Accuracy and Corrections¶
A book about health has to be right. This page explains how Gut Check is checked and lists the corrections made so far. Publishing corrections is part of doing science honestly.
Why show the mistakes?
Every careful scientist gets things wrong sometimes. What matters is checking, fixing, and being open about it. If you spot something, please tell us!
How the book is checked¶
Every chapter went through these layers before publication (October 2026). Each layer was done separately from the one before it.
| Layer | What it does |
|---|---|
| 1. Verified sources first | Before any chapter was written, about 300 sources were opened and logged, with the exact claim each one supports, an evidence grade, and known traps. Popular figures that failed (such as "70% of your immune system is in your gut") were flagged. |
| 2. Writing with a fact log | Each chapter's writer logged every number, date, name, approval, and study against a page they opened, and removed or softened anything they couldn't confirm. |
| 3. Independent fact-check | A separate reviewer re-checked every chapter's facts, quiz answers, links, and simulation, and fixed what was wrong. The supporting pages (FAQ, mock exam, teacher materials) got their own reviewer. |
| 4. Expert subject edit and currency pass | Editors working as a pediatric gastroenterologist, a gut-brain researcher, and an adolescent psychiatrist looked for oversimplifications that had become false, missing caveats, and outdated facts, and updated everything to October 2026. |
| 5. Plain-language edit with a fact guard | A final edit made the writing clearer. A script compared every file before and after to prove no fact, number, name, or link changed. |
| 6. Final specialist pass | A last full read of every chapter by editors working as a senior ulcerative colitis and Crohn's specialist, a neuroscientist, and a literary editor, checking every claim, grade, and quiz answer and removing anything that sounded machine-written. |
| 7. Whole-book checks | Scripts checked every chapter's structure, the learning graph, the glossary, the FAQ links, every external link, and the built website. Every simulation was tested and looked at. |
The lead editor personally re-opened the sources behind the biggest and newest claims, including every recent FDA approval, the 2026 Rome V criteria, the August 2026 CDC estimate of adult IBD, and the October 2026 CDC youth survey.
How many fixes? The review logs record about 120 corrections from the independent fact-check of the 20 chapters, 12 on the supporting pages, about 95 more fixes and updates from the expert edit, and about 120 more from the final specialist pass. Most were small (a softened word, a clearer caveat). The most important ones are listed below.
Corrections made before publication¶
| Where | What was wrong | Correction |
|---|---|---|
| Chapter 4 plan | The draft plan graded "70% of your immune system lives in your gut" as Preliminary. | Graded Hype: the gut holds about 70% of antibody-making plasma cells but only about 3% of all immune cells (Sender et al. 2023). |
| Chapter 3 simulation | One antibiotic course pushed opportunistic bacteria to nearly the whole community and erased many species, which exaggerates human studies. | Retuned so changes are smaller and recovery is partial, with the limits stated. |
| Chapter 7 simulation | Gut leakiness rose with cortisol directly. | Now driven by stress hormone CRH acting on gut mast cells, matching a 2014 human study. |
| Chapter 10 | Peppermint oil was graded Moderate even though the evidence was rated very low quality. | Regraded Preliminary. |
| Chapter 15 | The card "Ultra-processed food causes depression" was graded Moderate, but only links (not cause) have been shown. | Card now grades the claim the evidence supports: "linked to," Moderate, with "causes" marked as not shown. |
| Chapter 16 | A trial was described as 8 weeks on each treatment; it was 4 weeks each. | Corrected in three places. |
| Chapter 16 | Probiotics for preventing a serious gut disease in premature babies were graded Preliminary. | Regraded Moderate (a 2023 Cochrane review of 60 trials), but not settled for routine use. |
| Chapter 17 | Said both major US guidelines give low-dose tricyclic antidepressants for IBS a conditional recommendation. | The ACG 2021 guideline gives a strong recommendation (moderate-quality evidence); the AGA 2022 one is conditional. |
| Chapter 17 | Missed an FDA-authorized device for teens. | Added IB-Stim (De Novo authorization, June 2019) for IBS belly pain in patients 11 to 18. |
| Chapter 18 | "Exercise changes your microbiome in ways that improve your mood" was graded Preliminary. | Regraded Hype (exercise helps mood, but the microbiome link isn't shown in people). |
| Chapter 20 simulation | Three claim cards didn't match the grades in their own chapters. | All 16 cards now match the chapters. |
| Chapter 11, home page | Used the 2023 youth survey figure (39.7%). | Updated to the 2025 survey, published October 15, 2026 (33.3%). |
| Chapter 12 | A case listed a relative with type 1 diabetes as a celiac risk factor. | Changed to match NIDDK: family history of celiac disease is the listed risk factor. |
| Hype Meter page, teacher guide | Used a Strong claim as the example of Moderate. | Replaced with a true Moderate example. |
| Chapter 2, Chapter 17 | Lists of FDA-approved vagus nerve stimulators left out one device. | Added the Vivistim System (approved August 27, 2021) for arm rehabilitation after stroke. |
| Chapter 5 | "Gut bacteria make neurotransmitters that reach your brain" was graded Preliminary, even though the chapter said the "reach your brain" part isn't shown in people. | Regraded Hype, as stated. |
| Chapter 9 | The chapter didn't cover colorectal cancer screening in IBD or the full pediatric diagnostic workup. | Added both, from NIDDK and the pediatric Porto criteria. |
| Chapter 12 | Said celiac disease can't happen without the DQ2 or DQ8 genes, and implied fructan beat placebo in a key trial. | Now "almost never" (NIDDK), and the trial result is described as the study reported it. |
| Chapter 17 | A quote implied fecal transplant itself is FDA approved, and Vowst's owner was out of date. | Only Rebyota and Vowst are approved; Vowst was sold by Seres to Nestlé Health Science in 2024. |
| Chapter 18 | A breathing exercise said ten slow breaths take "about a minute." | Corrected (about six breaths a minute at that pace). |
Corrections after publication¶
None yet. When readers or reviewers report errors, confirmed fixes will be listed here with the date.
| Date | Where | What was wrong | Correction | Reported by |
|---|---|---|---|---|
What a human expert should still review¶
This book has not yet been reviewed by an outside physician or researcher. Some judgment calls that an expert should look at:
- Hype Meter grades that sit near a boundary (for example, gut-directed hypnotherapy for IBS at Moderate, and "Parkinson's can start in the gut" at Moderate for some people).
- Chapter 13 (Autism, ADHD, and the Gut), which should be reviewed by autistic and ADHD readers.
- New 2026 guidance (Rome V, the 2026 pediatric Crohn's guideline) that was read mainly from abstracts.
Report an error¶
Found a mistake? Please use the error report form or see the Contact page. Include a source if you can.