Human fecal 1H NMR metabolomics: Method development, metabolite library and first applications

Research output: Book/ReportPh.D. thesisResearch

  • Mengni Cui
In recent years, the number of older people is increasing rapidly around the world, therefore, improving their life quality and ability to be self-supportive is becoming very important.
Metabolomics of human plasma, urine and feces provided new insights into human health status and/or impact of diet or lifestyle. Human fecal metabolomics has a potential to uncover complex relationships between human metabolism and gut microbiome (GM). In this Ph.D. study, the fecal samples from 207 older adults (65-80 years old) and 40 young (18 years old) Danes were analyzed using three analytical platforms, proton nuclear magnetic resonance (1H NMR), gas chromatography-mass spectrometry (GC-MS) and near infrared spectroscopy (NIRS).
The thesis first describes the development of a standardized protocol for 1H NMR analysis of human fecal samples, by comparing 10 different protocols in fecal metabolomics. A new data processing method namely signature mapping (SigMa) has been employed to process fecal 1H NMR data for generating a quantitative metabolite table. The SigMa has proven to be an efficient and convenient method for rapid processing of complex spectra, and includes human fecal metabolite libraries that allowed absolute quantification of 36 fecal metabolites and relative quantification of more than 75 signals derived from unknown spin systems in fecal samples. Relationships between the confounding factors such as sex and age with the fecal metabolome have been found in this study.
These sex-dependent effects have been linked to the dietary food intakes, therefore, these effects on fecal metabolome are also expected to have correlations with functional foods that contain specific nutrients.
In addition, it has been shown that several diseases have strong effects on human fecal metabolic profiles, including obesity, diabetes, liver diseases and heart diseases that are influenced by ‘health risk factors’, such as body mass index (BMI), fitness, blood contents and blood lipoproteins (LP) level. Therefore, in this study, I investigated the effects of BMI/fitness and LP level on the human fecal metabolome and concluded that most of the significant metabolites are amino acids (AA) and short chain fatty acids (SCFA). Both AA and SCFA are very important metabolites for gut functions, it is expected that these findings will provide new insights into the preventions, detection and therapy of these diseases, as well as provide instructions to the older adults involved in the CALM
projects on how to eat and exercise for being self-supportive.
Original languageEnglish
PublisherDepartment of Food Science, Faculty of Science, University of Copenhagen
Number of pages226
Publication statusPublished - 2022

ID: 310500457