Wednesday, February 13, 2008

Magnetic therapy update (static)

in people and animals: still a bust

A recent 2008 article in Livescience discusses the apparently promising outcome of a new study on static magnetic therapy in rats. The author notes that “Thomas Skalak of the University of Virginia found that static magnets reduced swelling by up to 50 percent in the tiny hind paws of rats. Skalak published his results in the November issue of the American Journal of Physiology.”

The actual study “Chronic static magnetic field exposure alters microvessel enlargement resulting from surgical intervention” used neodymium static magnetic field (SMF) magnets or weight-matched shams that were affixed to murine skin fold chambers on rats and observed the adaptive microvascular response over seven days. Neodymium (NeFeB) rare earth magnets are the strongest static magnets available and seem to be the favored magnet type in much of the research.

According to Skalak using static magnets (these had a strength of 700 gauss -“10 times stronger than a refrigerator magnet”) he was able to observe a significant reduction in “bee sting or sprain level” swellings. The impact was strongest when the magnets were applied immediately to the affected area.

Among the possible mechanisms for the observed results, Skalak mentions was the possibility that these magnets may alter calcium channels in muscle cells thereby modulating arterial dilation; an in vogue theory in magnetic theory circles. The study states that “These results suggest that chronic SMF exposure can alter the adaptive microvascular remodeling response to mechanical injury, thus supporting the further study of chronic application of SMFs for the treatment of vascular pathologies involving the dysregulation of microvascular structure.”

This study may or may not yield interesting information as it is analiyzed in more detail, but even added to the paucity of positive studies that have evaluated magnetic therapies (including static as well as other magnetic configurations and field strengths) it still leaves room for serious doubt on whether magnets in general really work for these applications.

To his credit, Skalak notes that this study only looked at one specific field strength for a specific swelling at a specific distance below the skin therefore any implications for the efficacy of the plethora of magnetic products on the market should be discouraged.

Other studies seem add to the confusion. For example, a 2006 study looked at the effect of SMF magnets on healing rat colons. These magnets were made of NeFeB and with between 390-420 gauss in strength and the shams were non-magnetized NeFeB bars similar in weight and size. The authors found no difference in effect and that “The study results suggest that static EMF has no effect on experimental colonic wound healing in the rat.”

Interestingly, a critical review was published a little before Skalaks' study in the Evidence-based Complementary and Alternative Medicine Journal. It found that the existing studies on SMF could not be reasonably tied together due to a number of confounding variables including differing magnetic field strengths, magnet dimensions, durations of application, and distances from target tissue. They conclude “Our findings highlight the need to optimize SMF dosing parameters for individual clinical conditions before proceeding to a full-scale clinical trial.” In essence, there is too much fog in the research; it is not clear exactly what is being done to what tissue and with what magnets to even establish whether these things even work on humans- and this from a CAM journal no less (however nice the title sounds).

This is consistent with the NCCAM “Research Report” that states "Scientific research so far does not firmly support a conclusion that magnets of any type can relieve pain. However, some people do experience some relief. Various theories have been proposed as to why, but none has been scientifically provem." Though this equivocation is typical for NCCAM ( a never admit defeat line) they finally acknowledge that the "results of many trials may not be truly meaningful. Most reviews stated that more and better quality research is needed before magnets' effectiveness can be adequately judged." And even add that "The U.S. Food and Drug Administration (FDA) has not approved the marketing of magnets with claims of benefits to health (such as "releives arthritis pain"). The FDA and the Federal trade Commission (FTC) have taken action against many manufacturers, distributors, and web sites that make claims not supported scientifically about the health benefits of magnets."

So what are we to make of all the activity and discussion over static magnetic field magnets? For now, nothing at all- there is no compelling evidence that SMF magnetic therapies work in the clinical setting. Even the supposedly intriguing microvascular rat studies are too far removed and too specific to give any support to current SMF magnet therapies or justify the billion dollars spent worldwide by the public on magnets that don’t help heal anything.

On plausibility

In spite of some vaguely promising results in some studies using certain magnets, just how plausible is this whole magnet idea?

In a January, 2006 editorial comment in the BMJ professor of physics Leonard Finegold sums up things pretty well stating that “Extraordinary claims demand extraordinary evidence. If there is any healing effect of magnets, it is apparently small since published research, both theoretical and experimental, is weighted heavily against any therapeutic benefit. Patients should be advised that magnet therapy has no proved benefits. If they insist on using a magnetic device they could be advised to buy the cheapest—this will at least alleviate the pain in their wallet.”(1)

On that note, it behooves us to briefly look into some of the physics involved with magnets. Living bodies are basically made up of inert materials and are described as diamagnetic meaning they are not only un-attracted to magnetic fields, they are actually weakly repelled by them. This physical phenomenon does not seem have any obvious tissue effects with respect to the supposed clinical effects of SMF magnets in spite of the number of theories that claim they do.

The earths' magnetic field is at the strength of just less than half a gauss whereas most magnetic therapy magnets usually have a field strength of several hundred gauss. The magnetic filed strength of a standard MRI of around 10,000 gauss (one tesla) causes no obvious changes to people or animals- nobody explodes or is shot through the air as you might expect if that were so.

By the way, it takes powerful electromagnets of around 160,000 gauss (16 telsa) to see magnetic effects begin to counter balance some modest gravitational forces2. At this level, if you put small objects such as water droplets, flowers, and little frogs within this type of magnetic coil you can actually “levitate” them (you need a lot more power than 16 telsa to make a human float)! This interesting information shows how small the effect therapeutic magnets are compared to other devices (some used routinely) where one would expect to observe the same or related effects as those claimed to occur with SMF magnets.

It seems the researchers hopes are pinned on some as yet undiscovered effect for example such as those mentioned to purportedly effect ions or channels that may influence such larger events as inflammation or vascular function. The problem though is no real and repeatable clinical effect has been either demonstrated or established!

More problems for magnets

Medical researcher Bruce Flamm comments on he and professor Finegolds 2006 BMJ review of magnetic literature which found little supporting evidence for magnetic efficacy. He notes that though the human body might be affected by electromagnetic fields of electromagnets (due to the generated electricity- known to affect tissue) it does not seem to be affected by magnetic fields per se. For example, the iron in blood is not composed of ferromagnetic iron and is not affected by a magnet. In addition, in spite of the above mentioned rat study and calcium channels; several other studies show no effects on blood flow from static magnetic fields.

Flamm notes the bottom line is that even if “for the sake of argument, what if some effect of magnets on human tissue could be demonstrated? What is the likelihood that it would be a therapeutic or healing effect? Probably slim to nil. By analogy, consider chemical compounds. The number of known chemical compounds is on the order of ten million. However, only a handful have ever been shown to have any therapeutic effects. Yet millions are toxic. It would be most unwise to eat or drink anything found on the shelves of a typical chemistry lab. If a magnet had an effect on human tissue, there is no reason to believe that it would necessarily be a healing effect.”

Veterinary medicine is replete with its own assortment of mostly SMF magnetic paraphernalia. They come in a variety of forms such as blankets, pads, bandages, and bedding to fit and “treat” all animals large and small. Depending on the company, these magnets are constructed to have alternating numbers of poles (Some claim the more alternating north and south poles the stronger the effect. In reality though this magnifies a magnets stick power it shortens an already short range).

Some alternative medicine (CAVM) veterinarians extol the possible benefits of magnetic therapy either by itself or as an “integrated” modality with other medicine even if they are not sure how they work.Others seem to support their use while attempting to distinguish between "good and bad" magnets and discuss differences in static versus pulsed electromagnetic field therapies (PEMF- breifly touched on in the footnote below) .

The problem is static magnetic therapy is an implausible modality and as far as we know doesn't work. Researchers are not even sure they can find a way to make it work! This is another CAM modality where the claims and beliefs in “healing” powers have far outstripped any of the evidence that it actually does anything but make people poorer.

This wise old piece of advice goes a long way: Its a good thing to keep an open mind…but not so open that your brains fall out.


(1) On the other hand, that same month a research fellow named James Teo noted "Not all magnetic devices are equally non-efficacious. Magnetic fields from bracelets and such may have little effect on human tissue, but it would be wrong to discount all effect on human tissue...There is a strong research literature using transcranial magnetic stimulation (TMS) to induce neuronal firing in the brain and spinal cord.. while no large clinical trials have been done yet, it is crucial that not all magnetic therapy should be discounted."

This comment alludes to another form of magnetic devices used described as pulsed electromagnetic field (PEMF) therapy (worth a future post). Though still questionable, these magnetic devices use electromagnetic pulses of varying telsa strengths to generate electrical fields. The effect, if any, probably has to do with the electrical feilds and not magnetism. Some people use pulsing electromagnetic fields in people, horses, and other animals applying varying frequencies and pulses- the exact intensities of which are determined by blind intuition rather than hard facts.

Though there may be some merit to this unproven theory, it is important to remember that cells and tissues seem to respond to a variety of different electrical stimuli implying that specific impulses, sequence, and cell types might play into any real response and what might work one place won’t somewhere else. Many proponents of PEMF consider it a promising future modality- time will tell.


Other Ref:

Ramey D, Rollin, B. Complementary and alternative veterinary medicine considered.Iowa State Press.Ames, Iowa. 2004


Magnetic therapy in vet practice


HansMassage said...

My search for an explanation to the observed effects of magnets in my therapeutic work has led to the effect noted in non medical science. Magnets affect electrons. Altered electron speed alters the bonding of water molecules which bond in various configurations when they change from water vapor to liquid water.
The only consistent effect I have observed in using magnets therapeutically is the change in movement of fluids between the cells. Fluids move more easily out of swollen areas and more easley ind dehydrated ones.
From my perspective pain is a report of impaired function. Reduction of pain is a report of improved function. Therefore if magnets as a tool help me improve function I use them. My goal is to set up a study to demonstrate that therapy done with a magnet compared to a sham takes less time and produces less subjective pain.
Hans Albert Quistorff, LMP
Antalgic Posture Pain Specialist

wandering primate said...

Problem is there are no real confirmed effects...most of what is observed is likely placebo. There has been a lot of discussion on the palcebo effect here and on other blogs.
Body fluids like blood and water are weakly diamagnetic (repelled by magnets)but it doesn't seem to affect molecular structure beyond that. Static Magnets used in therapy produce diamagnetic forces thousands of times smaller than gravity. They are also one dimensional whereas tissue activity is three dim. It's hard to see how they could effect inflammatory physiology (very complex)i.e.; tumefaction, edema, cellular mediators...etc. to a level that would be clinical.
Subjective (human) pain is a whole different thing...