The evidence library

The research. With the limits in view.

Explore digestive-health research questions and a searchable reference library, with original PubMed links, study labels and a clear warning for a retracted paper.

Questions to bring to the research

Is the Bristol Stool Chart Accurate? What the Research Shows

Which stool-form descriptions were studied, in whom, and how did the researchers measure transit or agreement between observers?

Use the reference desk below to inspect original records. A research question is not a diagnosis or proof of Get Regular’s performance.

How Often Should You Poop? What the Research Shows

How was bowel frequency recorded, which population was included, and how much variation did the study describe?

Use the reference desk below to inspect original records. A research question is not a diagnosis or proof of Get Regular’s performance.

Gut Transit Time: How Long Food Takes to Become Poop

Which method measured transit, which part of the digestive tract did it cover, and what do the results actually describe?

Use the reference desk below to inspect original records. A research question is not a diagnosis or proof of Get Regular’s performance.

Fiber and Constipation: What the Research Shows

Which fiber, dose and patient group were studied? What were the outcomes and limitations, rather than a general promise about all fiber?

Use the reference desk below to inspect original records. A research question is not a diagnosis or proof of Get Regular’s performance.

Food Diaries vs Memory: What the Research Shows for IBS

What did a day-by-day record capture compared with recalled symptoms, and what could neither method establish about causes?

Use the reference desk below to inspect original records. A research question is not a diagnosis or proof of Get Regular’s performance.

Lactose Intolerance: What the Research Shows

Does the paper study malabsorption, reported symptoms or both? Which measurements support the conclusion?

Use the reference desk below to inspect original records. A research question is not a diagnosis or proof of Get Regular’s performance.

Gluten Sensitivity Without Celiac Disease: What the Research Shows

How did the study separate gluten from other ingredients, expectations and existing diagnoses?

Use the reference desk below to inspect original records. A research question is not a diagnosis or proof of Get Regular’s performance.

Low FODMAP and IBS Diet Guidelines: What the Research Shows

Who does the recommendation apply to, how strong is the supporting evidence, and what supervision or limits does the guidance describe?

Use the reference desk below to inspect original records. A research question is not a diagnosis or proof of Get Regular’s performance.

Stress and IBS Flares: What the Research Shows

Were stress and symptoms recorded at the same time or recalled later? Does the design distinguish association from causation?

Use the reference desk below to inspect original records. A research question is not a diagnosis or proof of Get Regular’s performance.

Can Food Poisoning Cause IBS? What the Research Shows

How was the initial infection established, how long were people followed, and how was the later diagnosis defined?

Use the reference desk below to inspect original records. A research question is not a diagnosis or proof of Get Regular’s performance.

Bloating: What the Research Shows

How did the researchers define and measure bloating or distension? Which findings apply to the people actually studied?

Use the reference desk below to inspect original records. A research question is not a diagnosis or proof of Get Regular’s performance.

Gut Microbiome Tests: What the Research Shows

What does the test measure, how reproducible is the result, and what evidence supports using it for an individual decision?

Use the reference desk below to inspect original records. A research question is not a diagnosis or proof of Get Regular’s performance.

AI Stool and Meal Photo Analysis: What the Research Shows

Check which method and population were studied, what the results support and which questions remain open.

Use the reference desk below to inspect original records. A research question is not a diagnosis or proof of Get Regular’s performance.

The reference desk

Open the original record.

Browse the bibliography by title, author, year or topic. This is a starting point for reading, rather than a systematic review, a quality score or a list of product endorsements. The original record carries the study’s own methods and limitations.

81 of 81 non-retracted references

Guideline · 2025

International consensus statement on microbiome testing in clinical practice

Porcari S · Lancet Gastroenterol Hepatol

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Guideline · 2023

American Gastroenterological Association-American College of Gastroenterology Clinical Practice Guideline: Pharmacological Management of Chronic Idiopathic Constipation

Chang L · Am J Gastroenterol

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Guideline · 2023

AGA Clinical Practice Update on Evaluation and Management of Belching, Abdominal Bloating, and Distention: Expert Review

Moshiree B · Gastroenterology

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Guideline · 2021

ACG Clinical Guideline: Management of Irritable Bowel Syndrome

Lacy BE · Am J Gastroenterol

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Guideline · 2020

ACG Clinical Guideline: Small Intestinal Bacterial Overgrowth

Pimentel M · Am J Gastroenterol

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Guideline · 2019

Rome Foundation Working Team Report on Post-Infection Irritable Bowel Syndrome

Barbara G · Gastroenterology

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Guideline · 2018

Guidelines for the investigation of chronic diarrhoea in adults: British Society of Gastroenterology, 3rd edition

Arasaradnam RP · Gut

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Systematic review / meta-analysis · 2025

Efficacy of dietary interventions in irritable bowel syndrome: a systematic review and network meta-analysis

Cuffe MS · Lancet Gastroenterol Hepatol

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Systematic review / meta-analysis · 2021

Global prevalence of functional constipation according to the Rome criteria: a systematic review and meta-analysis

Barberio B · Lancet Gastroenterol Hepatol

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Systematic review / meta-analysis · 2019

Lactose intolerance but not lactose maldigestion is more frequent in patients with irritable bowel syndrome than in healthy controls: A meta-analysis

Varjú P · Neurogastroenterol Motil

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Systematic review / meta-analysis · 2018

A Systematic Review and Meta-Analysis Evaluating the Efficacy of a Gluten-Free Diet and a Low FODMAPs Diet in Treating Symptoms of Irritable Bowel Syndrome

Dionne J · Am J Gastroenterol

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Systematic review / meta-analysis · 2017

Prevalence, Risk Factors, and Outcomes of Irritable Bowel Syndrome After Infectious Enteritis: A Systematic Review and Meta-analysis

Klem F · Gastroenterology

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Systematic review / meta-analysis · 2010

Systematic review: effective management strategies for lactose intolerance

Shaukat A · Ann Intern Med

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Systematic review / meta-analysis · 2010

NIH consensus development conference statement: Lactose intolerance and health

Suchy FJ · NIH Consens State Sci Statements

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Randomized trial · 2025

Effect of gluten and wheat on symptoms and behaviours in adults with irritable bowel syndrome: a single-centre, randomised, double-blind, sham-controlled crossover trial

Seiler CL · Lancet Gastroenterol Hepatol

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Randomized trial · 2020

Contrasting effects of viscous and particulate fibers on colonic fermentation in vitro and in vivo, and their impact on intestinal water studied by MRI in a randomized trial

Gunn D · Am J Clin Nutr

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Randomized trial · 2018

Fructan, Rather Than Gluten, Induces Symptoms in Patients With Self-Reported Non-Celiac Gluten Sensitivity

Skodje GI · Gastroenterology

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Randomized trial · 2013

No effects of gluten in patients with self-reported non-celiac gluten sensitivity after dietary reduction of fermentable, poorly absorbed, short-chain carbohydrates

Biesiekierski JR · Gastroenterology

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Randomized trial · 2010

Gastrointestinal tolerance of chicory inulin products

Bonnema AL · J Am Diet Assoc

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Randomized trial · 2008

Gastrointestinal distress after creatine supplementation in athletes: are side effects dose dependent?

Ostojic SM · Res Sports Med

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Randomized trial · 2003

Influence of body posture on intestinal transit of gas

Dainese R · Gut

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Randomized trial · 1998

Intolerance of cow's milk and chronic constipation in children

Iacono G · N Engl J Med

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Randomized trial · 1997

Stool form scale as a useful guide to intestinal transit time

Lewis SJ · Scand J Gastroenterol

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Clinical study · 2025

Customized multimodal Diabot-GPT-4o enhances accuracy of image-based dietary assessments in dietetic trainees in Taiwan: validation against weighed food records

Chen YJ · Am J Clin Nutr

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Clinical study · 2019

Gastrointestinal recall questionnaires compare poorly with prospective patient diaries for gastrointestinal symptoms: data from population and primary health centre samples

Jones MP · Eur J Gastroenterol Hepatol

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Clinical study · 2016

Validity and reliability of the Bristol Stool Form Scale in healthy adults and patients with diarrhoea-predominant irritable bowel syndrome

Blake MR · Aliment Pharmacol Ther

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Clinical study · 2015

Regional gastrointestinal transit and pH studied in 215 healthy volunteers using the wireless motility capsule: influence of age, gender, study country and testing protocol

Wang YT · Aliment Pharmacol Ther

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Clinical study · 2001

Ambulatory 24-h colonic manometry in healthy humans

Rao SS · Am J Physiol Gastrointest Liver Physiol

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Clinical study · 1987

Simplified assessment of segmental colonic transit

Metcalf AM · Gastroenterology

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Review · 2026

What is new in Rome V?: Redefining diagnostic criteria and clinical pathways in disorders of gut-brain interaction

Goyal MK · Indian J Gastroenterol

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Review · 2021

Common questions and misconceptions about creatine supplementation: what does the scientific evidence really show?

Antonio J · J Int Soc Sports Nutr

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Review · 2021

Management of Chronic Abdominal Distension and Bloating

Lacy BE · Clin Gastroenterol Hepatol

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Review · 2019

Update on lactose malabsorption and intolerance: pathogenesis, diagnosis and clinical management

Misselwitz B · Gut

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Review · 2017

New mobile methods for dietary assessment: review of image-assisted and image-based dietary assessment methods

Boushey CJ · Proc Nutr Soc

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Review · 2017

Bloating and Abdominal Distension: Old Misconceptions and Current Knowledge

Malagelada JR · Am J Gastroenterol

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Review · 2014

Impact of psychological stress on irritable bowel syndrome

Qin HY · World J Gastroenterol

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Review · 2013

Fiber and functional gastrointestinal disorders

Eswaran S · Am J Gastroenterol

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Study · 2026

Evaluating the analytical performance of direct-to-consumer gut microbiome testing services

Servetas SL · Commun Biol

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Study · 2026

Comparison of demographic, clinical, and psychological characteristics among patients with irritable bowel syndrome meeting the Rome clinical, Rome V, and Rome IV criteria

Wu J · Am J Gastroenterol

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Study · 2026

Beyond Chronic Stress: Daily Stress Is Associated With Symptoms in Irritable Bowel Syndrome

Yunusova A · Clin Gastroenterol Hepatol

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Study · 2025

Retraction-Country, regional, and global estimates for lactose malabsorption in adults: a systematic review and meta-analysis

· Lancet Gastroenterol Hepatol

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Study · 2025

Performance Evaluation of 3 Large Language Models for Nutritional Content Estimation from Food Images

Fridolfsson J · Curr Dev Nutr

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Study · 2025

An Evaluation of ChatGPT for Nutrient Content Estimation from Meal Photographs

O'Hara C · Nutrients

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Study · 2025

Long-term, automated stool monitoring using a novel smart toilet: A feasibility study

Zhou J · Neurogastroenterol Motil

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Study · 2024

Advancements in Using AI for Dietary Assessment Based on Food Images: Scoping Review

Chotwanvirat P · J Med Internet Res

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Study · 2024

Artificial Intelligence Evaluation of Stool Quality Guides Management of Hepatic Encephalopathy Using a Smartphone App

Fagan A · Am J Gastroenterol

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Study · 2024

Microbiome testing in Europe: navigating analytical, ethical and regulatory challenges

Rodriguez J · Microbiome

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Study · 2023

Prevalence and Burden of Illness of Rome IV Irritable Bowel Syndrome in the United States: Results From a Nationwide Cross-Sectional Study

Almario CV · Gastroenterology

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Study · 2023

Abdominal Bloating in the United States: Results of a Survey of 88,795 Americans Examining Prevalence and Healthcare Seeking

Oh JE · Clin Gastroenterol Hepatol

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Study · 2023

American College of Gastroenterology Guidelines Update: Diagnosis and Management of Celiac Disease

Rubio-Tapia A · Am J Gastroenterol

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Study · 2022

Fishing for Irritable Bowel Syndrome: Which Alarm Features Weave the Best Net?

Brandler J · Clin Gastroenterol Hepatol

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Study · 2022

A Smartphone Application Using Artificial Intelligence Is Superior To Subject Self-Reporting When Assessing Stool Form

Pimentel M · Am J Gastroenterol

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Study · 2021

Blue poo: impact of gut transit time on the gut microbiome using a novel marker

Asnicar F · Gut

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Study · 2021

Worldwide Prevalence and Burden of Functional Gastrointestinal Disorders, Results of Rome Foundation Global Study

Sperber AD · Gastroenterology

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Study · 2020

Normative values for region-specific colonic and gastrointestinal transit times in 111 healthy volunteers using the 3D-Transit electromagnet tracking system: Influence of age, gender, and body mass index

Nandhra GK · Neurogastroenterol Motil

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Study · 2020

Chronic Constipation in the United States: Results From a Population-Based Survey Assessing Healthcare Seeking and Use of Pharmacotherapy

Oh SJ · Am J Gastroenterol

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Study · 2020

Prevalence of Rome IV Functional Bowel Disorders Among Adults in the United States, Canada, and the United Kingdom

Palsson OS · Gastroenterology

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Study · 2018

Characterizing Normal Bowel Frequency and Consistency in a Representative Sample of Adults in the United States (NHANES)

Mitsuhashi S · Am J Gastroenterol

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Study · 2017

Suspected Nonceliac Gluten Sensitivity Confirmed in Few Patients After Gluten Challenge in Double-Blind, Placebo-Controlled Trials

Molina-Infante J · Clin Gastroenterol Hepatol

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Study · 2016

Feasibility and Usability Pilot Study of a Novel Irritable Bowel Syndrome Food and Gastrointestinal Symptom Journal Smartphone App

Zia J · Clin Transl Gastroenterol

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Study · 2014

Anal gas evacuation and colonic microbiota in patients with flatulence: effect of diet

Manichanh C · Gut

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Study · 2013

Self-reported food-related gastrointestinal symptoms in IBS are common and associated with more severe symptoms and reduced quality of life

Böhn L · Am J Gastroenterol

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Study · 2011

Abdomino-phrenic dyssynergia in patients with abdominal bloating and distension

Villoria A · Am J Gastroenterol

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Study · 2011

Prospective diary evaluation of unexplained abdominal pain and bowel dysfunction: a population-based colonoscopy study

Walter SA · Dig Dis Sci

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Study · 2006

Relationship of abdominal bloating to distention in irritable bowel syndrome and effect of bowel habit

Houghton LA · Gastroenterology

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Study · 2005

The perceived effect of various foods and beverages on stool consistency

Müller-Lissner SA · Eur J Gastroenterol Hepatol

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Study · 2003

Creatine Supplementation Increases Total Body Water Without Altering Fluid Distribution

Powers ME · J Athl Train

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Study · 2002

A population-based study on bowel habits in a Swedish community: prevalence of faecal incontinence and constipation

Walter S · Scand J Gastroenterol

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Study · 2001

Food-related gastrointestinal symptoms in the irritable bowel syndrome

Simrén M · Digestion

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Study · 1998

The relationship between psychological distress and gastrointestinal symptoms in women with irritable bowel syndrome

Jarrett M · Nurs Res

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Study · 1997

The relationship between daily life stress and gastrointestinal symptoms in women with irritable bowel syndrome

Levy RL · J Behav Med

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Study · 1997

Clinical response to dietary fiber treatment of chronic constipation

Voderholzer WA · Am J Gastroenterol

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Study · 1996

Variability of gastrointestinal transit in healthy women and men

Degen LP · Gut

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Study · 1994

Effect of cheese on intestinal transit time and other indicators of bowel function in residents of a retirement home

Mykkänen HM · Scand J Gastroenterol

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Study · 1992

The normal range and a simple diagram for recording whole gut transit time

Evans RC · Int J Colorectal Dis

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Study · 1992

Defecation frequency and timing, and stool form in the general population: a prospective study

Heaton KW · Gut

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A reference is a way into the research, not the last word. Open the original record to see the population, methods, findings and limits behind a claim.

How to read this library

This is a bibliographic reference desk, rather than a systematic review or a rating of the evidence. Study labels help you navigate; a label alone does not tell you how well a study was designed or whether its findings apply to you.

Research on stool form, food diaries or an AI system concerns the method that was actually studied. Inclusion here does not mean the paper tested Get Regular. The known retracted record is hidden from the main list and can be inspected separately with a warning.

Sources & product information

  1. PubMed — U.S. National Library of Medicine