Personal traits, lifestyle decisions, and geography shape our dietary intake and consequently our bacterial and fungal gut microbiome

Background The Global Burden of Disease 2017 (GBD-2017) study identified high sodium intake, low whole grain intake, and low fruit consumption as key dietary risk factors for non-communicable diseases (NCDs). We hypothesize that individual characteristics and lifestyle factors influence these dietary risks, thereby modulating the composition of the gut bacterial and fungal communities. Results From 2020 to 2024, we enrolled 1001 participants from four Spanish regions. Participants completed a short Food Frequency Questionnaire (sFFQ) at baseline, month six, and month 12 (n = 2475). Age, gender, geography, and seasonal factors significantly shaped dietary patterns, with older age and healthier diets, especially those rich in fruits and vegetables, linked to increased gut microbiome diversity. Participants generally consumed less legumes, whole grains, and nuts but exceeded recommended red meat and sugar intake levels, with men showing poorer dietary habits and faster gut transit times correlating with distinct microbiome profiles and lower diversity. Using machine learning techniques, dietary intake can be predicted by the gut microbiome composition. Participants can learn about the study, their diet and their microbiome here (https://manichanh.vhir.org/POP/;username:reviewers;password:reviewers) Conclusion Adherence to national dietary guidelines, particularly the Mediterranean diet, enhances gut microbial diversity. Personal, lifestyle, and geographic factors significantly influence dietary quality, highlighting the need for targeted interventions. The study suggests that improving dietary patterns positively impacts the gut microbiome and overall health in Spain.