letter to the editor re: Bradstreet 2010

Alternative Medicine Review 2010;15:187


Bradstreet and coworkers recommended testing the blood of autistic children for ammonia (a sign of oxidative stress and mitochondrial dysfunction), noting high blood ammonia is more toxic to children than adults, and can lead to permanent CNS damage [1]. Considerable evidence supports Bradstreet’s concern. Cohen detected high blood ammonia and GABA in an eight-year-old autistic boy [2]. Filipek et al. subsequently found blood ammonia high in many of 100 children with autism [3]. Wakefield et al proposed intestinal bacteria in these children generate more ammonia than the impaired liver can clear, allowing ammonia to reach the brain, where it releases the excitatory transmitter glutamate, and GABA to suppress the excitation [4].

Ammonia causes astrocytes to swell, which can compress the lumen of brain capillaries by nearly half [5]. Accumulation of ammonia in patients with chronic liver disease redistributed blood from cortical to subcortical regions of the brain [6]. Helt et al. suggested immune reactions causing astrocytes to swell may explain reduced brain blood flow in children with autistic disorders [7]. Astrocytes swell in response to a variety of neuro-toxins, including organic mercury [e.g. thimerosal] and excessive glutamate, as well as oxidants and antigens [5]. Swelling of astrocytes is compensated by high levels of taurine, the free amino acid that carries water out of brain tissues (among other functions). Ammonia releases more taurine from brain tissues into interstitial fluid than any other amino acid [8]; taurine was the amino acid most wasted or deficient in urine in more than half of a group of autistic children [9].

Drawing blood from autistic children may require sedation, however, according to Bradstreet et al; urinary tests for ammonia appear less reliable. One alternative may be taurine supplementation – deficiency of intracellular molecules like magnesium and taurine is often best measured by the response to supplements. Three grams/day of taurine (and even much higher levels) have shown no adverse effects in man [10]. The Autism Research Institute recommended 250-500 mg/day of taurine for children with autism, 2 g/day for adults and adult-sized children [11].

Ammonia and other neurotoxins may explain several characteristics of autism: (a) swelling and proliferation of astrocytes, (b) reduced brain blood flow (c) high blood GABA, (d) seizures, and (e) loss of taurine in urine.

Peter Good

Autism Studies

La Pine, OR

  1. 1.Bradstreet JJ, Smith S, Baral M, Rossignol DA. Biomarker-guided interventions of clinically relevant conditions associated with autism spectrum disorders and attention deficit hyperactivity disorder. Altern Med Rev 2010;15:15-32. pdf at http://www.thorne.com/altmedrev/.fulltext/15/1/15.pdf

  2. 2.Cohen BI. Infantile autism and the liver: a possible connection. Autism 2000;4;441-442.

  3. 3.Filipek PA, Juranek J, Nguyen MT, et al. Relative carnitine deficiency in autism. J Autism Dev Disord 2004;34:615-623.

  4. 4.Wakefield AJ, Puleston JM, Montgomery SM, et al. Review article: the concept of entero-colonic encephalopathy, autism and opioid receptor ligands. Aliment Pharmacol Ther 2002;16:663-674.

  5. 5.Aschner M, Allen JW, Kimelberg HK, et al. Glial cells in neurotoxicity development. Annu Rev Pharmacol Toxicol 1999;39:151-173.

  6. 6.Felipo V, Butterworth RF. Neurobiology of ammonia. Prog Neurobiol 2002;67:259–279.

  7. 7.Helt M, Kelley E, Kinsbourne M, et al. Can children with autism recover? If so, how? Neuropsychol Rev 2008;18:339-366.

  8. 8.Albrecht J, Schousboe A. Taurine interaction with neurotransmitter receptors in the CNS: an update. Neurochem Res 2005;30:1615-1621.

  9. 9.Pangborn JB. Introduction to the diseases of autism and laboratory testing options. In: Pangborn JB, Baker SM. Biomedical Assessment Options for Children with Autism and Related Problems. San Diego, CA: Autism Research Institute; 2002: 1-130.

  10. 10. Shao A, Hathcock JN. Risk assessment for the amino acids taurine, L-glutamine and L-arginine. Regul Toxicol Pharmacol 2008;50:376-399.

  11. 11.Autism Research Institute. Treatment Options for Mercury/Metal Toxicity in Autism and Related Developmental Disabilities: Consensus Position Paper. February 2005. pdf at: http://www.autism.com/pdf/providers/heavymetals.pdf (accessed June 14, 2010)