The small bowel microbiome changes significantly with age and aspects of the ageing processOriginal paper
Karen Pendergrass is a microbiome researcher specializing in microbiome-targeted interventions (MBTIs). She systematically analyzes scientific literature to identify microbial patterns, develop hypotheses, and validate interventions. As the founder of the Microbiome Signatures Database, she bridges microbiome research with clinical practice. In 2012, based on her own investigative research, she became the first documented case of FMT for Celiac Disease, four years before the first published case study.
Read MoreWhat was studied?
This work examined how age and the ageing process reshape the small intestinal microbiome, which prior stool studies could not capture. Researchers sampled the duodenum directly. Duodenal aspirates were collected during upper endoscopy using validated techniques that limit saliva and stomach contamination. Samples came from the REIMAGINE study. The team separated three overlapping influences. They defined the ageing process as chronologic age, number of concomitant diseases, and number of medications, then tested each effect on duodenal taxa and on metabolic and inflammatory markers.
Who was studied?
The cohort was 251 adults aged 18 to 80 years who underwent standard-of-care upper endoscopy without colon preparation. All provided duodenal aspirate samples plus medical history. Subjects were split into four age groups: 18 to 35, 36 to 50, 51 to 65, and 66 to 80 years. This was a human clinical cohort, not an animal or in-vitro model. Blood biomarkers were also measured, letting the team link duodenal microbes to fasting glucose, TNF-alpha, and IL-8 across the age range.
What were the most important findings?
Duodenal microbial diversity fell significantly in older subjects. Multivariate analysis showed the decline was driven by the whole ageing process, not chronologic age alone. Proteobacteria rose from the 5th to the 2nd most prevalent phylum, driven by family Enterobacteriaceae and coliform genera. Bacteroidetes fell from 3rd to 5th most prevalent. Culture confirmed rising live coliform counts. Seven genera tracked chronologic age alone, four of them anaerobes. One coliform disruptor rose solely with medication count. Fasting glucose and TNF-alpha rose with the ageing process.
What are the greatest implications of this study?
The small bowel microbiome changes progressively with age, and stool samples miss these shifts. The duodenum shows its own age signature dominated by coliform expansion. Because certain taxa tracked medication count or disease burden rather than age itself, chronologic age alone poorly predicts an individual's duodenal ecology. The rise in coliforms and anaerobes, plus predicted ubiquinone pathway changes, may relate to age-linked metabolic and inflammatory shifts. These associations are observational and do not establish that microbes cause the changes.