Functional Food as a Nutritional Countermeasure to Health Risks from Microgravity and Space Radiation in Long-Term Spaceflights: A Review

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This paper provides a comprehensive overview of the role of functional foods as a key solution to the health problems faced by astronauts during long-duration space missions. The study was conducted using a literature review method, using databases such as Scopus, FSTA and ScienceDirect.
The paper describes in detail the numerous physiological and biochemical changes that occur due to microgravity and space radiation. These changes include musculoskeletal decompensation (loss of bone and muscle mass), cardiovascular problems (such as decompensation and atrophy of the heart muscle), gastrointestinal health disorders (alterations of the gut microbiome and increased intestinal permeability), eye problems (such as cataracts, SANS and dry eye syndrome), alterations in the immune system, hormonal imbalances and oxidative stress.
The fundamental role of functional foods and dietary supplements as countermeasures against these problems is emphasized. The role of foods rich in flavonoids, omega-3 fatty acids, vitamins, minerals, antioxidant compounds, proteins, probiotics and prebiotics in strengthening the immune system, reducing bone density loss, muscle atrophy and oxidative stress is particularly highlighted. The paper also mentions the convenience and effectiveness of supplements in tablet form due to their stability, cost-effectiveness and ease of administration.
The paper looks at important innovations and technologies that can revolutionize nutrition in space. These include 3D food printing, algae cultivation in space and new preservation technologies, such as Pressure Assisted Thermal Sterilization (PATS) and Microwave Assisted Thermal Sterilization (MATS). Special emphasis is placed on the development of personalized nutrition tailored to the individual needs of astronauts.
Overall, the paper is very informative and relevant, providing deep insight into the complex health challenges of space missions and presenting functional foods as a key solution. It is particularly valuable that it not only describes the problems and solutions, but also clearly defines areas for future research and innovation, thus contributing to the guidelines for the further development of food systems for astronauts.

However, some minor refinements are needed:
- the number of subheadings in line 503 is not consistent with the main heading before it (the same with subheadings 4.2-4.4)
- to address the limitations of the research itself
- figure 3 - was there no overlap of the same works in different databases? If so - then this should definitely be stated, as well as the key queries used to search the databases.

Sincerely

Author Response

Thank you very much for your review of our manuscript. We've attached a PDF with our responses to your suggestions.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The manuscript focuses on the potential of functional foods in addressing health problems caused by microgravity and space radiation, highlighting their role in reducing oxidative stress and preventing bone mass loss, muscle atrophy, and other physiological imbalances. The authors emphasize the need for developing innovative preservation, packaging, and production technologies (such as 3D food printing and algae cultivation) to ensure the safety and effectiveness of these products during long-term space missions.

I appreciate that the paper is well-written, clearly presenting the health issues associated with spaceflights and subsequently highlighting the role of functional foods in counteracting them.

My observations are as follows:

• Given the relative scope of Chapters 3 and 4, I recommend revising the title to better reflect the manuscript’s focus.
• Since there are other similar literature reviews, the originality of this manuscript should be made more evident.
• Chapter 4 could be strengthened by including quantitative data, such as nutrient losses, limitations of current studies, and possible future research directions. If relevant articles are available, it would be interesting to compare bioavailability in space versus on Earth, as well as the stability of microorganisms in space.
• Chapter 5 – the link between algae or the presented technologies and the pathologies occurring in space should be explained more clearly. It would also be useful to compare these technologies with one another and specify their effect on bioactive compounds.
• Attention should be paid to the numbering of subchapters.

Author Response

Thank you very much for your review of our manuscript. We've attached a PDF with our responses to your suggestions.

Author Response File: Author Response.pdf