Impact of Plant-Based Meat Alternatives on the Gut Microbiota of Consumers: A Real-World Study

Round 1

Reviewer 1 Report

In this study, the authors compared these changes to those experienced by participants randomly allocated to a size-matched control group. Before and after stool samples from all participants were analysed using 16S rRNA sequencing

The authors observed small, but statistically significant changes in the presence of butyrate producing pathways, chiefly the 4-aminobutyrate/succinate and glutarate pathways in the intervention group, along with a consistent increase in the joint abundances of butyrate producing taxa. No such changes were observed in the control  group.

Alpha-diversity decreased marginally in the intervention group, whilst it increased in the control group. Beta-diversity between paired samples was higher in the intervention group but couldn’t be associated to number of PBMA meals consumed per week, although it may have been an indirect consequence of the increased amount of fibre and phenolic compounds provided by the PBMA, regardless of the frequency of the substitution.

We also observed a decrease in the Tenericutes phylum in the intervention group. A decrease in Tenericutes mediated by a dietary intervention has been documented as part of changes to the microbial community structure triggered by plant-based compounds, on the basis of which we also cautiously interpret this as a positive outcome.

To our knowledge, This study is the first randomised controlled trial to assess the mpact of commercially available PBMAs on the gut microbiome of participants in the United Kingdom.

We can confirm that the PBMA products provided to participants in the intervention group elicited changes to their gut microbiota that are consistent with eubiosis, i.e., “a healthy gut microbiome”, meaning that the replacement of animal meats with PBMA products seen in flexitarian dietary patterns may promote positive changes to the gut microbiome of consumers.

We acknowledge that the sample size was also relatively small, and that some of our key findings, e.g., improved butyrate metabolism potential, relied on biostatistical analyses that would need to be confirmed in a follow-up study with a larger sample.

Comments for author File: Comments.docx

Author Response

Dear Reviewer,

We would like to thank you for your detailed comments on our manuscript, which we have found very helpful. We have gone through all your suggestions and have taken them into consideration, editing the revised manuscript accordingly. 

Thank you once more for taking the time to review our manuscript. 

All the best,

Miguel Toribio-Mateas, Adri Bester, and Natalia Klimenko. 

Author Response File: Author Response.docx

Reviewer 2 Report

Major issues:

As demand for plant-based foods is increasing, the assessment of consumption of these products in our daily life becomes vital and essential. This interesting study was designed to investigate the effect of plant-based meat alternatives (PBMAs) on our health, particularly in gut microbiome. By the use of 16s rRNA sequencing, changes of butyrate metabolizing potential, as well as butyrate-producing taxa, were observed after 4 weeks diet intervention of PBMAs. However, some concerns needed to be addressing.

1. In order to evaluate the impact of PBMAs on gut microbiota, the authors focused on changes of butyrate producing potential. How about other taxa? Or, only taxa related to butyrate producing was significantly changed?
2. Have the authors looked into the end-products/metabolites related to butyrate metabolism in stool from participants with a consumption of PBMAs to confirm the microbial findings they found?
3. In Figure 5, the changes of microbiome in control before and after intervention were also observed, how do the authors explain these changes?

Minor issues:

4. By the statistical analysis, microbiota difference of within-group and between-group were explored. But the description of such microbiota changes was confusing. The significant changes from within-group and between-group should be marked in the figures as shown.

Author Response

Dear Reviewer,

Thank you so much for your detailed feedback. Please find our responses to the points you raise in the attached Word document with tracked changes.

We hope that you find our responses satisfactory and remain at your disposal for any further clarifications.

All best wishes,

Miguel Toribio-Mateas, Adri Bester, and Natalia Klimenko

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

All my concerns were reasonably replied by the authors, I have no further questions.

Author Response

Dear Reviewer,

Thank you so much for letting us know that your concerns were reasonably addressed and that you have no further questions. 

Best wishes,

Miguel Toribio-Mateas