Derek Lowe just had a blog post out today which is quite skeptical of the mice study: <a href="https://blogs.sciencemag.org/pipeline/archives/2019/05/31/autism-mouse-models-for-the-microbiome" rel="nofollow">https://blogs.sciencemag.org/pipeline/archives/2019/05/31/au...</a>.<p>The salient points are:<p>* Very small N.<p>* Behavioral studies of mice can be very subjective in their own right, so you can definitely get bias, particularly with small N.<p>* There's no generally accepted model of autism in mice. In other words, mice might not even be capable of getting autism in the first place, so saying that "these behaviors in mice correlate with autism in humans" is a bit of a limb.<p>* No measurement of the microbiome in the descendants-of-the-implanted-microbiome (the ones that were actually tested) was demonstrated.<p>So you can come away from the paper with the feeling that they set out to test a hypothesis, interpreted subjective results in the way that best matches the hypothesis, and failed to (or perhaps even purposefully excluded) test for alternate hypotheses that might explain the evidence better.
I think something which should be considered, is that gut bacterial abnormality is very plausibly a consequence of autism, rather than a cause. Selective eating and food refusal occurs in about three quarters of children with ASD, and has been used as a diagnostic criteria (which reinforces the correlation). Poor diversity in nutrition leads to poor biodiversity in the gut flora.<p>That said, poor gut biodiversity could in turn lead to exacerbated presentation of symptoms, due to gut flora's involvement in neurotransmitter systems, interactions with the gut's nervous system, or simply painful intestinal distress.
Derek Lowe is extremely skeptical of this result. the hypothesis might be Ok, but this work in particular isn’t especially convincing:<p><a href="https://blogs.sciencemag.org/pipeline/archives/2019/05/31/autism-mouse-models-for-the-microbiome" rel="nofollow">https://blogs.sciencemag.org/pipeline/archives/2019/05/31/au...</a><p>more criticism:
<a href="https://twitter.com/WiringTheBrain/status/1134129415456264193" rel="nofollow">https://twitter.com/WiringTheBrain/status/113412941545626419...</a>
<a href="https://twitter.com/DrBrocktagon/status/1134339288907206656" rel="nofollow">https://twitter.com/DrBrocktagon/status/1134339288907206656</a>
I am not a microbiome expert but I have always wondered how dynamic is the gut microbiome? For example, maybe I travel for a week and consume a bunch of fast food and drink a bunch of alcohol or I contracted food poisoning. Would my gut microbiome be substantially different than if I followed my regular diet of relatively healthy home made foods? and how long would it take to go back to its default state before I travelled (if ever).
I hope this doesn't provide ammunition for the people pushing making autistic children drink bleach or giving them bleach enemas as a "cure" for autism. Yes, there are such people, and yes, there are parents stupid enough to take their advice and do that to their kids.<p>Since killing bacteria is one of the legitimate functions of bleach, I can see them claiming that their bleach therapy will work by killing off that bad, autism-linked gut bacteria.
If it's true, it will be one of the biggest medical breakthroughs!<p>Shifts like this happen and lead to huge difference in people's lives. Now mostly forgotten, but it was believed that ulcers are caused by stress and food and not bacteria. I have a family member that didn't survive surgery for mistreated ulcer. Then, for me it was a simple matter of taking antibiotics for few weeks.
The biggest issue with a lot of autism research is in how they measure the symptoms of autism. Autistics will often "melt down" or engage in other stereotypical behaviors when the environmental stressors are more severe than what they can deal with through behavior that appears "normal". The more severe the stressors, the more severe and frequent the behavioral deviations.<p>In short, most scientific approaches will often conflate reducing autism with helping people handle their autism better. It's a pretty chronic problem for understanding the disease, but much less impactful for generating practical treatments. Mental healthcare in general doesn't care much whether it reduces the severity of neurodivergence or the distress and socially problematic behavior caused by neurodivergence.
This might sound naive, but isn't the easiest method to reject the hypothesis is to gather data on gut bacteria in people with ASD and those that don't? Wouldn't that be much more direct and explain much more? Or is there some sort of technological or cost limitation to this method?
Call me old-school, but from my perspective, if we are talking about actual <i>evidence</i>, you need exactly one piece of actual evidence, and a case is settled.<p>Maybe this is about <i>hints</i>, not evidence?
There appears to be an increasing amount of evidence linking an unhealthy gut microbiome with various conditions (mostly psychiatric), including a few big ones like Alzheimer's and depression. This has gotten me wondering: how many people might be sick as a consequence of their poor diet? It's probably a good idea to carefully scrutinize your diet as a potential influencing factor if you have a medical condition. Maybe making a few tweaks could end up helping you feel better? In any case, always discuss things with your doctor!<p>Anecdotally, I began to regularly consume more fermented foods (e.g. plain Greek yogurt, kimchi, kombucha, kefir) about 8 or 9 months ago, which helped trigger a cascade of other positive changes and led to gradual but marked improvements to my health.