HoldsUp

DavidPerlmutterMD · 2026-04-14 · David Perlmutter (host), Trisha Pasricha

You’ve Been Pooping All Wrong (And It’s Affecting Your Brain) | Dr. Trischa Pasricha

35 research-tied claims examined: 3 contradicted 3 overstated 5 context 19 supported 5 unverified

19

Supported by research

0:10:12Trisha Pasrichasupportedhigh

Colorectal cancer complication and mortality rates are declining among older individuals.

"And what's, in a way, good news is that for older people, the complications, the death rates, those are actually declining. The rates are getting a little bit better as you're older, but they're not so much for that younger group." (said at 0:10:12)

Surveillance data from national cancer registries and health statistics confirm that colorectal cancer (CRC) mortality rates have steadily declined among older adults (particularly those aged 65 years and older, decreasing by approximately 2% to 3% annually), largely attributable to screening, early detection, and improved treatments. In contrast, CRC mortality and incidence have been rising among adults under age 50.

0:26:40Trisha Pasrichasupportedmoderate

Acute stressful thoughts evoking fear or anxiety cause stomach motility to slow down while simultaneously speeding up colonic motility.

"having these thoughts that felt stressful, evoked fear, evoked anxiety, could cause both the stomach to slow down, and this is something that I study, the stomach to slow down and not contract at the regular rhythm that it should, but simultaneously it caused the colon to speed up and rev up." (said at 0:26:40)

Extensive physiological research in both humans and animal models demonstrates that acute psychological stress, fear, and anxiety alter gastrointestinal motility in a dual pattern: inhibiting gastric contractions and delaying gastric emptying while simultaneously stimulating colonic transit and motor activity. This response is centrally coordinated through the brain-gut axis and the autonomic nervous system, largely mediated by central corticotropin-releasing factor (CRF) signaling.

0:29:45Trisha Pasrichasupportedmoderate

In irritable bowel syndrome (IBS), enteric nervous system nerves fire at a lower threshold and there is an increased concentration of pain-signaling TRPV1 receptors in the colon.

"We know that the nerves in the enteric nervous system will be triggered at a lower threshold, that there'll be a higher concentration of TRPV1 receptors in the colon, which is a receptor that signals pain to the brain." (said at 0:29:45)

Clinical tissue biopsy studies confirm that patients with irritable bowel syndrome (IBS) have a significantly higher density of transient receptor potential vanilloid type 1 (TRPV1) receptor-expressing sensory nerve fibers in colonic biopsies compared to controls. This increased expression correlates with abdominal pain severity and visceral hypersensitivity, which lowers the stimulus threshold required to trigger pain signals sent to the central nervous system.

0:12:55Trisha Pasrichasupportedhigh

The recommended starting age for routine colorectal cancer screening in average-risk individuals was lowered from 50 to 45 years.

"It actually was somewhat recently, within the last couple of years, that we moved it from 50 as the starting age to now it is 45." (said at 0:12:55)

Major guidelines updated the recommended starting age for routine colorectal cancer screening in average-risk adults from 50 to 45 years. In 2021, the US Preventive Services Task Force (USPSTF) officially expanded its recommendation statement to include screening in adults aged 45 to 49 years (Grade B recommendation) alongside adults aged 50 to 75 years (Grade A recommendation), driven by rising incidence rates of early-onset colorectal cancer and simulation modeling demonstrating moderate net benefit.

0:28:44Trisha Pasrichasupportedhigh

The enteric nervous system contains a network of millions of neurons embedded within the muscular layers of the gastrointestinal tract.

"That's the brain of the gut. It has a network of millions of neurons that are living, but it's buried in the muscle layer." (said at 0:28:44)

The statement accurately reflects established human gastrointestinal anatomy and neurobiology. The enteric nervous system (ENS), frequently referred to as the 'brain of the gut' or 'second brain,' contains an estimated 200 to 500+ million neurons organized into interconnected plexuses—most notably the myenteric (Auerbach's) plexus, which resides embedded between the longitudinal and circular muscle layers of the digestive tract wall.

0:32:24Trisha Pasrichasupportedmoderate

Psychological stress, such as defending a college thesis during an oral examination, rapidly increases intestinal permeability, anxiety, and cortisol levels.

"And so, there was a group of students who had to like defend their college thesis in front of this panel of judges. And they measured their intestinal permeability in the moments leading up to having to give that oral exam and then afterwards. And they found, of course, that their levels of stress went up, their anxiety went up, their cortisol went up. And then, so too did their intestinal permeability." (said at 0:32:24)

A 2014 human experimental study investigated the effect of acute psychological stress—specifically a public speaking task in front of an audience/evaluators (the Trier Social Stress Test paradigm)—on small intestinal permeability quantified via a 2-hour urinary lactulose-mannitol excretion test. The study demonstrated that public speech stress significantly increased salivary cortisol and small intestinal permeability compared to control conditions. Subgroup analysis confirmed that the increase in intestinal permeability was specifically present in subjects exhibiting a significant cortisol elevation.

0:34:03Trisha Pasrichasupportedmoderate

Ultra-processed foods, alcohol, and poor sleep have been shown to increase intestinal permeability.

"ultra-processed foods have been studied to increase intestinal permeability, alcohol, poor sleep, all of the things that are actually like quite boring. You've heard from your doctor a million times. All of those things do modulate your permeability" (said at 0:34:03)

Scientific literature supports the claim that ultra-processed foods, alcohol consumption, and sleep deprivation alter and increase intestinal permeability. Consuming ultra-processed foods is associated with gut barrier dysfunction, dysbiosis, and increased intestinal permeability. Chronic and acute alcohol consumption disrupts intestinal mucosal integrity and tight junctions, promoting intestinal barrier breakdown. Similarly, experimental sleep deprivation studies demonstrate marked increases in gut permeability and structural damage to the intestinal epithelial barrier.

0:44:00Trisha Pasrichasupportedhigh

Marathon runners are well described to have high amounts of intestinal permeability.

"marathon runners are like really well described to have high amounts of intestinal permeability, not always a good thing." (said at 0:44:00)

Prolonged endurance running, including marathon and ultramarathon competition, is well documented to cause transient intestinal epithelial injury and increased intestinal permeability (often termed exercise-induced gastrointestinal syndrome). Splanchnic hypoperfusion, thermal strain, and mechanical stress during prolonged running compromise the gut mucosal barrier, leading to elevated permeability markers (such as the lactulose/rhamnose ratio and 51Cr-EDTA excretion) and markers of enterocyte damage (such as intestinal fatty acid-binding protein, I-FABP).

0:48:03Trisha Pasrichasupportedhigh

The American Gastroenterological Association formally does not recommend probiotics for most indications, except for specific conditions like pouchitis in inflammatory bowel disease.

"formally the American Gastroenterological Association does not recommend probiotics for most indications. Like we do for very specific things like pouchitis for example and inflammatory bowel disease but the data's not there." (said at 0:48:03)

The American Gastroenterological Association (AGA) published clinical practice guidelines on the role of probiotics in the management of gastrointestinal disorders. In these guidelines, the AGA found insufficient evidence to recommend probiotics for most gastrointestinal indications (including Crohn's disease, ulcerative colitis, irritable bowel syndrome, and acute infectious gastroenteritis in children), making conditional recommendations supporting probiotic use only in a few narrowly defined contexts, such as pouchitis in patients with inflammatory bowel disease, the prevention of Clostridioides difficile infection in adults and children receiving antibiotics, and the prevention of necrotizing enterocolitis in preterm low-birth-weight infants.

0:58:05Trisha Pasrichasupportedmoderate

About one in three people with treatment-resistant constipation have pelvic floor dysfunction as the primary cause.

"And about one in three people who have what we would call constipation, they've tried different laxatives, they failed to get better with it, the issue is the pelvic floor." (said at 0:58:05)

Epidemiological and physiological studies of patients with chronic constipation who are refractory to standard initial treatments (e.g., fiber, osmotic and stimulant laxatives) consistently find that dyssynergic defecation / pelvic floor dysfunction is present in approximately 20% to 40% (roughly one in three) of referred patients, either in isolation or overlapping with slow-transit constipation.

0:59:45Trisha Pasrichasupportedhigh

Biofeedback physical therapy for pelvic floor dyssynergia is approximately 80% effective after two to three months of treatment.

"We treat it with a special kind of physical therapy called biofeedback. That's been shown in studies to be about 80% effective after about two to three months of physical therapy." (said at 0:59:45)

Randomized controlled trials evaluating biofeedback physical therapy for dyssynergic defecation demonstrate response and efficacy rates of approximately 70% to 80% following 3 months of treatment. For example, a randomized controlled trial comparing home-based and office-based biofeedback therapy over a 3-month intervention period reported responder rates of 70% (35/50) in the office-based biofeedback group and 68% (34/50) in the home-based biofeedback group, with significant improvements across all primary bowel and physiologic outcomes.

0:49:40Trisha Pasrichasupportedhigh

Fecal microbiota transplantation (FMT) is highly effective as a treatment for Clostridioides difficile (C. diff) infection.

"And that works really well for conditions like C. difficile infection, which is this bacteria that can cause a really horrible infection. FMT, fecal microbiota transplant answer works really well there." (said at 0:49:40)

The claim that fecal microbiota transplantation (FMT) is highly effective for treating Clostridioides difficile (C. diff) infection is supported by high-certainty evidence. Systematic reviews and Cochrane meta-analyses of randomized clinical trials confirm that FMT leads to a large increase in resolution of recurrent C. difficile infection compared to standard antibiotic therapy (e.g., vancomycin), nearly doubling resolution rates (RR 1.92 in Cochrane review; RR 1.51 to 1.85 in recent meta-analyses) and markedly lowering recurrence rates.

0:56:05David Perlmutter (host)supportedvery low

A collaborative study involving the University of Arizona and Dr. Alessio Fasano found significant improvement in gastrointestinal symptoms in children with autism spectrum disorder following fecal microbiota transplantation.

"We were—dare I say promoting, but at least investigating FMT in autism many years ago, and then we were I think gratified to see a study, collaborative study, University of Arizona with Dr. Alessio Fasano from Harvard significant improvement in these kids, at least in terms of their GI issues, which are rampant in autism spectrum disorder." (said at 0:56:05)

A collaborative open-label clinical trial involving Arizona researchers (Arizona State University and Northern Arizona University) and Dr. Alessio Fasano (Harvard/Massachusetts General Hospital) evaluated Microbiota Transfer Therapy (MTT, combining antibiotics, bowel cleanse, and fecal microbiota transplantation) in 18 children diagnosed with autism spectrum disorder and gastrointestinal disorders. The study reported an approximately 80% reduction in GI symptoms on the Gastrointestinal Symptom Rating Scale at the end of treatment, with sustained improvements at follow-up. Because the study was a small, open-label trial without a randomized placebo-control group, the certainty of evidence for clinical efficacy is very low.

0:50:15Trisha Pasrichasupportedhigh

Clinical trials of fecal microbiota transplantation for irritable bowel syndrome have generally failed to show strong positive patient outcomes.

"We've done so many clinical trials, and we—I mean people in this field—so many clinical trials to try to treat irritable bowel syndrome with fecal transplant, to try to treat Parkinson's disease with fecal transplant. And the outcomes aren't great. People don't actually do much better." (said at 0:50:15)

Systematic reviews, meta-analyses, and umbrella reviews of randomized controlled trials (RCTs) evaluating fecal microbiota transplantation (FMT) for irritable bowel syndrome (IBS) consistently find that FMT does not provide a reliable or robust overall clinical benefit over placebo. While some subgroup analyses suggest potential benefits depending on delivery modality (e.g., upper or lower endoscopic administration vs. oral capsules) or donor characteristics, pooled analysis of global IBS symptoms consistently shows no statistically significant superiority over placebo, supporting the speaker's statement that trials have generally shown underwhelming outcomes.

1:01:16Trisha Pasrichasupportedhigh

Approximately 7% of Americans experience fecal incontinence.

"And that's a big problem for the about 7% of Americans who deal with fecal incontinence." (said at 1:01:16)

The claim that approximately 7% to 9% of noninstitutionalized US adults experience fecal incontinence is supported by large national epidemiological data. In the National Health and Nutrition Examination Survey (NHANES) 2005–2006, the estimated prevalence of fecal incontinence (defined as accidental leakage of solid, liquid, or mucus stool at least once in the preceding month) among community-dwelling US adults aged 20 and older was 8.3% (95% CI: 7.1–9.5%) (PMID 19410574). Subsequent multi-year analyses of NHANES data (2005–2010) reported prevalence rates of 8.4% (PMID 42544354) and 9.2% (PMID 38657883). Stating "about 7%" accurately reflects the order of magnitude established in national US prevalence studies.

1:02:23Trisha Pasrichasupportedmoderate

The colon operates strongly on a circadian rhythm, becoming almost completely quiescent at night and producing strong contractions in the first one to two hours after waking.

"And that is that your colon actually operates very, very strongly on a circadian rhythm. So, unlike a lot of other organs in your body, it almost goes completely quiescent at night. There's very little activity. And in those first one or two hours upon waking, the nerve cells in the gut have this, you know, circadian entrainment. It wakes up and naturally produces very strong contractions that you very rarely are getting the rest of your day." (said at 1:02:23)

Human 24-hour colonic manometry and wireless motility capsule studies confirm that colonic motor activity exhibits a distinct circadian pattern. Colonic motility and contractile activity are minimal or almost completely absent during sleep at night, and significantly increase upon morning awakening, characterized by a peak in contractility and high-amplitude propagating contractions that occur predominantly in the early morning hours and after meals.

1:02:52Trisha Pasrichasupportedmoderate

Eating a meal, exercising, and drinking coffee all stimulate colonic contractions.

"You're going to get a little bit of it when you eat a meal. You're going to get a little bit of it if you exercise. You're going to get a little bit of it if you drink coffee." (said at 1:02:52)

Published human colonic manometry studies demonstrate that eating a meal, consuming coffee, and physical exercise (specifically during the post-exercise period) stimulate colonic motor activity and propagated contractions. In randomized physiological trials, ingestion of a meal and caffeinated coffee both significantly increase the area under the curve of colonic pressure waves and the frequency of propagated contractions. Similarly, following acute exercise, the number and amplitude of propagated colonic contractions increase, promoting colonic propulsion.

1:03:31Trisha Pasrichasupportedmoderate

Normal bowel movement frequency ranges from once every three days up to three times a day.

"Three times a day would be considered within the range of normal. Americans think that having a bowel movement every third day or up to three times a day could be normal." (said at 1:03:31)

Standard clinical gastroenterology criteria and population data define the normal range of bowel movement frequency as between three times per week (approximately once every two to three days) and three times per day (the common '3 and 3' rule). A study of 4,775 US adults from the National Health and Nutrition Examination Survey (NHANES) who reported normal bowel habits found that 95.9% had between 3 and 21 bowel movements per week.

1:04:29Trisha Pasrichasupportedlow

Using a smartphone on the toilet can increase the risk of developing hemorrhoids.

"Stop taking your smartphone to the bathroom, guys. Not good for you. It can increase your risk of hemorrhoids." (said at 1:04:29)

Observational research supports the claim that smartphone use on the toilet is associated with an increased risk of hemorrhoids, largely driven by prolonged sitting time. A cross-sectional study of adult patients undergoing screening colonoscopy found that smartphone users spent significantly more time on the toilet and had an adjusted 46% increased risk of endoscopically confirmed hemorrhoids compared to non-users, after controlling for age, sex, BMI, physical activity, straining, and fiber intake. Because available evidence is based on observational and cross-sectional designs, the certainty of evidence is low.

Unverified means no publication matching the claim was located; it does not prove the claim false. Spotted an error? See the corrections policy - disputes from the people quoted are prioritized.