HoldsUp

DavidPerlmutterMD · 2025-04-21 · David Perlmutter (host), Steven Gundry

The Gut-Brain Paradox: Secrets To Restoring Health | Steven Gundry

35 research-tied claims examined: 8 contradicted 4 overstated 4 context 15 supported 4 unverified

8

Contradicted by research

0:02:02David Perlmutter (host)contradictedhigh

Dr. Steven Gundry has published more than 300 articles in peer-reviewed journals on using diet and supplements to eliminate heart disease, diabetes, and autoimmune conditions.

"And he's written more than 300 articles published in peer-reviewed journals on using diet and supplements to eliminate heart disease, diabetes, autoimmune conditions, and multiple other diseases." (said at 0:02:02)

While Dr. Steven R. Gundry has an extensive publication record in peer-reviewed journals from his career as a cardiothoracic surgeon, his published peer-reviewed research focuses on surgical techniques, myocardial protection, pediatric cardiac transplantation, xenotransplantation, and surgical adhesives—not dietary or supplement interventions for eliminating heart disease, diabetes, or autoimmune conditions. A comprehensive search of the peer-reviewed medical literature identifies no body of over 300 peer-reviewed studies by Gundry investigating diet and supplements for disease elimination.

0:18:25Steven Gundrycontradictedmoderate

Approximately 80% of human immune cells (white blood cells) reside in the gut.

"And you know 80% of our immune cells, our white blood cells, are down in our gut." (said at 0:18:25)

While the gastrointestinal tract is a major immunological site containing substantial mucosal-associated lymphoid tissue (and produces a large fraction of secretory antibodies such as IgA), the claim that 80% of all immune cells (white blood cells) reside in the gut is contradicted by quantitative anatomical cell surveys. Comprehensive mapping of immune cells in the human body shows that the majority of human white blood cells reside in the bone marrow (most neutrophils and precursors) and secondary lymphoid tissues such as the spleen and lymph nodes (the majority of lymphocytes), with the gut housing only a modest fraction (under 5–10%) of total immune cells.

0:26:50Steven Gundrycontradictedhigh

Glyphosate (Roundup) was originally patented as an antibiotic rather than as an herbicide.

"And Roundup was patented as an antibiotic. It wasn't a weed killer." (said at 0:26:50)

The claim that glyphosate (Roundup) was originally patented as an antibiotic rather than an herbicide is contradicted by historical patent records and chemical literature. Glyphosate was first synthesized in 1950 by Swiss chemist Henri Martin at Cilag, where it was investigated as a metal chelating agent (and patented as such under Swiss Patent CH377080, later US Patent 3,160,632). Its herbicidal properties were discovered in 1970 by John E. Franz at Monsanto, leading to its registration and original patent as a broad-spectrum herbicide (US Patent 3,799,758, issued in 1974). Monsanto later obtained a patent for its antimicrobial properties in 2010 (US Patent 7,771,736), decades after its initial synthesis as a chelator and its development and marketing as an herbicide. While glyphosate does possess antimicrobial properties by inhibiting the shikimate pathway in susceptible bacteria (PMID: 41953436, PMID: 42041382), it was not originally patented or developed as an antibiotic.

0:27:20Steven Gundrycontradictedhigh

Selective serotonin reuptake inhibitors (SSRIs) exert their clinical therapeutic effects by altering the gut microbiome to a favorable tryptophan-pathway microbiome rather than by blocking brain serotonin reuptake.

"And lo and behold, we now know that these drugs actually change the microbiome to a more favorable um tryptophan pathway microbiome. And so even these drugs, the effect was actually on the microbiome." (said at 0:27:20)

Selective serotonin reuptake inhibitors (SSRIs) exert their primary therapeutic effects by binding to and inhibiting the serotonin transporter (SERT) in the central nervous system, increasing synaptic serotonin concentration and downstream neuroplasticity. While recent research demonstrates that SSRIs can alter gut microbiota composition and downstream tryptophan/indole metabolites (PMID 31273200, PMID 40176389), and that baseline microbiome composition correlates with treatment response (PMID 39695082), these gut interactions are modulating or secondary effects. Evidence regarding the microbiota-gut-brain axis in psychotropic drug response remains heterogeneous and largely associative (PMID 42316492). Claiming that the therapeutic effect of SSRIs is "actually on the microbiome" rather than central serotonin reuptake inhibition contradicts established neuropharmacology.

0:45:30David Perlmutter (host)contradictedhigh

Traditional Inuit populations, who historically had virtually no access to plant fiber and consumed exclusively meat and fat from hunted mammals, had very low rates of coronary artery disease.

"Well, I think another example of course would be the Inuit who don't have any access to fiber or traditionally traditionally until recently, and uh would eat nothing but fat and and meat uh from the mammals that they would kill and uh you know the my understanding is that their rates of coronary vascular disease, coronary artery disease, were very, very low." (said at 0:45:30)

The host claims that traditional Inuit populations, who ate predominantly animal meat and fat with virtually no plant fiber, had very low rates of coronary artery disease (CAD). However, published epidemiological reviews and historical research demonstrate that this widely repeated narrative is a myth. A comprehensive review of 40 years of published evidence on cardiovascular disease among Inuit populations (Fodor et al., 2014) showed that Greenland, Canadian, and Alaskan Inuit populations historically experienced rates of coronary artery disease similar to or higher than non-Inuit Caucasian control populations. Furthermore, Bang and Dyerberg's seminal 1970s studies, which popularized the idea of a lower prevalence of CAD, never actually measured CAD incidence or prevalence directly; instead, they relied on official death certificates, which severely underreported causes of death in isolated populations. Additionally, CT imaging studies performed on 16th-century Inuit mummies preserved in Greenland (Wan et al., 2019) confirm the presence of vascular calcification and atherosclerosis prior to modern Western dietary influences.

0:59:06Steven Gundrycontradictedhigh

The pharmaceutical company Eli Lilly was founded as a bacteriophage company prior to the antibiotic era.

"Eli Lilly, believe it or not, started as a bacteriophage company before the times of antibiotics." (said at 0:59:06)

Eli Lilly and Company was not founded as a bacteriophage company. The company was founded in May 1876 by Colonel Eli Lilly to manufacture standardized pharmaceutical preparations and medications—decades before bacteriophages were even discovered by Frederick Twort (1915) and Félix d'Hérelle (1917). While Eli Lilly did manufacture and commercialize bacteriophage biological products (such as Colo-lysate and Staphylo-lysate) in the 1930s during the pre-antibiotic era before abandoning them when chemical antibiotics emerged, it did not start as a bacteriophage enterprise.

0:51:20Steven Gundrycontradictedhigh

Color vision exists exclusively in fruit-eating animals.

"interestingly enough, uh we're fruit predators, uh and only fruit predators have color vision—um us and great apes and bees and uh so on, hummingbirds." (said at 0:51:20)

The claim that color vision exists exclusively in fruit-eating animals is contradicted by evolutionary biology and comparative visual physiology. Color vision is widespread across the animal kingdom across diverse trophic niches, including carnivores, insectivores, and aquatic predators. Ancestral vertebrates possessed multiple cone photoreceptor types enabling tetrachromatic or pentachromatic color vision, which is preserved in many modern fish, amphibians, reptiles, and birds. While the re-evolution of trichromatic color vision in catarrhine primates is hypothesized to have been influenced by foraging for ripe fruit and tender leaves, most non-frugivorous vertebrates and many non-frugivorous invertebrates (such as predatory mantis shrimp, jumping spiders, and nectar-feeding bees and hummingbirds) possess well-developed color vision.

  • contradicts: Early evolution of vertebrate photoreception: lessons from lampreys and lungfishes. (Integrative zoology 2009) · cited 12x in the literature
    "Detailed ultrastructural analysis reveals that all five receptor types in G. australis are cone-like, whereas N. forsteri possesses four cone types and a single type of rod. Each receptor type also contains a different visual pigment (opsin gene); that is, LWS, SWS1, SWS2, RhA and RhB in G. australis and LWS, SWS1, SWS2, Rh1 and Rh2 in N. forsteri, all of which are expressed within the retina and are sensitive to different parts of the electromagnetic spectrum, providing the potential for pentachromatic and tetrachromatic color vision, respectively." (abstract, results, passage verified)
    pubmedfull study (doi)
  • contradicts: Diverse Cell Types, Circuits, and Mechanisms for Color Vision in the Vertebrate Retina. (Physiological reviews 2019) · cited 173x in the literature
    "We review studies concerning the circuit mechanisms mediating opponent interactions in a range of species, from tetrachromatic fish with diverse color opponent cell types to common dichromatic mammals where cone opponency is restricted to a subset of specialized circuits. Distinct among mammals, primates have reinvented trichromatic color vision using novel strategies to incorporate evolution of an additional photopigment gene into the foveal structure and circuitry that supports high-resolution vision." (abstract, results, passage verified)
    pubmedfull study (doi)
1:04:22David Perlmutter (host)contradictedmoderate

Akkermansia muciniphila requires butyrate to function, which is why probiotic formulations pair it with Clostridium butyricum.

"It's one of the reasons is it requires butyrate, and that's why you do see products that not only have the Akkermansia, but Clostridium butyricum to to prime the pump, as it were." (said at 1:04:22)

The claim that Akkermansia muciniphila *requires* butyrate to function is contradicted by established microbiological evidence. A. muciniphila is a mucin-degrading specialist that utilizes host mucus glycoproteins (producing acetate and propionate) and can grow autonomously on mucin without external butyrate. In cross-feeding dynamics, A. muciniphila typically liberates mucin sugars (such as fucose and sialic acid) that support butyrate-producing commensals like Clostridia, rather than having an obligate metabolic requirement for butyrate. While in vitro and murine data indicate that butyrate or Clostridium butyricum metabolites can promote or enhance A. muciniphila growth, and commercial multi-strain synbiotic formulations (such as Pendulum Therapeutics' WBF-011) combine A. muciniphila and C. butyricum to synergistically restore mucin turnover and butyrate production, this co-formulation is based on complementary functional niches rather than an obligate dependency of A. muciniphila on butyrate.

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.