Impaired Carbohydrate Digestion in Children with Autism

[RustyJ]

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

Brent L. Williams1, Mady Hornig1, Timothy Buie2, Margaret L. Bauman3, Myunghee Cho Paik4, Ivan Wick1, Ashlee Bennett1, Omar Jabado1, David L. Hirschberg1, W. Ian Lipkin1

Abstract

Gastrointestinal disturbances are commonly reported in children with autism, complicate clinical management, and may contribute to behavioral impairment. Reports of deficiencies in disaccharidase enzymatic activity and of beneficial responses to probiotic and dietary therapies led us to survey gene expression and the mucoepithelial microbiota in intestinal biopsies from children with autism and gastrointestinal disease and children with gastrointestinal disease alone.

Ileal transcripts encoding disaccharidases and hexose transporters were deficient in children with autism, indicating impairment of the primary pathway for carbohydrate digestion and transport in enterocytes. Deficient expression of these enzymes and transporters was associated with expression of the intestinal transcription factor, CDX2.

Metagenomic analysis of intestinal bacteria revealed compositional dysbiosis manifest as decreases in Bacteroidetes, increases in the ratio of Firmicutes to Bacteroidetes, and increases in Betaproteobacteria. Expression levels of disaccharidases and transporters were associated with the abundance of affected bacterial phylotypes.

These results indicate a relationship between human intestinal gene expression and bacterial community structure and may provide insights into the pathophysiology of gastrointestinal disturbances in children with autism.

http://www.plosone.org/article/info...onid=C335DF30F9D78C2F7E964FEDC6C0C4D9.ambra02

 

[alex3619]

Hi, this makes a lot of sense. Alterations of transporter expression or function will alter sugar levels in the gut, and different sugar levels are likely to be more optimal to different species/communities of bacteria. Bye, Alex

 

[RustyJ]

One of the authors of the study is Ian Lipkin. Seems a divergence from his virus hunting. Or is it?

 

[Glynis Steele]

Ian Lipkin has been involved with autism in the past, I believe he was involved in the Autism Birth Cohort Study, and also has said there is no connection between the MMR vaccine and autism.

 

[Glynis Steele]

Reading through this study, it says there is a decrease in Bacteroidetes and an increase in the Firmicute/Bacteroidetes ratio and increased cumulative level of Firmicutes and Proteobacteria.

The Firmicutes group is typically divided into the Clostridia, which are anaerobic, and Bacilli. Lactobacilli have been found to be increased in autism, as have Clostridia, in previous studies.

I believe that carbohydrates directly impact autistic behaviours, due to bacterial overgrowth of these type of bacteria, and their ability to ferment carbs, which is why carb restriction diets such as GF/CF are so successful, though the general belief is the opiod effect of these foods.

 

[RustyJ]

Reading through this study, it says there is a decrease in Bacteroidetes and an increase in the Firmicute/Bacteroidetes ratio and increased cumulative level of Firmicutes and Proteobacteria.

The Firmicutes group is typically divided into the Clostridia, which are anaerobic, and Bacilli. Lactobacilli have been found to be increased in autism, as have Clostridia, in previous studies.

I believe that carbohydrates directly impact autistic behaviours, due to bacterial overgrowth of these type of bacteria, and their ability to ferment carbs, which is why carb restriction diets such as GF/CF are so successful, though the general belief is the opiod effect of these foods.

So to redress this issue, besides carb restriction, what else could we do, provided of course this is an issue for ME/CFS. Is taking Clostridia a viable treatment - I don't know much about it. Anything else?

 

[Glynis Steele]

Clostridia is one of the bad guy's, I think. Other bacterial overgrowth's have been implicated in CFS. Ideally a GI would be the best person to see, but the study involved in CFS was a small one, so it is doubtful whether a GI would take it seriously, and investigate any possible overgrowth.

 

[RustyJ]

Clostridia is one of the bad guy's, I think. Other bacterial overgrowth's have been implicated in CFS. Ideally a GI would be the best person to see, but the study involved in CFS was a small one, so it is doubtful whether a GI would take it seriously, and investigate any possible overgrowth.

Sorry, misread your previous post, got confused about which bacteria was which (lol). Thanks for the extra info btw. I don't really intend to see a GI, but may try carb restriction diet for a while. I don't think I would keep at it for long. But some posters have had success with low carb diets and I guess this study has piqued my interest.

 

[Glynis Steele]

Hi RustyJ,

Working out which bacteria are which hurts my head! Maybe try gluten free first, and see how you go. At least that way, it's not too restricting.

BW

Glynis x

 

[RustyJ]

Hi Glynis, went gluten free a couple of years ago (still GF). Helped greatly. Surprisingly my gall bladder trouble went away immediately. Cheers.

 

[Glynis Steele]

This is related to the same study, from Science Daily, comment at the bottom by Ian Lipkin.

ScienceDaily (Sep. 18, 2011) Researchers at the Center for Infection and Immunity (CII) at Columbia University's Mailman School of Public Health and at the Harvard Medical School report that children with autism and gastrointestinal disturbances have altered expression of genes involved in digestion. These variations may contribute to changes in the types of bacteria in their intestines.


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Autism, which is defined by impairments in verbal and non-verbal communication, social interactions, and repetitive and stereotyped behaviors, affects approximately 1% of the population. Many children with autism have gastrointestinal problems that can complicate clinical management and contribute to behavioral disturbances. In some children, special diets and antibiotics have been associated with improvements in social, cognitive and gastrointestinal function.

The investigators found that children diagnosed with autism and gastrointestinal disturbances have abnormalities in levels of genes for enzymes that break down sugars and for molecules that transport them from the lumen of the intestine into the blood. These variations were also associated with changes in the bacterial composition of the intestine.

The researchers examined biopsies from 22 patients, 15 diagnosed with autism and seven typically developing children. They used real-time PCR to measure gene expression and genetic sequencing techniques to characterize the bacteria present in the intestines of each child.

Brent Williams, PhD, research scientist at CII and first author of the study, noted that, "whereas others have looked at bacterial composition of feces, our group was the first to characterize mucosal communities and to link findings to expression of genes important in carbohydrate metabolism and transport."

"The findings are consistent with other research suggesting that autism may be a system-wide disorder, and provide insight into why changes in diet or the use of antibiotics may help alleviate symptoms in some children," added Mady Hornig, MD, Director of Translational Research at the Center for Infection and Immunity.

"Although caution in interpretation is indicated because the sample size is small, our findings nonetheless provide a framework for developing and testing new hypotheses concerning the role of malabsorption and microflora in autism and related disorders," said Ian Lipkin, MD, Director of the Center for Infection and Immunity.