Vitamin D Food Fortification Strategies on Population-Based Dietary Intake Data Using Mixed-Integer Programming
Round 1
Reviewer 1 Report (Previous Reviewer 3)
The authors have adequately addressed all the comments.
Reviewer 2 Report (Previous Reviewer 1)
The work has been corrected, although not all of the reviewer's comments have been considered. Therefore, I am asking the editor to decide whether to publish the article.
Literature can certainly be updated.
The authors also state that "this paper explores the possibility of vitamin D fortification on the current population food intake in Denmark, such that the population gets adequate amount of vitamin D without having to change the current dietary patterns".
Are your current eating patterns correct? Authors should take this into account.
The article requires correction of the English language.
This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.
Round 1
Reviewer 1 Report
The work "Vitamin D food fortification strategies on population based dietary intake data using mixed integer programming" is interesting; however, it needs to be corrected.
Lines: 44-45 Please add references
Lines 46-52. The authors discuss the results for Finland, Sweden and Norway, Northern European countries. Please explain why for these countries only, justify your choice.
Lines 51-52. The authors report: "Butter, margarine and some low-fat milk products are fortified voluntarily in Norway, but at lower doses than in Sweden and Finland." Please explain, and compare the contents.
The Introduction section should be enriched with an explanation of the effects of vitamin D deficiency.
Materials and Methods
Regardless of the table number, all abbreviations used in the tables must be explained below the table.
Please describe, and explain the concepts contained in table 1:
Average requirement (AR); Recommended intake (RI); Tolerable upper level (UL)
In the title of Table 1, add that it concerns the Danish population.
Table 1. Is there no division into girls and boys, women and men?
Table 1. What does 04-10 (Age range) mean? The same in the line 185, table 6.
Line 152-154. Is this a statistical calculation program? What statistical measure will determine the level of the model?
Please describe the models in detail; they are hardly legible in their current form.
An explanation of each model should be found under Tables 3 and 4.
It would be beneficial to list the limitations of this work.
Due to doubts regarding the research methodology, it isn't easy to refer to the results presented in the Results and Discussion section.
Reviewer 2 Report
The article presents quite interesting study concerning the use of specific programming to find the best strategy to increase dietary intake of vitamin D in the population. In my opinion, the study has been correctly planned, performed and described. However, English should be corrected by a professional, because now it is not too easy to follow the authors' ideas.
Reviewer 3 Report
The article describes the development of a strategy for food fortification for the Danish population with the use of mixed integer programming. The use of a computational model produced a strategy for fortification of specific food groups that results in minimum intake of average requirement for the majority of the population while the upper limit is not exceeded.
The introduction is adequate, the article is methodologically sound and the results are clearly presented and adequately discussed.
Overall this is an interesting computational approach for the development of a fortification strategy for vitamin D. It is expected that the article can be potentially useful for development of fortification policies and of interest to the Journal readers.
Comments and recommendations to the authors:
2.1. Major comments:
1. It is well known that vitamin D levels (25OHD serum levels) have a seasonal variation. There is no calculation or correction of the model for this. The authors are encouraged to discuss possible differences between winter and summer in the outcomes of their model.
2. Vitamins D2 and D3 do not have the same potency for increasing 25OHD levels but this fact either is not included in the calculation or there is an assumption that D3 is used always. Although in the majority of foods D3 is used, the difference should be discussed.
2.2. Minor comments:
3. Table 1: The authors need to add a reference citing the source for the AR, RI and UL that they are using.
4. Table 3: The authors need to add a reference citing the source of the vitamin D content of foods that they are using.
5. Figures 1 and 2: The authors need to include the units of the x axis (e.g. Vitamin D intake (μg/day)) in the legend and preferably also in the figure.
The sample size needs to be mentioned in the legend and/or the figures in order for the figures to be easier understood by the reader.
Additionally, in the version provided for review, in figure 2 (a) and (b) the y axis legend is only partially visible.
