Comparative Assessment of Nutraceuticals for Supporting Skin Health

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

General Comments:

The review of Nutraceuticals for Supporting Skin Health was both interesting and thorough. I appreciated the fairly well-balanced approach and the focus on level of evidence. Why was a systematic review not considered? What type of review do the authors classify this work as? I apricated the organization of the substances into categories and did not have suggestions for additional inclusions. There was one significant omission to the review. This was not including what is known about the digestion and absorption for of each of the nutraceuticals in question.

 

Major Comments:

There is need a “Digestion and Absorption” section for each of the nutraceuticals. Without this detailed for each substance the mechanism and link between dietary intake of the nutraceutical and observation is limited.  When including this section for each substance in a revision, be systemic following: a) how is it consumed, b) how is broken-down (digested), c) how is it transported across the apical and basolateral membranes of enterocytes, d) where in the GI track is it digested and absorbed, e) is it transported by the portal vein or lymphatics, and f) is there a probably “first pass” effect in the liver. I am not worried if some of the digestion and absorption is unknown or some speculation is necessary but this it will allow the reader to know what is known this integral aspect. Without this information the contents are severely limited.

Skin health can be hard to define. Many studies will also define it differently. Please provide a table or bulleted list in the “Skin Health” of the outcome variables that you specially evaluated in this literature-based review.

 

Minor Comments:

How many studies in a certain area or type are needed for the classification system from the German Society for Dermopharmacy?

Dose of the nutraceutical is hard to factor into the evidence. How was this handled? Especially is one dose resulted in an observable effect and another did not.

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The article is interesting as it highlights the role of nutraceuticals on the skin. However, a number of considerations are made:
1.- The introduction is a little long, perhaps it should be summarised and focused on the subject of the article. 
2.- The objective or objectives of the work should be made more specific.
3.- The procedure followed for the selection of the articles in tables 3, 4, 5 and 6 should be described in more detail. 
4.- There is an excessive volume of articles used in the tables; perhaps it would be necessary to indicate those that have a specific purpose in relation to the role of the skin. 
5.- There is a large number of articles for a very short discussion. 
6.- A section on conclusions is missing.

 

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

It is a very interesting manuscript. There is an almost comprehensive review of both potent actives and dietary supplements used as neutraceuticals. The illustration of results is very explanatory and all tables have been written very sufficienltly. The references although, are too many are very focused and give all the history and last update for neutraceuticals.

I would propose to separate the plant, fish collagen from bovine and porcine one, cause of regulatory issues. You have to refer that bovine and porcine collagen contained in food supplements have the main advantage that are permited in them but prohibited in cosmetics due to BOV and so they may be used as neutraceuticals and have the benefits in skin care.

I sould advice you to expand the discussion and diminish the results, since a lot of interpretations are refered there.

 

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The revised version did not raise additional comments or concerns.

Author Response

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Author Response File: Author Response.docx