In the first systematic review on this topic, researchers at the University of Texas report on growing consistent evidence that traumatic brain injury (TBI) changes the gut microbiome. Evaluating these changes, they conclude, will be a fertile ground for new therapeutic interventions.

In earlier posts we reported on evidence of neurotransmitters in the gastrointestinal tract and the importance of the “gut-brain axis” as a “bidirectional communications network.” Evidence has shown that approximately 90% of serotonin and 50% of dopamine is produced in the gut and that numerous bacterial species play a role in producing and consuming neurotransmitters in the gut.

One of the studies highlighted in the review showed a general overall pattern in head injury cases with the amount of beneficial bacteria decreasing over time and the amount of pathogenic bacteria increasing over time. This can lead to gut permeability and increased risk for additional deleterious conditions, including “rapid weight loss, negative nitrogen balance and heightened whole-body protein breakdown.”

This review highlights the importance of monitoring metabolic changes following TBI and further investigating effective interventions to prevent these changes.