Tryptophan Amino Acids in Child Autism

This post started as a look at all of the amino acid shifts seen with Autism. One amino acid stood out so I dug deeper into that one.

Note that the results also depend on diet and one should not assume that it applies to every child. Results reported from a single study are often unreliable.

  • .-aminobutyric acid, Lower
  • β-alanine, Lower
  • ammonia Higher
  • aspartic acid, Lower
  • asparagine Higher
  • betaine, Lower
  • citrulline, Lower
  • creatine Higher
  • creatinine, Lower
  • d-threitol Higher
  • glutamate, Lower
  • glycine, Lower, Higher
  • hippurate, Higher
  • isoleucine, Lower, Lower
  • lactate, Lower
  • leucine, Lower, Lower
  • lysine Lower
  • methionine, Lower
  • phenylalanine, Lower, Lower,
  • proline amino acids Lower
  • taurine Lower
  • tryptophan, Lower, Lower, Lower, Lower, Higher, Lower
    • “Elevated BDNF levels and lower tryptophan and KA levels were characteristics of both childhood autism and intellectual disability disorder, whilst elevated tryptophan and lower 5-HT synthesis were hallmarks of Asperger syndrome. ” [2018]
    • “we show that a reduction in the relative abundance of very particular bacterial taxa … namely, bile-metabolizing Bifidobacterium and Blautia species, – is associated with deficient bile acid and tryptophan metabolism in the intestine,[2017]
    • “According to the current literature, abnormal levels of tryptophan entails further irregularities, including serotonin pathway.” [2017]
    • “The vast majority of the results here reported is within usually previously reported reference range (Wishart et al. 2013) for ASD children with vitamins B and magnesium supplementation. Patients without such supplementation have disturbed levels of tryptophan[wild swings]. ” [2017]
  • valine Lower, Lower

 Final regression model to detect Autism comprised of urinary free valine and tryptophan [2018].

Quick look at 2 autism children with multiple samples:

Only once was it at or above the typical (median) level
Usually below the typical (median) level

Bottom Line

Vitamins B and magnesium supplementation has been studied with positive effects. I have not located any human studies on using valine and tryptophan supplements.

“Our findings demonstrate mouse sociability and brain 5-HT turnover are reduced by acute TRP depletion, and can be enhanced by TRP supplementation. “[2015]

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