{
  "id": 9603364,
  "title": "Dietary fiber-type-specific gut microbiome preconditioning drives differential susceptibility to sporadic colon cancer development",
  "url": "https://urgent.news/2026/09/24/dietary-fiber-type-specific-gut-microbiome-preconditioning-drives",
  "topic": "health",
  "section": "Health & Medicine",
  "published": "2026-09-24T00:00:00.000Z",
  "source": {
    "name": "bioRxiv",
    "slug": "biorxiv",
    "url": "https://www.biorxiv.org/content/10.64898/2026.09.21.753221v1?rss=1"
  },
  "original_language": "en",
  "account": "Dietary fiber intake has been linked to a lower risk of developing colorectal cancer (CRC), but processed fiber supplements have shown mixed and sometimes contradictory effects on the development of colon tumors. Understanding how different types of dietary fibers impact the gut microbiome-metabolome axis in relation to cancer susceptibility has proven challenging. This study sought to investigate whether distinct dietary fibers have varying effects on colon tumor development and to identify the underlying mechanisms in the gut microbiome and metabolism.\n\nFour-week-old male mice were divided into four groups and given either a low-fiber control diet or a diet supplemented with cellulose, agar, pectin, or inulin for 28 weeks. All mice subsequently received eight intraperitoneal injections of azoxymethane (AOM), a carcinogen, at a dose of 7.5 mg/kg. Researchers analyzed the changes in the mice's fecal microbiomes using 16S-rRNA sequencing, measured the levels of cecal metabolites using H-NMR spectroscopy, and examined interactions between the microbiome and metabolome through co-occurrence networks.\n\nThe results revealed that supplementing the diet with inulin significantly increased the incidence of colon tumors (up to 70%) compared to the other groups, which saw tumor rates of 10-20%. The researchers then observed that the cecal extracts from mice fed with inulin promoted the growth of HT29 cancer cells. By conducting longitudinal microbiome profiling, they identified 36 inulin-specific microbial signatures that were shared across two major axes: a decrease in short-chain fatty acids (SCFAs) and the fermentation of cross-feeding taxa, as well as changes in amino acid and nitrogen metabolism.\n\nMetabolomics analysis corroborated these findings, showing an accumulation of succinate, fumarate, and lactate, along with a depletion of propionate and amino acids, specifically under AOM conditions. There were no differences observed in carcinogen-naive animals. Two stable co-occurrence hubs were identified exclusively in AOM-treated animals, integrating both functional axes in a tumor-promoting ecosystem.\n\nThe findings suggest that inulin supplementation alters the gut microbiome in a manner that makes it more vulnerable to cancer development. This vulnerability becomes pronounced when exposed to carcinogens, leading to a higher prevalence of tumors in inulin-fed animals. This study provides a mechanistic explanation for the disproportionate occurrence of colon tumors in animals that consume inulin-containing diets.",
  "summary": "Background: Dietary fiber intake is broadly associated with reduced colorectal cancer (CRC) risk, yet processed fiber supplements exert inconsistent and occasionally opposing effects on colon tumorigenesis. How structurally distinct dietary fibers differentially shape the gut microbiome-metabolome axis to influence carcinogenic susceptibility remains poorly understood. Objective: To determine…",
  "key_points": [],
  "editors_take": null,
  "illustration": null,
  "coverage": {
    "outlets": 1,
    "also_reported_by": []
  },
  "ai_generated": true,
  "disclaimer": "Summaries, key points and the editor’s take are written by software from other outlets’ reporting and may contain errors — always check the linked original."
}