Friday, September 23, 2011

Carbohydrates, Gut and Autism

If you haven't already, go read the latest Psychology Today post about Alzheimer's and High Blood Sugar and Alzheimer's and Omega3s.  Page views on my Psychology Today posts help support the paper, toner, textbook, and time that goes into Evolutionary Psychiatry.

Jamie sent me this link from PLOS1 (which, admittedly, is not the Rolls Royce of journals, but does have some interesting stuff every now and again):

Impaired Carbohydrate Digestion and Transport and Mucosal Dysbiosis in the Intestines of Children with Autism and Gastrointestinal Disturbances

Hmm. The text is very large and doesn't seem amenable to editing.  One more reason to move over to wordpress…

So y'all have heard of the GAPS diet, right?  Natasha Campbell-Mcbride is a doctor who had a kid with autism.  I haven't read her book yet, but the general theory is that folks with certain issues with gut microbiota and carbohydrate malabsorption will end up with psychological/psychiatric symptoms, including autism.  Dr. Campbell-McBride had great success with this approach, as, apparently, do many others.

In this PLOS1 paper, patients with autism and patients with GI disturbances were examined for different carbohydrate malabsorption.

Kids with autism often have gastrointestinal problems (survey studies report comorbidities of 9-91%, which isn't all that useful a percentage spread, but certainly given clinical experience and thinking about autistic kids I know in the community, higher seems more likely than lower).  Pathologic findings of gut issues in autistic kids include gastritis, esophagitis, inflammatory markers at the gut lining, gut lymphatic system hyperplasia, increased intestinal permeability, abnormal gut microbiota findings, increased enzyme secretion, and carbohydrate malabsorption.  Indeed, autistic children with severe gastrointestinal symptoms are more likely to have severe autistic symptoms (1).

So what happens if you don't have efficient digestion of disaccharides, for example, for whatever reason (damage to gut, unlucky genes, other illness)?  Well, any carbohydrate that goes undigested will float down and feed the hungry masses of gut bacteria.  This feeding can result in bloating, discomfort, diarrhea, and proliferation of pathogenic bacteria, which can presumably affect both inflammation and behavior.

The researchers from the latest studies biopsied the intestines of autistic children with gastrointestinal symptoms (AUT-GI), finding the following (among other things:)

Pyrosequencing analysis of mucoepithelial bacteria revealed significant multicomponent dysbiosis in AUT-GI children, including decreased levels of Bacteroidetes, an increase in the Firmicute/Bacteroidete ratio, increased cumulative levels of Firmicutes and Proteobacteria, and increased levels of bacteria in the class Betaproteobacteria...
Metabolic interactions between intestinal microflora and their hosts are only beginning to be understood. Nonetheless, there is already abundant evidence that microflora can have system-wide effects and influence immune responses, brain development and behavior.

When there is a devastating illness with only supportive treatment, a harmless intervention, such as adjusting the types of carbohydrates in the diet (this will not be a completely "paleo" intervention - sweet potatoes, for example, are off limits on GAPS I believe - I will post some more when I get the book), seems to be an approach that ought to be supported and attempted.  Sure, it might not help everyone, but what is there to lose?


  1. What is there to lose? What is childhood without animal crackers?! I used to bite their heads off first, it is cherished memory! But I suppose neurological diseases sound pretty bad too. Poor kids.

    Anyway, this all makes sense to me. It seems like everyone knows someone with an autistic child these days, I hope GAPS can help. There are certainly good testimonials.

  2. I would highly recommend reading the GAPS book, as well as Breaking the Vicious Cycle by Elaine Gottschall. My child was a miracle responder to the SCD so I'm pretty partial to these books. But what gets REALLY interesting is that the originator of the diet was Dr. Sidney Haas who developed the diet to cure Celiacs in the 1920's. Which it appeared to do. In his book "Management of Celiac Disease" he describes odd behavior noticed in the 1920s and 1930s by various physicians in their more severe ped gi patients. Behavior which cleared up on the diet. The behavior descibed sounds an awful lot like autism.

  3. Thanks Dr. Deans. I'm glad to see that more credibility is being attributed to the GAPS school of thought.

    I'm pondering on the question: Is it at all possible for anticholinergics to mask symptoms of leaky gut or celiac? In the absence of symptoms of IBS/Leaky Gut as a result of treatment with a medication with anticholinergic effects, and hence the tolerance of foods previously problematic, should one still stick to a diet designed for Leaky Gut/IBS?

    Thanking you.

  4. I am the mother of an autistic son and I am pursuing treatments based on the McCandless/Bock approach (which is often referred to as DAN!, for Defeat Autism Now!).

    I am so happy that you seem to have an interest in this and are posting your insights about papers as they come out.

  5. Excellent blog! I've been following for months now and love your articles.

    I'm involved in the field of Functional Neurology and in research with kids with Learning Disabilities.

    We do see dysbiosis, malabsorption, and leaky gut in these kids frequently. With the connection between leaky gut and the blood brain barrier, it's easy to connect the global inflammation seen on brain scans with glial activation from gut proteins getting into the system and setting off autoimmune reactions in the brain.

    However, we also see under-connectivity in some parts of the brain (the right hemisphere in autism) and over-connectivity in other parts which doesn't fit with something that effects the brain globally.

    Another theory from Dr. Robert Melillo ( ) is that the under-connective brain regions came first. Followed by increased sympathetic tone globally due to unequal sympathetic inhibition through the PMRF pathway. The higher sympathetic tone inhibits digestive enzymes which leads to the all the other problems mentioned.

    Just food for thought. Keep up the great work! :)


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