structures, in particular the brain and the spinal cord. But an MRI machine does not produce a magnetic effect of repellence or attraction on human bodies, only to metal objects attached onto them.
Additionally, while the magnetic field produced in MRI machines is relatively high, permanent magnets used in magnet therapies are very weak to even penetrate the skin and influence the flow of blood. For example, a standard small sized magnet can be of 0.001 Tesla/ 10 Gauss (unit of measurement for magnetic field), while a standard MRI machine starts from 1.5 Tesla/ 15000 Gauss.
Stick C and his group studied the impact of strong magnetic fields emanating from Nuclear Magnetic Resonance (NMR) systems, used for medical imaging as well as to depict molecular structures of organic compounds. They used 0.4T to 1T (Tesla) to apply on a small area on the body and concluded that at such high strengths, no effect was found in the local blood flow to the thumb or forearm.
Another technique, called trans-cranial magnetic stimulation (TMS) also uses two magnetic coils to produce excitatory or inhibitory changes, specifically at a single point, in the neural tissue such as the brain. In this method, repeated bursts of high intensity magnetic stimulation are often delivered at the rate of 1 Hz (one burst per sec), to modulate a local region in the tissue. However, the intensity of TMS therapy is as high as 1.5T to 2T (similar to MRI machines) delivered repeatedly over a short period of time.
Hence, high dose magnetic strength is unable to influence blood flow or oxygen flow to tissues where it has been applied. Also, TMS is limited to stimulation of neural tissues or cells that are excitable.
Claim 3: Magnet therapy can provide pain relief.
This claim that magnet therapy for 45 mins can abolish pain perception emerged from a 1997 study, led by Vallbona and colleagues. The study showed beneficial effects in a small group of patients, however, the results remained controversial due to the use of a small subject number (n=50). The study was never replicated in a larger group and hence, the effect was proved scientifically unsubstantial.
In another study published by Brown and colleagues in 2002, it was concluded that chronic pelvic pain reduced after wearing active magnets for 4 weeks, however, due to the subjects’ awareness of the therapy, the lack of ‘blinding’ may have impacted on the change in pain perception.
The patients receiving active magnets were more likely to guess that they had received the active therapy instead of a sham magnet. This knowledge of therapy clearly creates a bias in the patients mind and contributes to a ‘placebo effect’.
Since pain perception is subjective and largely reliant on pain expectations, it can be easily manipulated by placebo treatments. Also, such methodologies where, subjects are not appropriately blinded for therapies, goes against the principles of scientific testing.
Large-scale meta-analysis research studies that show magnet therapy is ineffective
Meta-analyses are those in which a group of similar studies are taken together and the data is pooled to have a larger sample size to better evaluate the efficacy of a treatment.
1. A 2007 meta-analysis study by Pittler and colleagues, showed that magnets did not improve pain as compared to a placebo in patients of diabetic peripheral neuropathy, low-back pain, plantar heel pain and foot pain. In the osteoarthritis groups, the positive effects were visible, however, the evidence was not insufficient. This insufficient evidence related to magnetic therapy use in osteoarthritis was also shown in 2012 by Macfarlane in another systematic review.
2. Another study published in 2007 by Cepeda and colleagues showed that magnetic therapy lacked efficacy in decreasing pain or opioid requirements following surgery. A carpel tunnel syndrome pain study showed no benefits of magnet therapy. In this study, the researchers made sure the magnets and shams (fake magnets) were boxed separately to avoid compromising the study. Surprisingly, both magnet and the sham receiving group showed improvement but both had no statistical difference between them showing that psychological placebo effect plays a huge role in such treatments.
- The low field strength of permanent small magnets used in magnetic therapies and inability of blood to be ferromagnetic, small body magnets may not have any appreciable effect on blood flow.
- There is also no evidence of strong magnets like MRI, which easily penetrate the skin and enter deep lying organs, of producing any effect on blood flow.
- Pain relief studies conclude that such studies do not account for double blinding. Since pain is a highly subjective sensation, patient expectations, due to belief in a certain therapy, can hugely modulate pain perception.
- Lastly, large meta-analysis and studies conducted with patient blinding, concluded that magnet therapy was ineffective in various pain conditions.
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