Comparative analysis of COVID-19 responses in Japan and Africa: diet, phytochemicals, vitamin D, and gut microbiota in reducing mortality—A systematic review and meta-analysis

Comparative analysis of COVID-19 responses in Japan and Africa, focusing on diet, phytochemicals, vitamin D, and gut microbiota in reducing mortality. Authors conducted a systematic review and meta-analysis to investigate the unexpectedly low COVID-19 mortality rates in Africa despite challenging health conditions. They found that a healthy diet rich in phytochemicals, particularly polyphenols and flavonoids, was effective against COVID-19. Blood vitamin D levels were associated with COVID-19 mortality, with Africa having higher average levels than many other regions. The gut microbiota was also linked to COVID-19 outcomes, with African populations showing a more diverse and healthier gut microbiome. Authors highlight the potential protective effects of these factors in Africa's lower COVID-19 mortality rates compared to developed countries. They note that the Japanese diet, similar to the Mediterranean diet, is associated with lower rates of underlying lifestyle-related diseases, potentially contributing to better COVID-19 outcomes. The review also examined the effects of vitamin D supplementation, finding statistically significant differences in vitamin D levels, hospitalization time, and cases. Authors suggest that maintaining adequate blood vitamin D levels and consuming phytochemicals are associated with a healthy gut microbiota and improved immune responses, correlating with lower COVID-19 mortality rates.

2 meta analyses show significant improvements with diet for hospitalization5, severity6, and cases5,6.