Review Reports - Calcium from Finger Millet—A Systematic Review and Meta-Analysis on Calcium Retention, Bone Resorption, and In Vitro Bioavailability

Round 1

Reviewer 1 Report

The manuscript titled "Calcium from finger millet – A systematic review and meta-analysis on calcium retention, and in-vitro bioavailability" investigated to determine the retention and impact of finger millet calcium on bone calcium resorption. The study showed that the high levels of calcium in finger millet hold a promise for health benefits associated with finger millet integration into more diets and programs.

The ms fully falls within the editorial purposes of the journal and is focused on a very current issue, albeit extensively investigated in the literature. The ms is well structured and contains a large amount of very interesting and convincing data but an adequate review appears necessary before publication. I list some comments and suggestions for improvements below:

It is preferable one sentence to define the problem in “Abstract”.
The keywords must not be repeated in the title.
Line 89-95: The objective are not clear and need to be significantly improved.
‘Materials and Methods’ section: Further explanation should be given for meta-analysis.
The measurements, such as Newcastle-Ottawa Scale (NOS), used in the study lack explanation.
Delete the abbreviation "NOS", to not repeat it.
Table 5 should be move to ‘Results’ section.

Author Response

Reviewer 1

It is preferable one sentence to define the problem in “Abstract”.

Response: It is added now. Line 19

The keywords must not be repeated in the title.

Response: The keywords are changed now. Line 41-42

Line 89-95: The objective are not clear and need to be significantly improved.

Response: The objectives are improved now. Line 112-115.

‘Materials and Methods’ section: Further explanation should be given for meta-analysis.

Response: This section is now improved. Line 179-184.

The measurements, such as Newcastle-Ottawa Scale (NOS), used in the study lack explanation.

Response: This is now added in materials and also in results. Line 174-175, 316-317.

Delete the abbreviation "NOS", to not repeat it.

Response: As NOS is repeated now in results it is not deleted.

Table 5 should be move to ‘Results’ section.

Response: Thank you. It is not part of results. This table is used to enhance the discussion part therefore retained in discussion.

Reviewer 2 Report

Overall, the manuscript is well written, however the data analysis part requires to be improved as only 3 studies were finally considered and out of which 2 were almost 60 years old. The authors should have mentioned the time domain for inclusion of documents and screen the recent ones for inclusion and analysis.

Abstract: The authors should mention the methodological framework, how many research articles were considered, what was the criteria of inclusion and exclusion etc.

The authors should provide a conclusive statement about increase or decrease in bioavailability of calcium after processing.

What exactly authors want to depict about calcium retention?? it should be reflected in abstract.

Introduction: Line 51-54 please improve the description, as mentioning the side effects of calcium supplemental tablets would oppose commercially available calcium supplements which are approved for human use.

Provide the composition of finger millet its potential benefits, available traditional products and proven health benefits from literature.

Materials and methods: Please describe the criteria of inclusion and exclusion of studies in more detail. As 312 for screened and only 4 were selected to proceed, some detailed characterization should be mentioned.

The articles that were selected for meta analysis are almost 60 years old (2 out of 3), which may outdate the findings of this study. Therefore the time domain to select the articles should be highlighted in method section.

Results: The bioavailability of calcium should be discussed with details and possible variables influencing the bioavailability and calcium retention.

Conclusion section should be revised and should be in accordance with the solution to research question.

Author Response

Reviewer 2

Response: The time domain was not restricted to recent ones considering the scarcity of the study area based on our observation during scoping study. Considering the importance of the topic and need for research in this area the old articles were also included which is now mentioned in inclusion criteria and it is also recognised in limitation section. Line 148-149, 427-439.

Abstract: The authors should mention the methodological framework, how many research articles were considered, what was the criteria of inclusion and exclusion etc.

Response: Abstract has word limitation of 200. However, we tried to include the studies that was eligible and was not eligible and the reason.

The authors should provide a conclusive statement about increase or decrease in bioavailability of calcium after processing.

Response: This is added now in abstract. Line 37-39.

What exactly authors want to depict about calcium retention?? it should be reflected in abstract.

Response: This is added now in abstract. Line 30-31.

Response: It is based on already published information therefore we do not see the problem in providing this statement. Moreover, side effects are common for every single drugs. We corrected the word side effect to undesirable effect to make sound little bit less than side effect.

Provide the composition of finger millet its potential benefits, available traditional products and proven health benefits from literature.

Response: Thank you for this valuable point. It is added now. Line 77-84.

Response: Out of 312 studies 7 were selected, 3 were from human studies and 4 are in-vitro studies. Inclusion and exclusion criteria is revised now with some more information. In results it is also mentioned why 302 studies were excluded. 148-151, 155-158.

The articles that were selected for meta-analysis are almost 60 years old (2 out of 3), which may outdate the findings of this study. Therefore, the time domain to select the articles should be highlighted in method section.

Response: It is captured now in method and it is also recognised in limitation section. Line 148-149, 427-239.

Results: The bioavailability of calcium should be discussed with details and possible variables influencing the bioavailability and calcium retention.

Response: This is now added in discussion. Line 323-331.

Conclusion section should be revised and should be in accordance with the solution to research question.

Response: It is revised now. Line 464-469.

Reviewer 3 Report

This is a very interesting study on the usefulness of finger millet as a dietary source of calcium.
In the introduction it would be interesting to add the caloric intake of the product. The majority of consumers of calcium-fortified products are obese menopausal women and caloric intake is a very limiting factor.
In material and methods I would add supplementary material for a detailed description of the search strategy used.
Regarding results:
1-Figure 1 shows the flow of articles for the first meta-analysis in humans but the flow of in-vitro studies would be missing
2-A meta-analysis of two studies is of little use. '
3-In figure 2 indicate the meaning of the acronyms.
In summary, the article is interesting to read but provides little scientific evidence due to lack of studies.

Author Response

Reviewer 3

Thank you for your valuable comment. The composition and health benefit of consuming finger millet such as managing diabetes, lipid profile, obesity and hypertension is added in introduction. Line 77-84.

In material and methods I would add supplementary material for a detailed description of the search strategy used.

Response: The details of the search strategy have been enhanced in the paper and so you don’t think supplementary material is needed.

Regarding results:

1-Figure 1 shows the flow of articles for the first meta-analysis in humans but the flow of in-vitro studies would be missing

Response: Thanks for noticing this. It is included in flow diagram now. Figure 1.

2-A meta-analysis of two studies is of little use. '

Response: It is recognised in limitation section. Line 427-239.

3-In figure 2 indicate the meaning of the acronyms.

Response: Abbreviations are added now in Figure 2.

In summary, the article is interesting to read but provides little scientific evidence due to lack of studies.

Response: This is recognised in limitation and also recommended for future research highlighting the importance of having this information.

Round 2

Reviewer 2 Report

The manuscript has been revised as advised by the reviewers, therefore the manuscript can be considered for publication

Reviewer 3 Report

I consider that the article is ready for publication after the corrections made