Amber necklaces and teething babies
|Let’s check the science: Amber teething necklaces – should babies wear them?|
My grandchildren are all past the age when teething is a big problem, but I still shudder when I see small children wearing amber teething necklaces. Surely any parent can see that harnessing a child with such a bauble is inviting a serious strangling or choking incident. You would have to be very desperate, and very certain of the effectiveness to take such a risk, I would think. Is the risk justified? Do these necklaces work?
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The promoters’ arguments – science or red flags?
As I would have expected, some of the claims range from the magical:
•Allows body to heal itself •Radiates soothing energy and absorbs negative energy, thus needs cleansing often •Calms nerves, stimulates intellect •Aligns ethereal and physical energies, cleanses the environment •Success in treating disorders of the kidney and bladder
to the ridiculous:
Amber teething beads work on a simple theory of mild magnetism, which has been found to have the potential to reduce mild pain, such as accompanies teething.
However, many promoters do suggest a plausible mechanism. They claim that amber contains an analgesic substance called succinic acid which is released by the beads in response to the warmth of the child’s body and absorbed through the skin (here, here and here).
Do I see any red flags? Yes, lots of them. I see appeals to ancient wisdom and esoteric energy (here), magical thinking (here), use of anecdotal evidence (here), empty edicts (such as boosting the immune system, here), and pseudoscientific jargon (here).
Initially I was suspicious that the promotion of these necklaces would rely heavily on nonsense about the magical properties of crystals. But most of the sites I found based their claims on the succinic acid mechanism, so it deserves to be checked. Does amber contain succinic acid? Is it released by warmth and absorbed into the body? If so, does it have any physiological effects? Is there any scientific evidence that these beads work? My feeling is that there must be very solid evidence for their effectiveness to justify the risks of choking and strangulation.
The scientific evidence
In my search for evidence, I got off to a great start when I found this posting by Scepticon. It gave me lots of references and analysed the situation very impressively. But I couldn’t take Scepticon’s word as authority, of course. I needed to find primary sources myself.
This is what I managed to discover:
- Baltic amber (the type usually recommended for teething) does contain succinic acid (here). Other types may not.
- I could find no evidence that Baltic amber releases succinic acid at body temperatures. Succinic acid melts at 187 °C but it’s moderately soluble in water. So if it indeed seeps out of the amber, it couldn’t be in molten form. Body temperature (about 37 °C) would be insufficient to melt it. There is a possibility it could be dissolved by sweat.
- Succinic acid is found naturally in our bodies and in many foods, including beer and wine (here). In some countries, it’s allowed as a food additive (number 363). Generally, it’s considered safe (here), although, just as there are no studies on its analgesic effects (see next point), there are none investigating its safety in humans. Interestingly, in bulk it’s regarded as a skin and respiratory irritant, with a risk of serious eye damage (MSDS here). The oral rat LD50 is 2.26 g/kg.
- There is some history of succinic acid being used externally to treat pain. I could find no scientific evidence that it works. Scepticon had the same problem – no studies, no RCTs, nothing. There is a single animal study (here) showing that succinic acid may help in reducing anxiety in mice, but nothing on analgesic effects.
- So, putting it all together, even in the unlikely event that succinic acid is released from the amber, there is no evidence that it is absorbed or has any effect. And even if it does, how sensible is it to allow a completely unregulated dose of a chemical to flow into a child’s body over a long period?
- Apparently, the necklaces are made to break easily so that strangulation risk is reduced. But surely this would increase the risk of choking on the beads. Australian government agencies have warned against allowing children to wear them while unsupervised or sleeping (here, here).
There are plenty of blogs and websites describing personal experiences of parents who have tried amber teething necklaces and have been convinced they are effective (here and here); others have the opposite opinion (here). Needless to say, such anecdotal evidence is worthless, and the examples described in the preceding links are likely to be cases of regression to the mean. In other words, the teething pain eventually gets better. The only way of showing that these necklaces really work would be to conduct proper randomised controlled trials.
This is an easy call. The complete lack of any good evidence that amber necklaces relieve teething pain means that there is absolutely no benefit to offset the risk of wearing them. Remember that in risk assessment, the size of the risk depends on two factors – the likelihood of the event happening, and the severity of the consequences. In this case, one consequence could be death by choking, and in my book, that rules them out completely. I’m disgusted that they are sold in some pharmacies (here).
The Australian Dental Association has suggestions for much less risky methods of reducing teething pain (here). Why would anyone use a ‘treatment’ with such large risks and no supporting evidence?
Update 2013/03/21: At The Conversation (here), Ken Harvey explains that pharmacists are ignoring their own standards by stocking these and other products that are not backed by credible evidence.
Illustration modified from a photo by David Green on flickr.
|This is one of ScienceOrNot’s Let’s check the science series.|