Gluten exorphins are a group of opioid peptides formed during digestion of the gluten protein. It has been hypothesized that people with autism and schizophrenia have abnormal leakage from the gut of these compounds, which then pass into the brain and disrupt brain function known as the opioid excess theory or a part of leaky gut syndrome. This is partly the basis for the gluten-free, casein-free diet. Two clinical studies of autism patients who followed this diet have found no evidence of benefit. Another found evidence of benefit. Another study suggested the diet may present a greater risk to brain development.
There are four known gluten exorphins with known structure:
Gluten exorphin A5
- Structure: H-Gly-Tyr-Tyr-Pro-Thr-OH
- Chemical formula: C24H37N5O9
- Molecular weight: 599.64 g/mol
Gluten exorphin B4
- Structure: H-Tyr-Gly-Gly-Trp-OH
- Chemical formula: C24H27N5O6
- Molecular weight: 481.50 g/mol
Gluten exorphin B5
- Structure: H-Tyr-Gly-Gly-Trp-Leu-OH
- Chemical formula: C30H38N6O7
- Molecular weight: 594.66 g/mol
Gluten exorphin C
- Structure: H-Tyr-Pro-Ile-Ser-Leu-OH
- Chemical formula: C29H45N5O8
- Molecular weight: 591.70 g/mol
- Autism and Schizophrenia: Intestinal Disorders, Cade, et al., Nutritional Neuroscience, Volume 3, Issue 1 February 2000 , pages 57 - 72
- Popular Autism Diet Does Not Demonstrate Behavioral Improvement, University of Rochester Medical Center, May 19, 2010
- Christison GW, Ivany K (2006). "Elimination diets in autism spectrum disorders: any wheat amidst the chaff?". J Dev Behav Pediatr. 27 (2 Suppl 2): S162–S171. doi:10.1097/00004703-200604002-00015. PMID 16685183.
- Knivsberg, AM, Reichelt, KL, Høien, T, Nødland, M. (2002). "A randomised, controlled study of dietary intervention in autistic syndromes". Nutr Neurosci. 5 (4): 251–61. doi:10.1080/10284150290028945. PMID 12168688.
- Arnold, GL; Hyman, SL; Mooney, RA; Kirby, RS (2003). "Plasma amino acids profiles in children with autism: Potential risk of nutritional deficiencies". Journal of autism and developmental disorders. 33 (4): 449–54. doi:10.1023/A:1025071014191. PMID 12959424.