[The influence of dietary pattern on the production of volatile organic compounds in patients with hydrogen-producing small intestinal bacterial overgrowth syndrome]

Abstract

Antibacterial therapy of the small intestine bacterial overgrowth (SIBO) is not effective enough and has a high relapse rate after treatment. Diet is a well-modifiable factor that plays a major role in shaping the composition, diversity, metabolic activity and stability of the intestinal microbiota. Intestinal bacteria ferment undigested food residues to form species-specific carbon-chain volatile organic compounds (VOCs). The aim of this research was to study possible correlations between dietary variables and the level of stool VOCs in patients with hydrogen-producing SIBO. Material and methods. The material of the study was the data of 100 patients referred for a hydrogen-methane breath test with lactulose in case of suspected presence of SIBO. Excessive bacterial growth of hydrogen-producing flora in the small intestine was determined by changes in the content of hydrogen and methane in exhaled air after consuming a portion of lactulose using the GastroCheck Gastrolyzer apparatus. The assessment of actual nutrition at home was carried out by 24-hour dietary recall. The determination of VOCs in patients' feces was carried out using gas chromatographymass spectrometry (a gas chromatograph equipped with a vapor-phase autosampler in combination with a triple quadrupole mass spectrometer). Results. Of the 100 patients examined, 41 were found to have a overgrowth of hydrogen- producing flora, 15 had an excess of methanogenic flora, and 10 had an excess of both hydrogen-producing and methanogenic flora. No signs of SIBO were found in 34 patients and they formed a control group. When comparing dietary parameters expressed in absolute values, significant differences were found only in relation to dietary fiber: patients with SIBO differed in a lower level of their consumption (19.8±9.1 vs 25.5±12.3 g/ day, p=0.023). At the same time, the index of healthy nutrition HEI-2020 in the control group was significantly higher (52.9±11.1 vs 44.4±14.4%, p=0.003). Due to the high variability of VOC levels, no significant differences between the groups for individual VOCs have been established. The results of the analysis of the structure of correlations between 84 variables of the nutrition assessment of the studied participants and 80 VOCs in their stool showed significant interdependence differences between patients of the studied groups. In patients with SIBO, the metabolic activity of the microbiota changed most significantly when eating leafy greens, berries, oatmeal and sausages, and in the control group when eating potatoes, tropical fruits, buckwheat and eggs. Conclusion. Thus, significant differences in the structure of correlations between dietary variables and the level of stool VOCs in patients with SIBO and the control group have been established.

Keywords: SIBO; chromatography-mass spectrometry; dietary assessment; microbiome; syndrome intestinal bacterial overgrowth; volatile organic compounds.