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Mood effects of the amino acids tryptophan and tyrosine: 'Food for Thought' III.
Acta Psychiatr Scand. 2011 Dec; 124(6):417-26.AP

Abstract

OBJECTIVE

Reflecting increased scientific interest in any nutritional contribution to the onset and treatment of mood disorders, we overview research into two neurotransmitter precursors - the amino acids tryptophan and tyrosine - particularly examining whether any deficiency increases risk to depression and whether those amino acids have any antidepressant properties.

METHOD

The theoretical relevance of the two amino acids was overviewed by considering published risk and intervention studies, technical papers and reviews.

RESULTS

There is some limited evidence, suggesting that depressed patients, especially those with a melancholic depression, have decreased tryptophan levels. Whether such findings reflect a causal contribution or are a consequence of a depressed state remains an open question. There is a small database supporting tryptophan preparations as benefitting depressed mood states. There is no clear evidence as to whether tyrosine deficiency contributes to depression, while the only randomized double-blind study examining tyrosine supplementation did not show antidepressant benefit.

CONCLUSION

Acute tryptophan depletion continues to provide a research tool for investigating the relevance of serotonin to depression onset. There is limited evidence that tryptophan loading is effective as a treatment for depression through its action of increasing serotonin production. Most clinical studies are dated, involve small sample sizes and/or were not placebo controlled. The development of the new serotonin reuptake inhibitor drugs seemingly signalled an end to pursuing such means of promoting increased serotonin as a treatment for depression. The evidence for tyrosine loading promoting catecholamine production as a possible treatment for depression appears even less promising, and depletion studies less informative.

Authors+Show Affiliations

School of Psychiatry, University of New South Wales, Black Dog Institute, Randwick, Sydney, NSW, Australia. g.parker@unsw.edu.auNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't
Review

Language

eng

PubMed ID

21488845

Citation

Parker, G, and H Brotchie. "Mood Effects of the Amino Acids Tryptophan and Tyrosine: 'Food for Thought' III." Acta Psychiatrica Scandinavica, vol. 124, no. 6, 2011, pp. 417-26.
Parker G, Brotchie H. Mood effects of the amino acids tryptophan and tyrosine: 'Food for Thought' III. Acta Psychiatr Scand. 2011;124(6):417-26.
Parker, G., & Brotchie, H. (2011). Mood effects of the amino acids tryptophan and tyrosine: 'Food for Thought' III. Acta Psychiatrica Scandinavica, 124(6), 417-26. https://doi.org/10.1111/j.1600-0447.2011.01706.x
Parker G, Brotchie H. Mood Effects of the Amino Acids Tryptophan and Tyrosine: 'Food for Thought' III. Acta Psychiatr Scand. 2011;124(6):417-26. PubMed PMID: 21488845.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Mood effects of the amino acids tryptophan and tyrosine: 'Food for Thought' III. AU - Parker,G, AU - Brotchie,H, Y1 - 2011/04/12/ PY - 2011/4/15/entrez PY - 2011/4/15/pubmed PY - 2012/3/15/medline SP - 417 EP - 26 JF - Acta psychiatrica Scandinavica JO - Acta Psychiatr Scand VL - 124 IS - 6 N2 - OBJECTIVE: Reflecting increased scientific interest in any nutritional contribution to the onset and treatment of mood disorders, we overview research into two neurotransmitter precursors - the amino acids tryptophan and tyrosine - particularly examining whether any deficiency increases risk to depression and whether those amino acids have any antidepressant properties. METHOD: The theoretical relevance of the two amino acids was overviewed by considering published risk and intervention studies, technical papers and reviews. RESULTS: There is some limited evidence, suggesting that depressed patients, especially those with a melancholic depression, have decreased tryptophan levels. Whether such findings reflect a causal contribution or are a consequence of a depressed state remains an open question. There is a small database supporting tryptophan preparations as benefitting depressed mood states. There is no clear evidence as to whether tyrosine deficiency contributes to depression, while the only randomized double-blind study examining tyrosine supplementation did not show antidepressant benefit. CONCLUSION: Acute tryptophan depletion continues to provide a research tool for investigating the relevance of serotonin to depression onset. There is limited evidence that tryptophan loading is effective as a treatment for depression through its action of increasing serotonin production. Most clinical studies are dated, involve small sample sizes and/or were not placebo controlled. The development of the new serotonin reuptake inhibitor drugs seemingly signalled an end to pursuing such means of promoting increased serotonin as a treatment for depression. The evidence for tyrosine loading promoting catecholamine production as a possible treatment for depression appears even less promising, and depletion studies less informative. SN - 1600-0447 UR - https://www.unboundmedicine.com/medline/citation/21488845/Mood_effects_of_the_amino_acids_tryptophan_and_tyrosine:_'Food_for_Thought'_III_ L2 - https://doi.org/10.1111/j.1600-0447.2011.01706.x DB - PRIME DP - Unbound Medicine ER -