Increased gut permeability or leaky gut has been an important feature of quite a lot of autism research in 2013. Referencing issues with the delicate barrier which separates the contents of the gastrointestinal (GI) tract from the wider body environment, elevated gut permeability as being a feature in some cases of autism is slowly moving out of the research fringes into something altogether more mainstream.
This statement is based on both investigations of people with autism and also recent results from two quite well-known mouse models of autism also potentially presenting with permeability issues.
The paper by Dalton and colleagues* further adds to the conversation about issues with gut permeability and autism observing that 8% of children with autism in their cohort presented with gut permeability measures outside of recognised reference ranges. Further, that 6% of children with special educational needs (SEN) (but not autism) also presented with potential gut permeability issues too.
Based on a commonly used measure of gut permeability involving the consumption of two sugars, mannitol and lactulose, and measurement of the urinary output of those sugars, researchers were able to calculate the ratio of excreted sugars to form an opinion on the possible presence of increased gut permeability. Their chosen method of urine analysis for the sugars involved one of the more gold-standard analytical measures (mass spectrometry) thus providing greater conformational powers than that reported in previous studies.
Although no significant group differences were found in gut permeability measures in those diagnosed with autism compared with those with SEN, the identification of a possible subgroup of children and young adults with such issues is potentially important. Not least that one child with autism with a more definite pathological gut permeability result also presented with undiagnosed and asymptomatic coeliac disease (an autoimmune condition managed by use of a gluten-free diet). The link between increased gut permeability, autism and diets devoid of gluten (the protein found in various cereal produce) has been discussed in other research in this area.
Gaps remain in our knowledge of how GI issues including leaky gut are associated with cases of autism. Further evidence is required to understand whether gut permeability issues represent a central part of the onset and presentation of at least some cases of autism, or merely an interesting correlation with only a chance association. Whether also amelioration of permeability issues may have knock-on effects in relation to behaviour or more general health and wellbeing, represents a next stage in this important area of autism research.
* Dalton N. et al. Gut Permeability in Autism Spectrum Disorders. Autism Research. 2013. Dec 12. 10.1002/aur.1350
Further commentary on this study can be found at: http://questioning-answers.blogspot.co.uk/2013/12/gut-permeability-in-teens-with-autism.html