Skip Navigation or Skip to Content


Gut Microflora and Autism

Autism is believed to be brought about by a combination of genetic and environmental factors affecting neurodevelopment, signal processing on multiple levels in the nervous system, with behavioral consequences for social interaction and communication. Human physiology is profoundly influenced by resident microorganisms in the gut, having their own genomes and the capability of producing highly damaging neurotoxins, mostly held in check by physical barriers and systems of detoxifying enzymes. Increasingly, it is being recognized that damage to these defensive systems can bring about disease conditions. For example, ulcers, traditionally thought to be caused by internalized stress, are now treated with antibiotics against the bacterium H. pylori. In Crohn’s disease, the complex beneficial role of bacteria in the early instructional phase of the innate immune system is somehow undermined, leading to a compromised bowel lining. Many persons with autism have gastrointestinal issues, such as difficulty in early bowel training, bloating, food allergies, and pain. A Boston Club held on December 13, 2007 brought together experts in the clinical presentation of autism, including those with experience in treating autistic individuals, with experts on the biology of the gut microflora and on sequencing bacterial genomes.

The human gut is populated by over 500 species of microbes having a total mass of around two kilograms. Physiologically, these organisms play crucial roles in breaking down food products and guiding the development of immunological surveillance early in life. Many of these organisms have not yet been identified. New genomic tools are needed to discover all of the strains of bacterial populations in normal populations, and to measure the differences between normal and autistic populations. The biochemical consequences of these differences, against the genetic background of autism — so-called host-pathogen epigenetic relationships — need to be worked out. What neurotoxins are produced by bacteria and what are their targets in the nervous system? These are crucial questions deserving much more attention.

Matthew Anderson, MD, Ph.D., Beth Israel Deaconess Medical Center

Susan Birren, Ph.D., Brandeis University

Timothy Buie, MD, Massachusetts General Hospital

Karolinska Institute Microflora Consortium. Novel Molecular Approach to Screen Human Microflora Comparing Individuals and Groups
Ingemar Ernberg, Karolinska Institute

Albert Galaburda, MD, Beth Israel Deaconess Medical Center

Recent Studies and Perspectives on Gut Microbiology, Probiotics and Autism
Glenn Gibson, Ph.D., The University of Reading

Perinatal Factors Influencing Brain Development: Implications for Autism
Rochellys Diaz Heijtz, Ph.D., Karolinska Institute

Martha Herbert, M.D., Ph.D., Massachusetts General Hospital

Tal Kenet, Ph.D., Massachusetts General Hospital

Microflora interactions with mammalian host metabolism
Jeremy Nicholson, Ph.D., Imperial College London

Possible Role of Neuropeptides and Neuroimmune Interactions in Intestinal Symptoms in Children with Autism
Harry Pothoulakis, MD, University of California Los Angeles

Harland Winter, MD, Harvard Medical School


The Nancy Lurie Marks Family Foundation, Wellesley, MA