Six children with autistic spectrum disorders and persistent diarrhea for many years received 500 mg/day of glucosamine spread over the morning and evening meal for 30 days. The children were already being managed with interventions such as avoidance of dairy products and gluten, and use of probiotics and nutritional supplements; these interventions remained unchanged during the trial. In 5 of the 6 children, diarrhea disappeared during glucosamine supplementation.

Comment: Many autistic children appear to have food sensitivities, which can adversely affect gastrointestinal and brain function. Gluten contains a lectin that is believed to be incompletely broken down in the gut to release an enkephalin-like peptide, which appears to be associated with behavioral and gut disorders in some autistic children. N-acetylglucosamine can block wheat lectin, which led the investigator to consider the possibility that glucosamine would have a similar effect.

Although there was no control group, the results seem impressive, since the children had long-standing diarrhea that had not been controlled by other interventions. The beneficial effect of glucosamine does not seem to be attributable to an interference with wheat lectin, because the children were already avoiding gluten-containing foods. It is possible that glucosamine inhibits the effect of other food-derived peptides or lectins on the gastrointestinal tract.

Danczak E. Glucosamine and plant lectins in autistic spectrum disorders: an initial report on 6 children with uncontrolled diarrhoea. J Nutr Environ Med 2004;14:327-330.