More carbohydrates in the lower gut may boost brain chemicals linked to the gut microbiome

Increasing hindgut carbohydrate availability leads to a decrease in hindgut aromatic amino acid metabolism and an increase in hypothalamic neurotransmitter expression.

• Higher carbohydrate availability in the hindgut is associated with increased systemic levels of aromatic amino acids.
• This increase in aromatic amino acids correlates with elevated concentrations of central neurotransmitters, such as serotonin and dopamine, in piglets.
• The infusion of starch into the cecum indicates that hindgut microbiota influence neurochemistry dependent on aromatic amino acid metabolism.
• In mice, injections of tryptophan and tyrosine resulted in increased brain levels of these amino acids and enhanced expression of serotonin, dopamine, and neurotrophin BDNF over time.
• In neuronal cells, tryptophan and tyrosine treatments promoted serotonin and dopamine production, respectively, partly through a specific signaling pathway.

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