Autism spectrum disorders are believed to involve developmental delay of several brain systems and functions. The disorders are characterized by delayed cognitive function, communication skills, social interactions and stereotypical behaviors. Dysfunctions in neurotransmitter systems, including the cholinergic system, have been studied for their potential role in autism development. Neurotransmitters are responsible for communication in the nervous system. Acetylcholine is a neurotransmitter found in the brain that contains the nutrient choline. An acetylcholine deficit is believed to play a potential role in the etiology of autism.
Choline
Choline is an essential nutrient that plays a role in brain development, nerve impulse transmission as a precursor of acetylcholine, cell membrane structure, lipid transport and metabolism, cell signaling, and as a major source of methyl groups, required for many biological functions. Deficient intake during pregnancy and lactation has been shown to limit the child's brain capacity later in life, according to Kelly Dorfman, M.S. Choline deficiencies may decrease acetylcholine availability, which could interfere with brain development and function.
Cholinergic System
Acetylcholine plays an important role in the cholinergic system in the brain. This system is believed to help develop the ability to focus, pay attention, respond to the environment and is involved in memory. It has also been shown to play a role in cognitive development and function. Postmortem studies have found individuals with autism have decreased acetylcholine receptors, which could interfere with the role of this neurotransmitter.
Potential Treatments
Clinical trials of medications that inhibit the metabolism of acetylcholine have had positive outcomes. Acetylcholine esterase inhibitors increase the activity of acetylcholine by preventing breakdown, allowing it to stay in the brain longer. A review published in the "Research in Developmental Disabilities" in 2006 found preliminary evidence these inhibitors help to improve behavior and language. Case studies and animal studies in rats have shown promising results with choline supplementation, but further research is needed. A study is underway at Sheba Medical Center testing the effects of acetylcholine esterase inhibitors and choline supplementation in autistic children.
Choline Sources
The Food and Nutrition Board of the Institute of Medicine determined an adequate intake of choline to be between 125 and 550 mg per day, depending on sex and age. Food sources of choline include beef, particularly liver, eggs, wheat germ, Atlantic cod, milk and peanuts. Autistic individuals are often picky eaters, so choline intake may be inadequate. Talk to your health care provider if you are considering supplementation for you or your child.
References
- "Research in Developmental Disabilities"; Neurochemical Correlates of Autistic Disorder: A Review of the Literature; Kristen S. L. Lam, et al.; 2006
- Neuroscience for Kids; Eric H. Chudler, PhD
- Linus Pauling Institute at Oregon State University: Choline
- Choline and Complex Language Development; Kelly Dorfman, MS; February 2009
- US National Institutes of Health Clinical Trials: Treatment with Acetyl-choline Esterase Inhibitors in Children with Autism Spectrum Disorder
