Of all the whoppers told by the autism bio-med/conspiracy buffs, none may be easier to refute than that chestnut which tells us that the symptoms of mercury poisoning are “exactly the same” as autism. This line is repeated over and over with great certainty, as if it was as obvious as the setting sun.
The lie, and that’s exactly what it is, was jump started in 2000 when Medical Hypothesis, a fringe medical journal, published “Autism: A Novel Form of Mercury Poisoning”. The paper was widely quoted by parents who needed something to blame. Mercury seemed so obvious – it is known to attack the nervous system, and it’s present in thimerosal, and the symptoms of autism present right around the time that infants are immunized. So there ya go – case closed!
When somebody writes “Dandruff: A Novel form of Skin Cancer”, it will also find a home in Medical Hypothesis.
A comparison of the clinical symptoms of mercury poisoning and the diagnostic criteria for autism shows they are quite distinct.
First of all, this handy article in Pediatrics tells us the characteristic motor findings of mercury poisoning are ataxia (gross incoordination of muscle movements) and dysarthria motor speech disorder). Fetal methyl mercury poisoning in severe form also causes spasticity.
In autism, the only common motor manifestations are repetitive behaviors (stereotypies) such as flapping, circling, or rocking. Persons with Asperger syndrome may be clumsy, and hypotonia has been noted in some infants with autism; the frequency of clumsiness and hypotonia in autism spectrum disorders is not established. No other motor findings are common in autism, and indeed the presence of ataxia or dysarthria in a child whose behavior has autistic features should lead to careful medical evaluation for an alternative or additional diagnosis.
Fetal exposure to mercury leads to microcephaly – a small head, as does prenatal exposure to lead, alcohol, PCBs and other neurotoxins. “In contrast”, says Pediatrics, “in autism increasing evidence indicates that head size and, as measured by volumetric magnetic resonance imaging, brain size tends to be larger than population norms.”
I guess that’s where the “novel” part comes in.
17 responses so far ↓
1 Who Remembers Secretin?: Let the Parent Beware When Seeking Treatments for Autism // Dec 23, 2007 at 2:45 am
[...] seek (notoriously) to recast autism as a “novel form of mercury poisoning,” as Autism News Beat reminds us in a recent post. (Safe Minds, an organization which is one of the main advocates for [...]
2 daedalus2u // Dec 23, 2007 at 11:46 am
It is too bad that people with autism don’t have the most important and most diagnostic symptom of mercury poisoning. Without that symptom they don’t have mercury poisoning.
That symptom would be an elevated and toxic level of mercury. Without an elevated level of mercury, how can they have mercury poisoning? It is easy, they can’t, and they don’t.
3 Prometheus // Dec 24, 2007 at 11:50 pm
An interesting point: shortly after the Bernard essay was published in Medical Hypotheses (motto:”We don’t believe in peer review; it inhibits the creative process!”), I had the opportunity to ask each of the authors if they had ever seen mercury poisoning.
None of them had.
Don’t let a lack of information get in the way of a good story.
Prometheus
4 passionlessDrone // Dec 27, 2007 at 3:17 pm
Hi autism news beat -
Knocking down strawmen like the mercury poisoning == autism is simple.
I’m curious if you’ve reviewed this recent study:
http://www.usautism.org/PDF_files_newsletters/Elevated_Brain_Hg_Levels_in_Autism1.pdf
Elevated levels of mercury were found in brains of autistics versus controls (68% greater), though it was a higher trend, but not statistically significant.
What was significant, however, was the relationship between the amount of mercury in the brain and the amount of markers of oxidative stress. Unless you are willing to lobby for increased oxidative stress in the brain, it would seem that reducing the amount of mercury present would be a good place to start.
There was also a significant, relationship in the ratio of mercury and selenium. The less selenium present, the more mercury was present. One quality of selenium is to assist in detoxification of heavy metals. It is almost as if the autistic brains had less ability to detoxify heavy metals than those without such a diagnosis. Go figure that!
I’m curious if you will censor this post.
Anyways, take care.
- pD
5 Kunolacarai // Dec 27, 2007 at 11:53 pm
“Knocking down strawmen like the mercury poisoning == autism is simple.”
It’s only a strawman argument if nobody actually seriously makes the argument. Which was essentially what you did in the second part of your post.
6 passionlessDrone // Dec 28, 2007 at 7:04 am
Hi Kunolacarai –
You are correct, I am not making the argument that mercury poisoning symptoms == autism. Both sides of this debate are mired in gross over simplications, and I feel this is a shame.
I am making the point that the fact that if you don’t meet the criteria of mercury poisoned, this does not mean that you haven’t been adversely affected by mercury. This would seem to be illustrated nicely in the study I provided.
None of the children in this study met the critera as mercury poisoned; however, clinical analysis tells us that mercury was very highly associated with rising levels of oxidative stress markers in the brains of children with autism.
Autism News Beat feels that mercury (or other heavy metals) have no role in the pathology of autism. (If I am incorrect, Autism News Beat, please correct me, and I will apologize). I have simply provided evidence that you can find a relationship of physiological symptoms of autism and mercury, without having to meet the criteria of poisoned.
Perhaps my conclusions are incorrect. (?) Do you have any feelings on it?
Take care!
- pD
7 Kunolacarai // Dec 29, 2007 at 12:15 am
Read the article again. Carefully. Your argument is patently absurd… The effects of mercury poisoning are well-documented, and if your claims were true, then they would be VERY visible in autistic people.
8 autblog // Dec 29, 2007 at 9:36 am
PD: Is it fair to characterize the study that you cite as preliminary, not peer reviewed, and not yet replicated?
9 Anonymous // Dec 31, 2007 at 2:17 pm
It was sponsored by ARI and one of the researchers has strong ties to TACA.
What’s not to like?
10 Prometheus // Jan 2, 2008 at 9:37 am
pD seems to be a bit unclear on the concept of “not statistically significant”.
Given the usual p-value cut-off of 0.05 in biological and medical research, the fact that the selenium and mercury levels did not show a statistically significant difference is quite damning. In short, it means that there’s no reason to suspect that there is a real difference between the two groups in respect to mercury and selenium.
While you might be able to argue that a larger sample might have reached statistical significance, it also might not. As a researcher in biology, I’ve seen a lot of preliminary studies that “approached statistical significance” and yet showed no difference with larger sample sizes.
It’s also interesting to note that one of the authors on this paper – Woody McGinnis – is an author on 4 of the 15 articles in this issue of the journal. Curious, for a fellow with no research grants and no real laboratory facilities to be included in so many papers in a single issue of a journal.
Curious.
So, the article in question actually only found that cerebellar 3-nitrotyrosine levels were elevated in their autistic brain samples (as the title suggests) and that any speculation about selenium and/or mercury is not supported by their data.
Prometheus
11 passionlessDrone // Jan 2, 2008 at 10:47 am
Hi Promotheus –
You are correct! I mistated when I said that the selenium to mercury ratio was statistically signficant. Thanks.
But hold on just a minute, when you say:
“So, the article in question actually only found that cerebellar 3-nitrotyrosine levels were elevated in their autistic brain samples (as the title suggests) and that any speculation about selenium and/or mercury is not supported by their data.”
I’m not sure you are completely correct.
Didn’t we also find a very strong, positive relationship between levels of mercury and levels of 3-HT? This, in my mind, was the most striking thing, as mercury went up, oxidative stress markers also go up. There have frequently been ‘other’ things that could be causing oxidative stress (no doubt there are), but in this case, the relationship between mercury and 3-HT seemed pretty clear, at least to my understanding.
Here is what how I understand it:
“However, there was a positive correlation between cerebellar 3-NT and Hg levels (r=0.7961, p=0.0001).”
I’m told that an r value > .4 tends to be pretty strong stuff when determining strength of a correlation, and that a p value of .0001 indicates that the chance the relationship was random and is less than one in one thousand. But hey, maybe I’m wrong. Have I misread this as well?
As for curious, OK. (?) As for preliminary, it has been noted as such in the abstract. As for not yet repeated, I believe the authors indicate this was the first time such a condition was searched for.
Take care!
- pD
12 autblog // Jan 2, 2008 at 11:38 am
Autism News Beat feels that mercury (or other heavy metals) have no role in the pathology of autism. (If I am incorrect, Autism News Beat, please correct me, and I will apologize).
I believe that there is no solid evidence linking mercury or other heavy metals to autism. I believe that the people who say there is such a link do so despite lack of data, relying instead on unpublished and unreplicated “studies”, conspiracy theories, and cherry-picked evidence.
13 Anonymous // Jan 7, 2008 at 6:59 am
“There was also a significant, relationship in the ratio of mercury and selenium. The less selenium present, the more mercury was present. One quality of selenium is to assist in detoxification of heavy metals. It is almost as if the autistic brains had less ability to detoxify heavy metals than those without such a diagnosis. Go figure that!”
This indicates that Selenium deficiency is the problem, not mercury. Maybe the diets of autisic childrens mothers should be studied?
14 Joseph // Jan 7, 2008 at 1:56 pm
Maybe autistic kids need to use Head & Shoulders more often?
15 Ettina // Jan 7, 2008 at 3:32 pm
“Didn’t we also find a very strong, positive relationship between levels of mercury and levels of 3-HT? This, in my mind, was the most striking thing, as mercury went up, oxidative stress markers also go up.”
And how does this relate to autism? Obviously, mercury poisoning damages your brain. That doesn’t mean it causes autism.
Frankly, I don’t care. If I’m autistic because of mercury poisoning, so what? It doesn’t appear that the mercury poisoning is causing me any real problems.
16 MomNOS // Jan 19, 2008 at 6:12 am
Hey PassionlessDrone –
Maybe a review of the scientific method and steps involved is in order. Preliminary – look it up.
http://en.wikipedia.org/wiki/Scientific_method
17 autblog // Jan 26, 2008 at 9:05 pm
Good one, Mom!
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