Tryptophan Metabolism and Related Pathways in Psychoneuroimmunology: The Impact of Nutrition and Lifestyle.
Level 5 - mechanism / opinion, no new human data
Narrative review of biological mechanisms without systematic search methodology or primary human data
PubMed 30808841 · doi:10.1159/000496293
What was done
Narrative review evaluating the mechanistic links between tryptophan metabolism, the kynurenine pathway, immune activation biomarkers (such as neopterin), and neurotransmitter systems, as well as the influence of diet and gut microbiota on these pathways.
What was found
The abstract provides conceptual and mechanistic descriptions without quantitative data or specific numerical results. It describes how immune-driven tryptophan breakdown shifts amino acid availability toward neuroactive kynurenine metabolites and how oxidative stress-induced neopterin synthesis links to reduced tetrahydrobiopterin availability for monoamine neurotransmitter synthesis.
Why it matters
Highlights the biochemical intersections among systemic inflammation, metabolic stress, and neuropsychiatric processes, pointing to potential metabolic targets for lifestyle and nutritional interventions.
Limits
As a narrative review, it presents no primary clinical data, quantitative effect estimates, or systematic study search methodology. Specific nutritional interventions and their therapeutic efficacy in humans are not quantified in the abstract.
Cited by
- supports High levels of refined carbohydrates and vegetable oils alter the kynurenine pathway through inflammation and oxidative stress, impacting neurotransmitters including serotonin, melatonin, dopamine, glutamate, and GABA.