Kałużna-Czaplińska · Critical reviews in food science and nutrition 2019 · narrative review · n=?

How important is tryptophan in human health?

Cited 339 times in the scientific literature.

Level 5 - mechanism / opinion, no new human data

Narrative review without systematic methodology or primary empirical data

PubMed 28799778 · doi:10.1080/10408398.2017.1357534 · record verified 2026-08-26

What was done

This paper provides a narrative review synthesizing literature on the biological functions and clinical relevance of tryptophan. It examines tryptophan's role as an essential dietary amino acid, its pathways into serotonin and melatonin synthesis, its diagnostic utility in metabolic disorders, and its potential therapeutic application in psychiatric, cognitive, and neurodegenerative conditions.

What was found

The abstract reports no quantitative data or effect estimates. It outlines qualitative links between tryptophan availability, serotonin pathways, and conditions including depression, sleep disorders, anxiety, cognitive dysfunction, autism spectrum disorder, obesity, and eating disorders, while highlighting tryptophan's role in immune and brain-gut axis function.

Why it matters

It consolidates existing concepts regarding how dietary tryptophan influences neurochemical synthesis and systemic metabolism, emphasizing the importance of adequate dietary intake and monitoring.

Limits

The abstract describes a non-systematic narrative review with no primary data, sample sizes, or quantitative synthesis. Search methodology, study inclusion criteria, risk-of-bias evaluations, and specific dose-response or clinical efficacy metrics are not reported.

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