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
3 Overstated
Individuals who have undergone a vagotomy have a significant reduction in the risk of developing Parkinson's disease.
"For example, the pretty significant reduction in risk of developing Parkinson's in individuals who've had their vagus nerve cut... So, there became this group of people who underwent vagotomy, had their vagus nerve cut. And when you follow them, they had a significant reduction in risk for developing Parkinson's." (said at 0:52:18)
The host states that individuals who have had a vagotomy have a significant reduction in the risk of developing Parkinson's disease. Large population-based cohort studies show that overall vagotomy is not associated with a reduced risk of Parkinson's disease. A reduction in risk was observed only in subset analyses for full truncal vagotomy (where the entire main nerve trunk is severed) after long follow-up times (e.g. >5 to 20 years), whereas selective/superselective vagotomy shows no protective effect.
- partial: Vagotomy and subsequent risk of Parkinson's disease. (Annals of neurology 2015) · cited 810x in the literature
"Risk of PD was decreased in patients who underwent truncal (HR = 0.85; 95% CI = 0.56-1.27; follow-up of >20 years: HR = 0.58; 95% CI: 0.28-1.20) compared to superselective vagotomy. Risk of PD was also decreased after truncal vagotomy when compared to the general population cohort (overall adjusted HR = 0.85; 95% CI: 0.63-1.14; follow-up >20 years, adjusted HR = 0.53; 95% CI: 0.28-0.99). In patients who underwent superselective vagotomy, risk of PD was similar to the general population (HR = 1.09; 95% CI: 0.84-1.43; follow-up of >20 years: HR = 1.16; 95% CI: 0.80-1.70)." (abstract, results, passage verified)
pubmedfull study (doi) - partial: Vagotomy and Parkinson disease: A Swedish register-based matched-cohort study. (Neurology 2017) · cited 451x in the literature
"Overall, vagotomy was not associated with PD risk (HR 0.96, 95% CI 0.78-1.17). However, there was a suggestion of lower risk among patients with truncal vagotomy (HR 0.78, 95% CI 0.55-1.09), which may be driven by truncal vagotomy at least 5 years before PD diagnosis (HR 0.59, 95% CI 0.37-0.93). Selective vagotomy was not related to PD risk in any analyses." (abstract, results, passage verified)
pubmedfull study (doi) - contradicts: Gastrointestinal syndromes preceding a diagnosis of Parkinson's disease: testing Braak's h… (Gut 2023) · cited 62x in the literature
"Neither inflammatory bowel disease nor vagotomy were associated with PD." (abstract, results, passage verified)
pubmedfull study (doi)
An April 2024 study published in the New England Journal of Medicine in 130 Parkinson's patients showed that treatment with a GLP-1 receptor agonist halted disease progression.
"Well, a calendar—not this calendar, but in April of 2024 published in the New England Journal of Medicine was a powerful study, the first of its kind, that looked at treating Parkinson's patients, a group of 130 patients, with a GLP-1 agonist, Ozempic-like drug, and they stopped the disease dead in its tracks in terms of its progression." (said at 0:53:50)
A phase 2 randomized controlled trial published in the New England Journal of Medicine in April 2024 (the LIXIPARK trial) evaluated the GLP-1 receptor agonist lixisenatide in 156 patients with early Parkinson's disease. Over 12 months, participants taking lixisenatide showed minimal change in motor disability scores (MDS-UPDRS Part III change of -0.04 points) compared to worsening in the placebo group (+3.04 points), yielding a statistically significant difference of 3.08 points on a 132-point scale. However, secondary endpoints did not differ substantially between groups, and the authors emphasized that longer and larger phase 3 trials are required. Describing the drug as having 'stopped the disease dead in its tracks' overstates a modest, short-term stabilization of motor symptoms in a preliminary phase 2 trial.
Having type 2 diabetes increases the risk of developing Parkinson's disease by 40%.
"You know, if you're type 2 diabetic, you have a 40% increased risk of becoming a Parkinson's patient." (said at 0:55:15)
Type 2 diabetes is associated with an increased risk of developing Parkinson's disease, but systematic reviews and meta-analyses of observational cohorts estimate this risk increase to be approximately 21% to 23%, rather than 40%. A meta-analysis published in Movement Disorders found a pooled odds ratio of 1.21 (95% CI 1.07–1.36) for Parkinson's disease risk in individuals with type 2 diabetes, supported by Mendelian randomization evidence of a lower magnitude (OR 1.08). Another meta-analysis published in Frontiers in Aging Neuroscience found a pooled risk ratio of 1.23 (95% CI 1.12–1.35). While the host correctly identifies type 2 diabetes as a risk factor for Parkinson's disease, the stated 40% figure overstates the size of the effect observed in pooled evidence.
- partial: Type 2 Diabetes as a Determinant of Parkinson's Disease Risk and Progression. (Movement disorders : official journal of the Movement Disorder Society 2021) · cited 239x in the literature
"In the observational part of the study, pooled effect estimates showed that T2DM was associated with an increased risk of PD (odds ratio [OR] 1.21, 95% confidence interval [CI] 1.07-1.36)" (abstract, results, passage verified)
pubmedfull study (doi) - partial: Association between diabetes mellitus, prediabetes and risk, disease progression of Parkin… (Frontiers in aging neuroscience 2023) · cited 17x in the literature
"DM was associated with a higher risk of PD, compared to non-diabetic participants with a random effects model (OR/RR = 1.23, 95% CI 1.12-1.35, I 2 = 90.4%, p < 0.001)." (abstract, results, passage verified)
pubmedfull study (doi)
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.