Excessive Oral Intake of Vitamin B12 Alters Microbe-host Interactions That Stimulate Citrobacter Rodentium Growth and Virulence in Mice.
Bibliographic record
Abstract
Abstract Background: Vitamin B12 supplements typically contain doses that far exceed the recommended daily amount, and high exposures are generally considered safe. Competitive and syntrophic interactions for B12 exist between microbes on the gut. Yet, it has to be established to what extent excessive levels affect the gut microbiota and infection resistance. The objective of this study was to evaluate the effect of excess B12 on microbial ecology and pathogen virulence. Mice were fed a standard chow diet and received either water or water supplemented with B12 (cyanocobalamin; ~120 mg/day) and were subsequently challenged with Citrobacter rodentium, a mouse-specific pathogen. Infection severity was determined by body weight, pathogen load, and histopathologic scoring. Host biomarkers of inflammation were assessed in the colon before and after the pathogen challenge.Results: Cyanocobalamin supplementation led to an enhanced pathogen colonization at day 1 (P < 0.05) and day 3 (P < 0.01) post-infection. The impact of B12 on gut microbial communities, although minor, was distinct and attributed to the changes in the Lachnospiraceae populations and reduced alpha diversity. Cyanocobalamin treatment disrupted the activity of the low-abundance community members of the gut microbiota. It enhanced the amount of interleukin-12 p40 subunit protein (IL12/23p40; P < 0.001) and interleukin-17a (IL-17A; P < 0.05) in the colon of naïve mice. This immune phenotype was microbe-dependent, and the response varied based on the baseline microbiota. The cecal metatranscriptome revealed that excessive cyanocobalamin decreased the expression of glucose utilizing genes by C. rodentium, a metabolic attribute previously associated with pathogen virulence. Conclusions: Cyanocobalamin supplementation enhanced the ability of C. rodentium to colonize the gut by impacting the microbe-host interactions that normally help to protect against pathogen colonization. This research provides insights into vitamin B12 supplementation and highlights potential consequences of over-supplementation.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".