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In particular older people (i.e. 30+) are getting diagnosed just now because doctors previously didn't know what they were looking for.
How and if people got autism before processed foods?
The article isn't saying that the only cause of autism is the preservative. It is suggesting maybe part of the increase is due to this preservative.
Although people died before cars existed, it doesn't mean that cars aren't the cause of some deaths today.
I'm no doctor or biochemist but propionic acid seems way too natural and common a chemical to be a likely cause. It's not the first preservative I'd investigate either. For example, why not investigate benzoic acid?
Even if this isn't rock-solid I'd rather see a backlash against processed foods than against vaccines.
The preservative in question is propionic acid (PPA): > In the current study, Saleh Naser, PhD and her team at UCF found that when neural stem cells were exposed to high levels of PPA, the neurons incurred multiple changes resulting in cellular damage and inflammation. One of the major effects of PPA they noted was the overproduction of glial cells, the protective outer cells making up the sheath covering neurons, wi…
This is very preliminary speculative science that shouldn't be oversold.
I'm no doctor or biochemist but propionic acid seems way too natural and common a chemical to be a likely cause. It's not the first preservative I'd investigate either. For example, why not investigate benzoic acid?
>Previous studies have demonstrated increased levels of PPA, a short chain fatty acid (SCFA), in the feces of children with ASD; we also know that the gut microbiome in these children is also quite distinct in terms of the type of bacteria that inhabit their intestines.
>Clostridia, Bacteriodetes, and Desulfovibrio bacteria are unique to patients with ASD. What’s interesting is that these bacteria are also known to be fermenters of carbohydrates that produce PPA, and other SCFAs as well. Ironically, while PPA is the most common compound produced by bacteria in ASD patients, it is also widely used in the food industry as a preservative due to its ability to inhibit grown of fungi (mold).
So following up I found an article on the etiological history of the PPA link [0]. From that article, there was a 2008 study of PPA injections in rats (spoiler, observed to cause ASD-like symptoms)[1], and a case study in 2012 of an ASD child with propionic acidemia, a rare metabolic condition that affects PPA metabolism [2], which led to more recent studies establishing a connection between behavioral disruptions and propionic acidemia, even in children who did not meet the diagnostic criteria for ASD [3].
ASD can also exhibit GI tract issues like constipation and IBS as symptoms, which would have supported some kind of gut microbiome hypothesis. Regarding what you're saying about how common PPA is, one research group speculates a "two-hit" mechanism behind ASD:
>Al-Owain’s group suggests that PA may thus act as one of the drivers of developing ASD under the two-hit model of ASD pathology, which posits that two separate factors must be present before ASD is developed. Under this model, one problem—such as PA in isolation—is insufficient to cause ASD, but when paired with another problem—such as another metabolic disorder affecting the gut-brain axis, like biotinidase deficiency—the combined detrimental effects of the two pathologies can cause ASD.
[0]: https://www.foundationalmedicinereview.com/blog/the-link-bet...
[1]: https://www.ncbi.nlm.nih.gov/pubmed/18395759
[2]: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3573175/pdf/978...
[3]: https://www.sciencedirect.com/science/article/pii/S109671921...
Interesting how it’s not listed for food use in EU: https://echa.europa.eu/substance-information/-/substanceinfo...
The preservative in question is propionic acid (PPA): > In the current study, Saleh Naser, PhD and her team at UCF found that when neural stem cells were exposed to high levels of PPA, the neurons incurred multiple changes resulting in cellular damage and inflammation. One of the major effects of PPA they noted was the overproduction of glial cells, the protective outer cells making up the sheath covering neurons, wi…
I was wondering about that, too. Inspired in part by articles like this: https://www.scientificamerican.com/article/the-root-of-thoug...
Looks like in 2018 there's a few [0] interesting [1] papers [2] on the link between senescent glial cells and neurodegeneration, which I think would support a theory of glial cells playing some role in cognition. Seems to be a fairly active area of research.
[0]: https://www.nature.com/articles/s41586-018-0543-y
[1]: https://www.researchgate.net/profile/Jay_Penney/publication/...
[2]: https://www.sciencedirect.com/science/article/pii/S089662731...
The preservative in question is propionic acid (PPA): > In the current study, Saleh Naser, PhD and her team at UCF found that when neural stem cells were exposed to high levels of PPA, the neurons incurred multiple changes resulting in cellular damage and inflammation. One of the major effects of PPA they noted was the overproduction of glial cells, the protective outer cells making up the sheath covering neurons, wi…
Were the "high levels" of PPA food level, or 100x total human lifetime exposure? This is very preliminary speculative science that shouldn't be oversold.
Regarding the second half of your comment, I'll cite from the etiology article I linked:
> In the concluding sentences of their analysis, Witters and Debold make their strongest argument for the connection between propionic acid and ASD by observing that, given the rates of PA [proprionic acidemia] and of ASD occurrence in the general population, the probability of there being no link between the two pathologies is 4.34 in 10 trillion. Put differently, comorbid incidences of PA and ASD are far more common than should be expected between two unrelated diseases, meaning that there is most likely a link between the two.