Title:

A Literature Review on the Effect of Changing Blood Tryptophan Concentration on Mood, in Particular Depression and How Concentration of Ttryptophan can be altered through Diet and Supplements.

Reviewer's comments:

Evidently almost all people experience transiently low moods induced by multiple external and internal factors. Persistent low moods accompanied by low activity and lack of interest in daily activities suggest major depression; a very common mental disorders associated with great burden of disease and most significantly suicide behavior worldwide. Controlling all contributing factors to low moods, and attributing it to only blood Tryptophan changes-serotonin duo is a challenging study designs and task. The authors of this qualitative review addressed this challenge by extensively searching the relevant literature by using medical subject headings (MESH) and limiting the literature search. As a corollary they found many but included 4 most specific, scientifically sound experimental studies which used double-blind randomization, and with good reliability and validity and summarized systematically their results together with some caveats. The tryptophan depletion affects adversely the positive mood of people more among those with recovered depression even on treatment, and also cognitive processes. We suggest the following;

1. In abstract LNAAs should be preceded by large neutral amino acids.

2. From consumers' perspectives, if authors could tailor one more table that shows five more foods and dietary supplements with high and low concentration of tryptophan and commonly used across diverse cultures globally. However, we understand that they have quoted two references for this purpose.

3.  Caveat: Diverse cultures, diverse dietary habits, and diverse rates of low moods and depression need to be addressed either in review or in discussion.

We recommend that this literature review should be published.

Thank You Very Much

In depression yes but not in this area