How Different Are the Influences of Mediterranean and Japanese Diets on the Gut Microbiome?

The gut microbiome is a complex ecosystem, mainly composed of bacteria, that performs essential functions for the host. Its composition is determined by many factors; however, diet has emerged as a key regulator. Both the Mediterranean (MD) and Japanese (JD) diets have been associated with significant health benefits and are therefore considered healthy dietary patterns. Both are plant-based diets and although they have much in common, they also have important differences mainly related to total calorie intake and the consumption of specific foods and beverages. Thus, it has been hypothesized that they exert their beneficial properties through different nutrients and bioactive compounds that interact with gut microbes and induce specific changes on gut metabolic pathways. In this review, we present current data on the effects of the MD and JD on the gut microbiome. Furthermore, we aim to examine whether there are differences or shared effects on the gut microbiome of people who adhere to these dietary patterns.