Created on 05 June 2013

Diet  is  a  reservoir  of  microbes  and  the  feeding  for  human  resident microorganisms, therefore, it is inevitably linked to diversity and functionality of the oral and intestinal  microbiota.  The  oral  and, especially, the intestinal microbiota are valuable “traits d'union”/determinants between diet and human well being. As succinctly stated  in  the  document  Horizon  2020  (page  56),  “a  better  understanding of the determinants of health is required in order to provide evidence for effective health promotion  and  disease  prevention.  Approaches  will  include  the  long-term  study  of cohorts and their linkage with data derived from "-omics" research, and other methods”.  Excluding obvious geographical differences, three main dietary habits are worldwide diffused: omnivore, vegetarian and vegan. A cross-search for "human gut  microbiota"  and  "health"  in the ISI Web of Knowledge database, results in more than 550 hits, only in the last 5 years. Less than 10 hits come out combining the terms “vegetarians” and "human gut microbiota".

Based  on the above considerations, the overall objective of this project is to estimate the intake of microorganisms based on the omnivore, vegetarian and vegan diets, and to find the relationship between diet and saliva and fecal microbiota, through high-throughput and integrated meta-omics (genomic, transcriptomic, proteomic and metabolomic)  analyses.  Several  questions  are  still  debated within this context. For instance, what is the daily intake of microbes and their role on the balance of the intestinal microbiota? How is the intestinal microbiota affected by the main types of diet (omnivore, vegetarian and vegan)? Which are the prevailing microbial groups at  intestinal  level, depending  on  the type of diet? What is the presumptive contribution of each microbial group in maintaining the host health? The quantitative and qualitative  determination  of  the main microbial groups harboured in foods, depending on dietary habits, responds to an earlier question and coincides with one of the objectives  of  this  project.  The  estimation  of  the  diversity  (genomics),  functional  activity  (transcriptomics  and  proteomics)  and metabolites (metabolomics) of, especially,  the  fecal  microbiota  coincide  with  the holistic approach of this project and responds to several of the earlier questions. Considering the close correlation between  the  balance  of  different  microbial  populations  in various niches of the human body and the onset of metabolic pathologies, this project shall furnish novel knowledge  that  may  highlight  possible relationships between diet and dismetabolisms. The results of this project will have the objective to manage the diet in a way
that  permits  the modulation of microbial populations and favours those responsible for the synthesis of beneficial compounds and for pathogen inhibition. Diet has to be considered as the most appropriate and inexpensive tool to determine a stable and favourable oral and intestinal microbiota, which prevents diseases and guarantees human  longevity.  These  overall  objectives  of  the  project shall be reached on the basis of specific targets, such as: (i) the identification of biological, molecular and metabolic  markers specific to the type of diet; (ii) the estimation of the differences in the microbiota and metabolome of saliva and feces, both among individuals and between types of diet; (iii) the estimation of the qualitative and quantitative differences on the microbial intake connected to the type of diet; and (iv) the identification of the functional features of fecal samples related to the type of diet, which can be regarded as indicators of disease susceptibility.

Given  the large number of Research Units involved in this project as well as the numerous International partners willing to collaborate, an equally important objective is to establish a permanent National and International platform for this and future projects.