The Japanese gut microbiome: ecology, uniqueness, and impact on health and disease

Metagenomics has become a powerful approach for deciphering the structure and function of the human gut microbiome, a complex microbial ecosystem in the gut. The human gut microbiome plays a crucial role in health and disease through multifaceted interactions with various factors, including age, diet, lifestyle, and medications. This review summarizes key advances in gut microbiome research over the past two decades and presents several topics from a recent large-scale, data-driven study, specifically a cohort-based initiative, the Japanese 4D microbiome project. These include a population-level characterization of the Japanese gut microbiome in a global context through comparison with 31,695 gut metagenomes from 37 countries, as well as an extensive analysis of the effects of medications. This review provides new insights into the ecology and uniqueness of the Japanese gut microbiome and highlights the importance of large-scale, well-phenotyped cohorts in advancing microbiome science.