PONE-D-20-39099

Contribution of processed foods to salt intake and iodine intake of Sri Lankan population and the potential impact of salt reduction on iodine intake

PLOS ONE

Dear Dr. Jayatissa,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

• The authors limited the analysis to only three industrially processed foods (bread, dried fish and biscuits). Other products like canned fish, margarine, cheese and butter were excluded based on the assumption that they were not frequently consumed. Further other important sources of dietary salt including tomato ketchup has not been mentioned. I recommend the authors to do sensitivity analysis on this decision of excluding these foods from the analysis.
• The study estimated average daily Individual consumption of salt and industrially processed food by dividing food available at household level by number of household members. The estimation seems erroneous because it assumed that all household members consumed equal amount of food. I recommend the authors to take the age and sex profiles of the household members into consideration and recalculate adult-equivalent level of consumption for the households.
• How did the authors combined district level consumption data and estimate daily per capita consumption for each province? Assuming the population size of the districts is different, weighted analysis should be applied.

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Samson Gebremedhin, PhD

Academic Editor

PLOS ONE

Additional Editor Comments (section-by-section comments):

Introduction

Is there any empirical evidence that there is shifting towards increased consumption of IPF in Sri Lanka? In the introduction section, can you please present numeric figures supporting this shift?

Methods

Line 100-1: “The survey also collected information on the quantity of salt purchased at household level monthly”. What if salt is not purchased in that schedule? How did you handle such scenario?

Line 133: “The average percent salt content of dried fish from the laboratory analysis was 16%.” Have you tried to validate this lab finding with existing literature?

Results

Line 157-61: Rather than taking the highest estimate of 8.5mg, why it was not possible to take mean of means?

Discussion

Please discuss the implication of assuming equal intake of dried fish and biscuits across all the provinces.

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Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Partly

Reviewer #2: Yes

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2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: No

Reviewer #2: Yes

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3. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: No

Reviewer #2: Yes

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Reviewer #1: Yes

Reviewer #2: Yes

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5. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: The manuscript entitled “Contribution of processed foods to salt intake and iodine intake of Sri Lankan population and the potential impact of salt reduction on iodine intake” (PONE-D-20-39099) had been reviewed and the comments are listed below.

Presented manuscript is interesting and the estimation of the contribution of industrially processed food to salt and iodine intake is now a frequent topic of debate among nutritionists and the food industry. Nevertheless to clear up all given information, major supplementations need to be done. Consequently the authors are asked to respond to these comments.

Manuscript’s title should be corrected as it does not fully reflect to the content since the intake of salt and iodine was estimated on a very narrow group of products.

The term of industrially processed food should be defined. The Authors included dried fish, bread and biscuits. Could it be named a industrially processed food? Reading the paper one has a feeling that the meaning would be to reduce the salt consumption on ultra-processed food, but actually there is no clear information weather foods selected for estimation were of industrial or homemade. When analyzing the iodized salt intake it should not be forgotten, that iodine components are susceptible to numerous changes e.g. sunlight, oxygen, temperature, presence of other food components, which eventually can significantly deplete the iodine content in the product. There are no information about the potential changes during food preparation and processing conditions, as well as iodized salt storage time. All those factors significantly influence the iodine intake.

It is not claer what is the average consumption of the analysed food. Used for the research HIES quantitative data are from 2016, the Department of Census and Statistics decided to conduct the HIES once in every three years in Sri Lanka, which shows the data may not be up to date. Is that the most consumed food by all consumers, so its salt and iodine content would whether represent the surveyed group of consumers, or is it consumed occasionally, also due to the changing nutritional trends of Sri Lanka citizens? Needs clarification.

The Material and method section is too long and not informative, the modelling process used for the paper preparation is not clear. The section needs ordering.

Analysis of the material in the publication indicates that the study may not be representative of salt and iodine intake as it only covers 3 groups of products: bread, biscuits and dried fish. The authors presented the limitations of their research (line 279-291), but their importance may indicate too many significant ambiguities and shortcomings of the analysis performed.

The Authors did not include a statistic analysis information and how the modelling process was conducted. If the results are estimated as described in the tables it is not sufficient for a scientific paper and needs to be supplemented.

Above mentioned comments confirm need of careful corrections and supplementations to obtain proper scientific load. Therefore, I do not recommend it in its current form for further steps of PLOS ONE publication process. My recommendation is major revision, since, as described above, the work requires proper suplementation.

Reviewer #2: It should be better specified whether potential iodine intake from household salt and IPF salt sources was calculated assuming that salt was iodized to 15 mg/kg or 30 mg/kg or to the mean value of 21 mg/kg cited at line 56. In Fig.1 it is reported that estimated current iodine intake is based on 78% of household salt being iodized to at least 15 mg/kg, but in the Method section a range of 15-30 mg/kg is indicated (line 143). This point should be clarified.

In the abstract and through the text the expression "Industrially Processed Foods" is abbreviated as IPF and IPFs. Please use one of them.

At lines 146-147 the Authors state “.....78% of housholds were using iodized salt with some amount

of iodine while 78% of households use salt with at least 15 mg/kg iodine”. The first percentage is probably higher than 78%. Is it 95% as stated at line 54?

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Reviewer #1: No

Reviewer #2: No

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Estimated contribution of most commonly consumed industrialized processed foods to salt and iodine intakes in Sri Lanka

PONE-D-20-39099R1

Dear Dr. Jayatissa,

We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements.

Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication.

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Kind regards,

Samson Gebremedhin, PhD

Academic Editor

PLOS ONE

Additional Editor Comments (optional):

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #1: All comments have been addressed

Reviewer #2: All comments have been addressed

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2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

Reviewer #2: (No Response)

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3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: N/A

Reviewer #2: (No Response)

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4. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #2: (No Response)

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5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #2: (No Response)

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6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: Considering the submitted revision of the manuscript, the replies given and the changes made by the authors corresponding to each concern raised by the reviewer are satisfactory and convincing, therefore the quality of the manuscript has improved significantly. For these reasons I recommend acceptance of the work in its present form and publication in PLOS ONE journal.

Reviewer #2: (No Response)

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7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

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Reviewer #1: No

Reviewer #2: No