The preprint titled "Possible Roles of Phytochemicals with Bioactive Properties in the Prevention of and Recovery from COVID-19," authored by Sachiko Koyama and colleagues, investigates the potential benefits of phytochemicals in combating COVID-19. The study explores whether the consumption of vegetables rich in bioactive compounds is associated with reduced incidence and improved recovery rates of COVID-19. The review is marked by diverging opinions from its evaluators: one reviewer rated it as "Strong," noting the comprehensive approach despite raising significant concerns, while the other raised detailed criticisms about potential confounding factors and systematic biases that could affect the study's conclusions.

The review highlights that while the study provides valuable insights into the possible roles of phytochemicals, there are concerns regarding the design and analysis, including potential biases and confounding variables. The review reflects on the divided opinions, with one reviewer affirming the study's strength and another pointing out methodological issues. The critiques suggest areas for improvement in the research design to enhance the reliability and validity of the findings. For more details, readers are encouraged to consult the full review and the original preprint available through the provided links.