I recently had the opportunity to attend The Amaz!ng Adventure 5. While at Grand Turks, our final port, I was wandering through the duty-free shop looking for deals on liquor (Jack Daniel’s Single Barrel for $39!) when I happened upon a tableful of woo. Seeing as I was a medical student on a skeptical cruise, I had to stop and have my wife help make this video.
In my off-the-cuff video, I didn’t have the opportunity to mention the lack of scientific evidence for their claims. Even if the magnetic field did penetrate the skin, it still would not stimulate blood flow because the amount of iron in blood is far too small. If blood did have a strong magnetic attraction, your body would explode in an MRI (which would be cool, I admit).
I also didn’t have time to discuss the clinical trials that have been performed to evaluate efficacy. As usual with CAM research, earlier poor quality studies were weakly positive (1,2), while more recent high quality studies and meta-analyses are definitively negative (3,4,5).
I also forgot to mention the numerous court rulings in the late ‘90s and early ‘00s against companies making false claims about these products. This issue is discussed extensively on Quackwatch for those interested (6). In a nutshell, companies that fraudulently claimed to treat specific illnesses (arthritis, diabetic neuropathy, migraines, etc.) were sued. Now, they use nebulous phrases such as “support the healing process” or “restore natural energy.” You know, phrases that have not been evaluated by the Federal Drug Administration and are not designed to diagnose, treat or blah blah blah.
In short, magnet therapy is a great case study of CAM. The lack of scientific plausibility, the progression of the medical literature, and the FDA Miranda Rights statement are all characteristic of CAM. And if a lowly medical student can debunk it is less than a minute, how good can it really be?
1. Harlow T, Greaves C, White A, et al. Randomised controlled trial of magnetic bracelets for relieving pain in osteoarthritis of the hip and knee. BMJ 2004; 329:1450-1454
2. Vallbona C, Hazelwood CF, Jurida G. Response of pain to static magnetic fields in postpolio patients: A double-blind pilot study. Archives of Physical and Rehabilitative Medicine 1997; 78:1200-1203.
3. Winemiller MH and others. Effect of magnetic vs sham-magnetic insoles on plantar heel pain: a randomized controlled trial. JAMA2003; 290:1474-1478.
4. Pittler MH. Static magnets for reducing pain: systematic review and meta-analysis of randomized trials. CMAJ 2007; 177(7): 736-42.
5. Cepeda MS, Carr DB, Sarquis T, et al. Static magnetic therapy does not decrease pain or opioid requirements: a randomized double blind trial. Anesth Analg 2007; 104. 290-294.
Iron in the blood written by Sc00ter,
March 17, 2010
"it still would not stimulate blood flow because the amount of iron in blood is far too small."
Correct me if I'm wrong but I don't think the amount makes any difference. Iron in the blood is non-ferrous.
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Not only that... written by Griz,
March 17, 2010
...the magnet either attracts or repulses. Either way, in the vicinity of the magnet's field blood would be accelerated in one direction but impeded in the other. I don't see how that could "stimulate" blood flow.
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QFT written by JWideman,
March 17, 2010
Griz: "...the magnet either attracts or repulses. Either way, in the vicinity of the magnet's field blood would be accelerated in one direction but impeded in the other. I don't see how that could "stimulate" blood flow."
I suppose for broad enough definitions of "stimulate" or "flow". Like, ones that include "decrease" or "clot", respectively.
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... written by cleetus8,
March 17, 2010
ScOOter - depending on the definition...any iron can be ferrous. In chemistry ferrous is a +2 oxidation (ferric is +3). Generally, though, in common usage any metal with iron in it is "ferrous."
The iron in blood (and blood itself) is slightly magnetic, but 1) the magnets used in the bands (as demonstrated) are too thin to penetrate the skin and 2) even more so, not powerful enough to effect the iron in the blood.
If you have an MRI machine, you can produce a magentic field big enough to effect the iron in the blood, but even then not appreciably so and not enough to effect the movement of blood (the force from your heart is much greater than the magnetic force on the hemoglobin).
(so you are essentially right...I'm just fixing your semantics)
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Note From The Author written by iamthebrillo,
March 17, 2010
The magnetism of blood differs based on the state of the hemoglobin in the blood. Oxygenated hemoglobin, deoxygenated hemoglobin, and methemoglobin all have different magnetic properties. My understanding is oxygenated hemoglobin is diamagnetic, while deoxygenated hemoglobin and methemoglobin are paramagnetic. Diamagnetic materials are repelled by an external magnetic field, and paramagnetic materials are attracted. Ferromagnetism, the important type of magnetism, is not present at all in blood. So in a colloquial sense, blood is non-magnetic. However, theoretically an extremely powerful magnet could have an effect at the atomic level. But as mentioned by cleetus8, the flow of blood provided by the heart is more than powerful enough to overcome this.
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... written by Galadriel,
March 17, 2010
IF magnets could penetrate through to blood vessels and IF a static magnetic field had any effect on blood and IF it were strong enough to have any effect on the circulation of a liquid being moved around by a pump, they still wouldn't *stimulate* blood flow. They'd trap as much blood as they could right under the magnet. They'd stagnate blood flow.
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... written by Rustylizard,
March 17, 2010
@ Galadriel
Good point! You would get a magnetic hickey!
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... written by MadScientist,
March 17, 2010
The magnetic fields do in fact penetrate the skin - in fact the magnetic fields go right through you with almost no disturbance of the field. If that were not the case, then sailors would have had to observe far more stringent measures when working with the magnetic compass.
@Scooter: you need enough iron atoms conglomerated to form a 'magnetic domain'; the hemoglobin molecule has no magnetic domain. Powerful magnetic fields (far more powerful than those quack magnets) do have some effect on the human body but the effect is via disruption of the ion currents in your cells (and between cells) rather than an attraction or repulsion between magnetic substances.
The field passes through skin and bone fairly easily. I held about 10 neodymium magnets from an electric motor in my hand, and was able to stick a crescent wrench on the outer portion of my hand when making a fist. Didn't notice any stimulated blood flow, however. Great fun at parties.
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... written by Galadriel,
March 17, 2010
Wups! I beg your pardon, I spoke imprecisely. As the OP demonstrates in the video, the magnet is not effective at any distance from the magnet itself/with something slim in the way. So the effective distance of the magnet is to what I was referring. (And these are certainly not neodymium!)
An interesting demo might involve using "medical" magnets directly on actual blood.
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... written by MadScientist,
March 17, 2010
@galadriel: You cannot say that a magnet has no effect at a small distance from it - that is simply never true (well, never true in vacuum, air, and many other fluids). The earth's own magnetic field is easily measured even though you cannot readily see its effects unless you have a compass. If I had even a fairly crude magnetometer I would be able to distinguish the field of those weak magnets at a distance of a few meters.
I think the problem with the article is vague wording. "Small distance" is too vague to be of any use for much of anything. Is a small distance an inch, or 10 feet?
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Ah, Science ! written by deavman,
March 19, 2010
I love it when more scientifically precise commenters successively add to the article to finally reach a somewhat succinct yet satisfying level of accuracy.
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... written by Mark P,
March 19, 2010
Most "magnetic" devices use the alternating strips of magnetic material embedded in plastic. Like fridge magnets. Those have ranges in the millimetre range, because the alternating strips cancel out at any further range.
Try it. See how close you have to hold a fridge "magnet" to a compass to get any effect.
To use real magnets, especially rare earth ones, would be to invite disaster. Your supposed "healing properties" would get rather rapidly cancelled out as people sued you for wiping their credit cards and stuffing their watches (magnetising a mechanical watch is a bad move).
Mythbusters tried like hell to demagnetize lots of credit card with all kinds of magnets. Nothing happened. And unless you stuck the magnet right on or next to the watch, nothing would happen either.
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... written by MadScientist,
March 20, 2010
@Mark P: Once again, it is incorrect to make such a statement that alternating magnets only have a 'range' (however you define that) of millimeters. Magnetic fields do *not* 'cancel' - Michael Faraday spent a large part of his life making beautiful illustrations of arrangements of magnets and the corresponding magnetic fields. Neither experiments nor the mathematics and theory support those statements about range and canceling effects.
@Steel Rat: Mythbusters must be doing it wrong. To wipe the information quickly you need to wave the card (or the magnet) so that you have a changing magnetic field which reorients the magnetic domains in the stripe (preferably in a somewhat random fashion). But even without a rapidly changing field, a powerful enough magnet will reorient the domains and render the card useless. I knocked out my bank card and credit card 20 years ago by picking up and moving the magnet from a WW2 era RADAR magnetron. Many credit cards now have a "smart chip" instead and these cannot be easily erased with magnets. Some storage technologies which might be used in smart chips can be erased by magnets but I don't know if cards actually use any of that particular technology.
Well, you'd have to watch the episode and take it up with them. But I hardly think that one episode 20 years ago counts as solid evidence. You're also talking about an electromagnet as opposed to a natural magnet...
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... written by mjh937,
March 21, 2010
I am not sure if this is relevent to credit cards, but I have accidentally rendered hotel card keys inoperative with the magnet in the flap of my cell phone case.
Apparently credit cards use different encoding, since they're reprogrammed often.
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thanks u written by flyfox2100,
July 25, 2010
thanks you,Brandon Peterson,the video can help lots of people,because not everyone know medical,but i don't know the meaning "it still would not stimulate blood flow because the amount of iron in blood is far too small." i love buy shoes online
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Correct me if I'm wrong but I don't think the amount makes any difference. Iron in the blood is non-ferrous.