Human Gut Microbiota Profiles Related to Mediterranean and West African Diets and Association with Blastocystis Subtypes

<b>Background/Objectives</b>: The effects of geographical origin, alongside age, diet, and drug treatments, on the gut microbiota have not been thoroughly analyzed in African countries. Furthermore, eukaryotic components, including <i>Blastocystis</i>, the most common intestinal protozoan worldwide, require further investigation. This study compares the gut microbiota of Italian subjects with that of two African groups to examine the influence of dietary patterns and the effects of <i>Blastocystis</i> presence and subtypes. <b>Methods</b>: Three cohorts of healthy subjects (Italians residing in Rome, Africans residing in the Côte d'Ivoire, and Africans living in Italy) were compared by sequencing the V3-V4 hypervariable regions of the 16S rDNA gene. Taxa abundance and associations with typical West African and Italian foods were determined using DESeq2. Co-abundant genera were identified with a weighted correlation network analysis (WGCNA). <i>Blastocystis</i> subtypes were determined and correlated with the microbial composition in the three groups. <b>Results</b>: Distinct microbial taxa were associated with specific foods, including palm oil, Cube Maggi, sunflower oil, and olive oil. A Mediterranean diet consumed for over two years did not alter the abundance of <i>Faecalibacterium</i> and <i>Dorea</i> in the Africans living in Italy compared with Africans living in Côte d'Ivoire, whereas differences were observed in the abundance of some <i>Prevotella-</i>9, <i>Bacteroides</i>, and <i>Lachnospiraceae</i> OTUs. Significant associations were identified between palm oil and <i>Subdoligranulum</i>, Cube Maggi and <i>Dorea</i>, sunflower oil and the <i>Ruminococcus</i> torques group, and olive oil and <i>Faecalibacterium</i>. Concerning <i>Blastocystis</i>, alpha and beta diversity analysis showed a significant separation between carriers and non-carriers. <b>Conclusions</b>: This study provides the first comparative analysis of gut microbiota composition between individuals from Côte d'Ivoire and Italians focusing on the influence of distinct dietary patterns.