Can the FUT 2 Gene Variant Have an Effect on the Body Weight of Patients Undergoing Bariatric Surgery?—Preliminary, Exploratory Study

Background: The FUT2 gene (Se gene) encoding the enzyme α-1,2-L-fucosyltransferase 2 seems to have a significant effect on the number and type of bacteria colonizing the intestines. Methods: In a group of 19 patients after bariatric surgery, the polymorphism (rs601338) of FUT2 gene was analyzed in combination with body mass reduction, intestinal microbiome (16S RNA sequencing), and short chain fatty acids (SCFA) measurements in stools. Results: Among the secretors (Se/Se polymorphism of the FUT2 gene rs601338, carriers of GG variant), correlations between waist-hip ratio (WHR) and propionate content and an increase in Prevotella, Escherichia, Shigella, and Bacteroides were observed. On the other hand—in non-secretors (carriers of GA and AA variants)—higher abundance of Enterobacteriaceae, Ruminococcaceae, Enterobacteriaceae, Clostridiales was recorded. Conclusions: The increased concentrations of propionate observed among the GG variants of FUT 2 may be used as an additional source of energy for the patient and may have a higher risk of increasing the WHR than carriers of the other variants (GA and AA).