Quantitative GC-TCD Measurements of Major Flatus Components: A Preliminary Analysis of the Diet Effect.

Rafael Freire,Silvia Mas,Santiago Marco,Antonio Pardo,Marianela Mego,Luciana Fontes Oliveira,Fernando Azpiroz

doi:10.3390/s22030838

Abstract

The impact of diet and digestive disorders in flatus composition remains largely unexplored. This is partially due to the lack of standardized sampling collection methods, and the easy atmospheric contamination. This paper describes a method to quantitatively determine the major gases in flatus and their application in a nutritional intervention. We describe how to direct sample flatus into Tedlar bags, and simultaneous analysis by gas chromatography–thermal conductivity detection (GC–TCD). Results are analyzed by univariate hypothesis testing and by multilevel principal component analysis. The reported methodology allows simultaneous determination of the five major gases with root mean measurement errors of 0.8% for oxygen (O2), 0.9% for nitrogen (N2), 0.14% for carbon dioxide (CO2), 0.11% for methane (CH4), and 0.26% for hydrogen (H2). The atmospheric contamination was limited to 0.86 (95% CI: [0.7–1.0])% for oxygen and 3.4 (95% CI: [1.4–5.3])% for nitrogen. As an illustration, the method has been successfully applied to measure the response to a nutritional intervention in a reduced crossover study in healthy subjects.

Highlights

The volume, production, and elimination of intestinal gas are well understood, and it is known that the composition of the gas evacuated per anus reflects the metabolic activity of intestinal microbiota [1,2,3]
On the one hand, determining a standard healthy pattern of intestinal gas is challenging due to the large differences in the volume and composition of intestinal gases between individuals [8,9,10]. These differences are attributed to the nature of human gut microbiota, which is responsible for much of the production of intestinal gas
This study presents a procedure for direct rectal gas collection with preventions for atmospheric contamination, quantitative analysis by gas chromatography–thermal conductivity detection (GC–TCD), and a multivariate data processing method for the analysis of the five major gas components

Summary

Introduction

The volume, production, and elimination of intestinal gas are well understood, and it is known that the composition of the gas evacuated per anus reflects the metabolic activity of intestinal microbiota [1,2,3]. On the one hand, determining a standard healthy pattern of intestinal gas is challenging due to the large differences in the volume and composition of intestinal gases between individuals [8,9,10]. These differences are attributed to the nature of human gut microbiota, which is responsible for much of the production of intestinal gas. It is known that many hundreds of different bacterial species can be found in the colon and they contain 100 times more genes than their human host [11,12,13], and within individuals, it is known that a particular microbiota depends on the colonization history of each individual and it is sensitive to a multiplicity of factors as environment, age, diet, lifestyle, climatic conditions, blood group, diseases, or exposure to antibiotics, among others [11,13,14,15]

Methods

Discussion

Conclusion