Equine magnetic therapy: the positives and negatives

You want to believe. You really do. And there are many well-known horsemen, doctors, physicists and PhD's telling you that you should.

Dr. Robert Holcomb MD, PhD, at the Vanderbilt University Medical Center, writes, "Magnetic fields produce the following results when in direct contact with the body: increased circulation; vasodilatation; muscle relaxation; reduction of edema; reduction of nerve-cell firing (which reduces pain); and reduction of free radicals (which improves the body's ability to fight inflammation and improves the immune system).

Magnetic-therapy proponents rely on physics to validate their belief in the healing action of magnets and will take you through a discussion of Faraday's Law and the Hall effect. "The combination of the electromotive force, altered ionic pattern and the currents (caused by physical effects based on physics principles) causes blood-vessel dilation with a corresponding increase in blood flow," states Dr. M. Porter in a 1997 article in Equine Vet Data.

Your clients see advertisements for magnetic-therapy devices in all the popular equine magazines, and owners and trainers routinely give testimonials as to the varied beneficial effects that these units produce.

What could be better than to apply a magnetic joint wrap, footpad or body blanket and improve circulation, reduce inflammation and help your horse heal?

You'd really, really like to believe, but ...

Arguments pro and con

The problem is that there are equally many well-known scientists, clinicians and researchers on the other side of this issue.

David Ramey DVM, a California practitioner fast becoming the "Ralph Nader" of the profession, concludes, "There appear to be no published scientific studies available that demonstrate that any form of magnetic therapy is valuable in the treatment of disease conditions in the horse."

Dr. Phillip Steyn and a group of researchers in the Department of Radiological Health Services at the College of Veterinary Medicine at Colorado State University looked at the effects of static magnets on blood flow in the metacarpas of the horse and concluded, "static magnetic fields associated with the application of commercially available magnetic wraps for 48 hours did not increase the blood flow pattern of the metacarpas under the wrap."

Even though electromagnetic field therapy used for treatment of delayed and non-union fractures in humans is FDA-approved and supported by numerous studies, work by Dr. Bramlage, Dr. Collier and others failed to show similar usefulness in the horse. Other studies done in horses call the claims of "increased blood flow" and "pain reduction" following magnetic therapy into question.

But no sooner than you decide to discount this modality, a new study is published that makes you rethink your position — again.

Dr. Carlos Vallbona investigated the pain response in post-polio patients at the Baylor College of Medicine's Institute for Rehabilitative Research in Houston, Texas. In a double-blind study of 50 patients using magnets, a significant reduction in pain was reported by those patients using active magnets as opposed to patients using "sham" magnets. Twenty-nine of the patients with active magnets reported that, on average, they felt a reduction in pain from 9.6 to 4.4 (0 to 10 scale) while the 21 other patients using the sham magnets reported a reduction in pain of 9.5 to 8.4. This significant difference lends some "science" to the magnetic-therapy discussion.

Dr. William Jarvis, president of the National Counsel Against Health Fraud, previously was a detractor of magnetic therapy, calling it "essentially quackery." But after Dr. Vallbona"s findings were published, Dr. Jarvis tentatively admits that it (magnetic therapy) may have value.

Dr. Michael Weintraub and the magnetic-research group from the Department of Neurology at New York Medical College reported a randomized, double blind, placebo-controlled study looking at the reduction in diabetic-associated peripheral neuropathy achieved by wearing static magnetic shoe insoles.

These investigators concluded, "Although many questions remain about a precise mechanism of action, the present study provides convincing data confirming that the constant wearing of static, permanent, magnetic insoles produces statistically significant reduction of neuropathic pain." This study and others have led some veterinarians and owners to try magnetic footpads or magnetic bell boots as treatment for hoof-related pain.

Study results questioned

Some scientists, however, question whether the Baylor study and Dr. Weintraub's investigation were truly "blinded," reasoning subjects could determine which group they were in. If your treatment device sticks to the refrigerator or nails stick to your shoe, then you have real magnets; if not, then you are in the "sham" group.

Some doubting researchers also point out that many of the investigators engaged in magnetic-therapy research are associated with companies that produce magnetic products or groups dedicated to promoting the benefits of magnets. This, they claim, may be enough to invalidate their work.

These "pro-magnet" researchers lament that the more mainstream medical community has been extremely slow to try to further research and investigate. This has forced individual veterinarians, doctors and other scientists who are passionate about magnetic therapy (hence their involvement in companies or such which produce magnets) to become researchers themselves.

Another problem for anyone trying to make sense of all the information available is that there is no agreement on factors such as magnet strength, magnet configuration or the mechanisms of magnetic action on tissue.

Though the precise nature of cellular electromagnetic response is not known, it has been theorized that cellular proteins may be involved in a signaling mechanism at the level of the cell membrane that could lead to information transfer.

The magnetic-to-electrical-to-cellular response links have not been worked out to date, and Dr. Ramey fairly summarizes, "The hypothesis that electrical signals may be responsible for information transfer in or to cells has neither been proved nor disproved."

James D. Livingston, a physicist in the Department of Materials Science and Engineering at the Massachusetts Institute of Technology, cautions, however, that "the efficacy of magnetic therapy (or of any other medical treatment, mainstream or alternative) does not depend on our understanding the biological mechanism."

Still, a crucial piece for the scientific community in the process of accepting "why it works" will be at least the beginning of an understanding into "how it works."

A scientific criticism of much of the magnetic-therapy research is that the magnet strength used in many of these studies is very weak.

Magnet-field strength is recorded as 1 Tesla = 10-4 Gauss. California Institute of Technology testing recorded the field strength of a popular brand of equine magnetic wraps as 270 Gauss at the level of the pad and 1 Gauss at a distance of 1 cm from the pad.

According to Dr. Ramey's research, 1 Gauss is approximately the magnetic-field strength of the Earth and not likely to have any biological effect on equine tissue.

Magnetic design varies greatly between companies, but there is no clear scientific data that either supports or discredits any particular configuration.

Some users favor unipolar magnets, while others favor bipolar designs. Alternating poles make the gradient greater but reduce the functional size and strength of the magnetic field. Some companies argue that a concentric-ring pattern to their magnets will produce a greater field and effect while other companies use a triangle pattern to attempt to accomplish the same goal.

At this time there does not appear to be any sound evidence to suggest that a particular field strength or magnet configuration offers any particular advantage over any other.

More research needed

For every testimonial and study on one side of the argument there appears to be a counter on the other. Clearly the use of magnetic therapy in the horse is a controversial issue that demands more research and investigation in order to let the scientific community come to a unified consensus.

Dr. Ramey concludes by stating, "Explanations that magnetic fields increase circulation, reduce inflammation or speed recovery from injuries are simplistic and not supported by the weight of experimental evidence."

"More studies will be needed before magnetic therapy will be accepted by a majority of the medical community," says Dr. Livingston, "and some studies are already under way."

Dr. Ann Gill Taylor has received a $1 million grant from the NIH Office of Alternative Medicine to study the use of magnets to relieve pain. The Center for the Study of Complementary and Alternative Therapy in the School of Nursing at the University of Virginia will use this grant to investigate the effects of pulsed and static magnetic fields on neuronal processes and on microvascular capillary blood flow.

The mere fact that the NIH has committed so much funding to magnetic-therapy research points out how interested the medical community is in resolving this debate and the hopefulness that many have in this field.

For an idea that has been around since the 1500s, there are still many unanswered questions about magnets and their use in medical treatment.

Magnetic therapy has fallen into and out of favor over the years. Perhaps current research will yield the elusive scientific proof that has been missing for so long and will finally make it possible for us to really believe.

Marcella is an equine practitioner in Canton, Ga.