Title: A cross-sectional study observing the association of psychosocial stress and dietary intake
with gut microbiota genera and alpha diversity among a young adult cohort of black and white
women in Birmingham, Alabama
Version: 2 Date: 18 Nov 2023
Reviewer:  Rebecca J. Solch
Reviewer's report:
Manuscript Review:
A cross-sectional study observing the association of psychosocial stress and dietary intake with
gut microbiota genera and alpha diversity among a young adult cohort of black and white women
in Birmingham, Alabama
Article and Review Summary The authors assessed the gut microbiota composition and diversity
in African American and European Women. Interestingly, the authors found lower ASV count,
Blautia abundance, and that various psychosocial stress and dietary variables correlated with
gut microbiota abundance. This study provides interesting findings that extend our current
understanding of gut microbiota composition in women and what may be modulating the gut
microbiota. The authors are commended for completing this interesting study. However, some
questions and concerns remain. Additional specific comments, suggestions, and queries are
below.
Abstract:
- Line 27: “Mediation analyses assessed the mediating role…”, “Mediating” could be taken out
as it sounds redundant.
Introduction
- Line 45: add “disease” after Alzheimer’s disease
- Line 82, fix citations – formatting seems off throughout. The citations in this form should
follow after the “.”
- The rationale starting on line 87, although thorough, is very long. Would read better if more
succinct. Could potentially end after the end of the sentence on line 97.
Methods
- Line 130: Was the use of antibiotics considered for exclusion criteria?
- Line 138: What is the rationale for choosing the luteal phase vs other phases?
- Line 149: Please provide a citation for young adults ranging from 18 to 45. 45 seems to be
closer to middle age.
- Line 157: was the time of day accounted for cortisol measurement? Were they collected in
the morning or throughout the day? Cortisol levels fluctuate throughout the day and peak in the
morning.
- Microbiota analysis
o Line 161: provide kit information for microbiota analysis.
o What program was used to conduct microbiota analyses
o This study would be strengthened by including other measurements of alpha diversity
including Shannon, Simpson, and chao1. Additionally, measurements of Beta-diversity would
provide great insight into any compositional differences between races.
o Not required, but would also strengthen this manuscript is to determine if there are differences
between genera that are not the most abundant. LEfSe (Linear discriminant analysis Effect
Size) analysis or another type of analysis assessing ASVs between groups would be interesting.
There may be differences in race in more rare taxa that may be related to stress or other dietary
measurements.
- Line 188: add quotations around the italicized sentence.
- Lines 193-195- if this is included, this would read better at the start of the paragraph.
Results
- Tables
o All tables need information on analysis and abbreviations used in the table as a footnote. Table
3 also needs the definition of paths.
o Table 1: Should include BMI
o Table 2: Genera should be italicized.
- Table 2 and the results section regarding it could be its own section, rather than in the participant
demographics. These are analyses that were conducted and could stand alone.
- Lines 298-301: This analysis and description should be in the statistical analysis section in
the methods.
Discussion:
- Line 327: citations for cardiometabolic risk and disorders, and plant intake related to abundance
of Blatuia and Faecalibacterium.
- Lines 355-355: Hard to follow, please reword.
- Paragraph starting at 360, it is also important to consider that Akkermansia is increased in
Parkinson’s disease.
o Alistipes and vegetable ending sentence does not seem to fit in the rest of the paragraph.
- Line 378: Inflammatory score could be its own paragraph.
- Line 390: “increased Alistipes”,  Table 1 and line 252 does not support this finding. Please
clarify.
- Line 402: need an ending sentence to bring inflammation and barrier integrity back to your
findings.
- Line 412: How were they determined to be metabolically healthy? Inclusion is from a BMI of
18.5 and 45 kg/m2. There is no description of how this was defined.
o BMI may also be a mediating factor and should be considered in analyses.
Conclusion:
- The conclusion should be shortened to one paragraph of the main findings. The second
paragraph would fit better into the discussion.