Académie royale de Médecine de Belgique

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Résumé de Sara Vieira-Silva

THE FLEMISH GUT FLORA PROJECT : THE POWER of metagenomics for population-level studies  

par Sara VIEIRA-SILVA (Department of Microbiology and Immunology - KULeuven), invitée.  

The Flemish Gut Flora Project (FGFP) represents one of the largest population-wide studies monitoring the gut microbiota of healthy volunteers. Initiated in 2012, the project tackles the ambitious task of mapping gut microbiome compositional variation, using metagenomics, in the population of Flanders (Belgium). The aim of this endeavour is to investigate links between the human gut microbiota and health or disease, diet, and lifestyle.

Through the analysis of more than 3,000 human faecal samples, the FGFP team has identified 69 factors co-varying with gut microbiota composition. Most of these microbiome covariates are related to transit time, health, diet, medication, gender, and age. Stool consistency, a proxy for intestinal transit time, was identified as the single factor associated with the largest variation in microbiota composition. However, also diet was shown to be an important covariate, with most associations related to fibre intake. Other associations incite deeper investigation, such as the relationship between the microbiota composition and hemoglobin concentrations or red blood cell counts, both reflecting blood oxygen uptake capacity. As expected, medication had a significant impact on gut microbiota variation. FGFP researchers not only identified associations with antibiotics, but also with hay fever treatment and hormones used for contraconception or alleviation of menopause symptoms. Remarkably, early life events such as birth mode or whether or not volunteers were breast-fed as infants were not reflected in adult microbiota composition.

Although this first cross-sectional FGFP analysis has enriched current knowledge on gut microbiota composition, it only allowed to associate 7% of gut flora variation to health, diet, and lifestyle. FGFP microbiome exploration efforts are still ongoing and recent innovations in the project’s analytical approaches promise additional insights in microbiota community structure and its relation with the human host.