HoldsUp

DavidPerlmutterMD · 2019-03-02 · David Perlmutter (host), Sara Gottfried

Weight Loss and the Brain - with Dr. Sara Gottfried | The Empowering Neurologist EP. 82

37 research-tied claims examined: 2 contradicted 4 overstated 7 context 19 supported 1 corroborated online 4 unverified

2

Contradicted by research

0:09:20Sara Gottfriedcontradictedhigh

Women tend to have a larger hippocampus up until a certain age, while men tend to have a larger cerebellum.

"in general, we know that women tend to have a bigger hippocampus, at least up until a certain age, and men tend to have a larger cerebellum, which is responsible for movement and coordination and other things." (said at 0:09:20)

The claim that women tend to have a larger hippocampus (up to a certain age) is contradicted by meta-analytic MRI evidence. Meta-analyses of structural brain imaging show that uncorrected absolute hippocampal volume is larger in men across all age groups, primarily reflecting larger overall brain size in males. When adjusted for total brain volume or intracranial volume, there is no statistically significant sex difference in hippocampal volume.

0:47:40Sara Gottfriedcontradictedhigh

Only about 10% to 15% of the risk for chronic disease is genetic, while 85% to 90% is determined by environmental and lifestyle factors.

"And when it comes to something like Alzheimer's disease, or if you look at chronic disease in general, only about 10 to 15% of your risk of chronic disease is related to your genes. The rest, which is what we have a fair amount of control over, the 85 to 90%, is your environment, much of which is determined by your lifestyle choices, how you architect your day." (said at 0:47:40)

The claim that genetic factors account for only 10% to 15% of the risk of chronic diseases such as Alzheimer's disease is contradicted by genetic epidemiological evidence. In the largest population-based twin studies, the heritability of late-onset Alzheimer's disease is estimated to be between 58% and 79%, with non-shared environmental factors explaining the remainder. While environmental and lifestyle factors play important, modifiable roles in chronic disease progression and risk reduction, genetic liability accounts for a substantially larger proportion of disease risk than 10% to 15% across many major chronic conditions, particularly Alzheimer's disease.

4

Overstated

0:22:34David Perlmutter (host)overstatedvery low

The ketogenic diet enhances brain reconnection and neurogenesis.

"recognizing that a ketogenic diet also enhances reconnection in the brain and repopulating the brain with new brain cells." (said at 0:22:34)

The claim is overstated. Rodent studies indicate that a ketogenic diet or its metabolite beta-hydroxybutyrate (BHB) can modulate synaptic plasticity pathways (such as long-term potentiation and neurotrophic signaling) and rescue adult hippocampal neurogenesis in specific injury or genetic disease models (such as Kabuki syndrome or post-seizure models). However, there is no clinical evidence in humans demonstrating that a ketogenic diet repopulates the brain with new brain cells or causes broad neural reconnection. In mammals, adult neurogenesis is restricted to specific niches rather than widespread repopulation of brain tissue.

0:27:53Sara Gottfriedoverstatedlow

Chronic high stress causes telomere shortening, accelerates aging, impairs gut barrier integrity, and contributes to 90% or more of disease.

"We know it shrinks the telomeres. We know it accelerates the aging process. We know it either causes or exacerbates 90% of disease, if not more. We know it pokes holes in the gut lining." (said at 0:27:53)

The speaker's claims bundle established biological associations with substantial hyperbole: 1. **Telomere shortening and aging**: Systematic reviews and meta-analyses show that chronic psychological and social stress is associated with shorter leukocyte telomere length, a cellular marker of biological aging, though meta-analytic effect sizes are very small (e.g., r = -0.06) and subject to potential publication bias. 2. **Gut barrier integrity**: Preclinical and animal models demonstrate that stress increases intestinal permeability (often via mast-cell activation and tight-junction disruption), but human evidence in healthy populations remains mixed and less definitive. 3. **Contributing to 90% or more of disease**: The assertion that stress "either causes or exacerbates 90% of disease, if not more" is an oft-repeated lay statistic without rigorous epidemiological or empirical verification. While chronic stress is a well-established risk factor for cardiovascular, metabolic, mental health, and autoimmune conditions, quantifying it as responsible for ≥90% of all disease is unsupported.

0:47:12Sara Gottfriedoverstatedmoderate

Approximately 6,000 genes are involved in regulating blood sugar.

"There's 6,000 genes for blood sugar, there's many genes involved in height." (said at 0:47:12)

While glycemic regulation and polygenic metabolic traits involve a distributed, polygenic architecture across hundreds of loci throughout the genome, stating that there are specifically "6,000 genes for blood sugar" is an overstatement and does not align with established genomic evidence. Large-scale genome-wide association study (GWAS) meta-analyses—such as those by the MAGIC consortium involving up to hundreds of thousands of participants—identify hundreds of genomic loci and candidate genes (e.g., 242 loci for glycemic traits, 120 loci for random glucose) influencing blood glucose regulation, not 6,000 specific genes.

0:58:07David Perlmutter (host)overstatedlow

MTHFR gene polymorphism is a significant risk factor for Alzheimer's disease.

"The genetic issues that I have, the MTHFR, for example—there are plenty of YouTube videos on this if you want to learn about MTHFR—is a powerful risk for Alzheimer's" (said at 0:58:07)

Characterizing MTHFR variants as a 'powerful risk' for Alzheimer's disease is overstated. Meta-analyses of observational case-control studies indicate that while the MTHFR C677T variant is associated with a modest increase in risk (odds ratios typically ranging between 1.13 and 1.31), the effect is minor compared to major genetic risk factors such as APOE ε4 and is inconsistent across populations (often restricted to Asian cohorts rather than Caucasian cohorts). Furthermore, meta-analyses for the other common variant, MTHFR A1298C, show no statistically significant association with Alzheimer's disease risk.

7

Needs context

0:15:44Sara Gottfriedneeds contextmoderate

On average, men tend to have a larger amygdala than women.

"I think about some of the imaging data again and the differences between the male and the female brain, and I know that on average men tend to have a larger amygdala." (said at 0:15:44)

In absolute (uncorrected) volume, men on average have an amygdala approximately 10% larger than women. However, meta-analytic evidence shows that this difference is fully accounted for by overall differences in total brain volume and intracranial volume (which are roughly 11% to 12% larger in men). When amygdala volume is adjusted or normalized for total brain size, the difference between sexes becomes small (<1% to 2.5%) and statistically non-significant, indicating that the amygdala is not selectively or disproportionately enlarged in men.

  • context: Meta-analysis reveals a lack of sexual dimorphism in human amygdala volume. (NeuroImage 2017) · cited 137x in the literature
    "We found that uncorrected amygdala volume is about 10% larger in males, with pooled sex difference effect sizes of g=0.581 for right amygdala (κ=28, n=2022), 0.666 for left amygdala (κ=28, n=2006), and 0.876 for bilateral amygdala (κ=16, n=1585) volumes (all p values < 0.001). However, this difference is comparable to the sex differences in intracranial volume (ICV; g=1.186, p<.001, 11.9% larger in males, κ=11) and total brain volume (TBV; g=1.278, p<0.001, 11.5% larger in males, κ=15) reported in subsets of the same studies, suggesting the sex difference in AV is a product of larger brain size in males. Among studies reporting AVs normalized for ICV or TBV, sex difference effect sizes were small and not statistically significant" (abstract, results, passage verified)
    pubmedfull study (doi)
0:19:35Sara Gottfriedneeds contextlow

Approximately 20% of women in perimenopause show no cerebral metabolic decline on brain imaging, resembling men through the same period.

"And—and what I think is exciting is that she's also found that 20% of women in perimenopause have no change at all. They look more like men who have no change through the same time period." (said at 0:19:35)

Published multimodality brain imaging studies by Dr. Lisa Mosconi and colleagues confirm the speaker's broader point: age-matched men maintain stable cerebral glucose metabolism during midlife, whereas women undergoing the perimenopausal and postmenopausal transitions exhibit significant reductions in brain glucose metabolism (CMRglc) and mitochondrial bioenergetics on FDG-PET imaging compared to premenopausal controls and men. However, peer-reviewed publications from this cohort report group-level declines in metabolic activity (often showing an average 15–25% reduction in brain energy in affected regions), rather than establishing a specific published metric that exactly 20% of perimenopausal women experience zero metabolic change.

0:23:38David Perlmutter (host)needs contextvery low

Women diagnosed with PCOS show a 10% to 14% reduction in cerebral glucose utilization.

"and also importantly women diagnosed with PCOS, who have anywhere from a 10% to 14% percent decline in their cerebral utilization of glucose." (said at 0:23:38)

The claimed 10% to 14% reduction is drawn directly from a small pilot study (7 young, normal-weight women with PCOS and 11 controls) using 18F-FDG PET imaging. The study found a 9% to 14% reduction in the cerebral metabolic rate of glucose (CMRglu) in specific brain regions (areas of the frontal, parietal, and temporal cortices), rather than a global whole-brain reduction. Because the evidence comes from a single preliminary study with a very small sample size, broader generalization requires qualification.

0:24:48David Perlmutter (host)needs contextmoderate

Eighty percent of women with polycystic ovary syndrome (PCOS) have insulin resistance.

"80% of women with PCOS have insulin resistance and are put on metformin for that reason and others along with their obesity." (said at 0:24:48)

Estimates of insulin resistance (IR) in polycystic ovary syndrome (PCOS) generally range between 55% and 80% overall, depending on the diagnostic method and population. Gold-standard hyperinsulinemic-euglycemic clamp studies show that approximately 70% to 75% of women with PCOS have IR overall (and 80% to 94% among those with overweight or obesity, compared to 55% to 60% among lean individuals). Meta-analyses also confirm a significant intrinsic reduction in insulin sensitivity (~27%) across all PCOS phenotypes independent of BMI.

0:32:34Sara Gottfriedneeds contextlow

Only about 3% of the population does well with less than seven hours of sleep per night.

"And we also know that only about 3% of the population does well with less than seven hours of sleep." (said at 0:32:34)

Sleep medicine guidelines and epidemiological studies generally recommend at least 7 hours of sleep per night for adults, noting that genuine "natural short sleepers"—individuals who thrive, maintain normal cognitive function, and experience minimal daytime impairment on less than 7 hours of sleep without accumulating sleep debt—represent a rare segment of the general population (often estimated at around 1% to 3%). However, precise population prevalence estimates remain challenging to verify because rare Mendelian genetic variants associated with familial natural short sleep (such as mutations in BHLHE41/DEC2, ADRB1, NPSR1, and GRM1) are extremely rare and show variable penetrance in large population biobanks. Furthermore, objective laboratory studies indicate that many individuals who subjectively believe they function well on short sleep demonstrate measurable objective drowsiness and microsleeps under low-stimulation conditions.

0:40:45Sara Gottfriedneeds contextmoderate

The average American woman consumes only about 12 grams of dietary fiber per day.

"and it's sad to me to realize that on average an American woman gets about 12 grams of fiber a day." (said at 0:40:45)

The speaker is correct that American women consume substantially less dietary fiber than recommended (the adequate intake is 25–28 g/day), but the actual national average is slightly higher than 12 grams per day. Nationally representative data from the National Health and Nutrition Examination Survey (NHANES) report average daily fiber intakes among adult U.S. women between roughly 14.8 g/day and 15.4 g/day (for example, 15.4 g/day in women aged 19–50 and 14.8 g/day in postmenopausal women), with subgroups such as non-Hispanic Black women averaging closer to 12–13 g/day.

0:50:15David Perlmutter (host)needs contextlow

Carriers of the APOE4 allele have a significantly greater accumulation of beta-amyloid in the brain if they are insulin resistant.

"For example, some of the stuff I presented at the conference that you and I were attending showed that while there is a significant increased risk for accumulation of beta-amyloid in your brain if you have the APOE4 allele, that risk is hugely increased carrying the amyloid in your brain if you are insulin resistant." (said at 0:50:15)

Longitudinal cohort data show that midlife insulin resistance is an independent predictor of late-life brain beta-amyloid accumulation on PET imaging (tripling the odds of amyloid positivity), but this increased risk is observed in both APOE ε4 carriers and non-carriers rather than being an effect exclusive to or synergistic with APOE4.

19

Supported by research

0:12:17David Perlmutter (host)supportedmoderate

Inadequate sleep increases cortisol levels, induces inflammation, and increases insulin resistance.

"But the inadequate sleep that we receive through upregulating cortisol and being an inflammatory event, increasing insulin resistance" (said at 0:12:17)

The host's statement that inadequate sleep upregulates cortisol, induces inflammation, and increases insulin resistance is supported by clinical and metabolic literature. Syntheses of experimental and epidemiological evidence show that sleep loss elevates cortisol levels, activates neuroendocrine and inflammatory pathways, and impairs insulin sensitivity (increasing insulin resistance). Although acute short-term sleep restriction studies in laboratory settings show varying immediate effects on specific circulating inflammatory cytokines and hypothalamic-pituitary-adrenal axis markers, the established body of evidence connects insufficient sleep to elevated cortisol, systemic inflammatory signaling, and metabolic dysfunction including insulin resistance.

0:18:11Sara Gottfriedsupportedmoderate

Perimenopause lasts on average for 2 to 8 years, typically between the ages of 35 and 51.

"she looks at perimenopause, which on average lasts for women for 2 to 8 years, typically between 35 and 51" (said at 0:18:11)

Large prospective cohort data, such as the multiethnic Study of Women's Health Across the Nation (SWAN), show that the menopausal transition (perimenopause) typically lasts around 4 to 8 years on average, with median duration ranging from approximately 4.4 to 8.6 years depending on age of onset. Perimenopause generally starts in a woman's late 30s to 40s (around ages 35–45) and concludes at natural menopause, which occurs at an average age of 51.

0:18:28Sara Gottfriedsupportedlow

Research by Lisa Mosconi shows that women begin developing cerebral glucose hypometabolism in perimenopause, preceding Alzheimer's disease diagnosis by over 25 years.

"And what she's found is that women, starting in perimenopause, have these changes in the brain that predate the diagnosis of Alzheimer's by 25-plus years. Now, much of your work is about, okay, what can we do to prevent that arc to Alzheimer's disease? And what I think is so interesting about her work is that she's seen these changes—I think of it as kind of a slowdown in metabolism of the brain, she calls it cerebral hypometabolism, meaning that glucose just isn't taken up in the same way." (said at 0:18:28)

Neuroimaging research led by Dr. Lisa Mosconi demonstrated that women transitionally develop cerebral glucose hypometabolism in Alzheimer's disease-vulnerable brain regions starting during perimenopause (typically in their 40s and 50s), several decades before the typical age of clinical Alzheimer's disease diagnosis (typically age 75+). Using 18F-FDG-PET scans, these observational studies showed that perimenopausal and postmenopausal women exhibit significant reductions in brain glucose metabolism compared to premenopausal controls and age-matched men.

0:20:43David Perlmutter (host)supportedmoderate

Research by Dr. Stephen Cunnane using C-11 acetoacetate PET shows that brain ketone utilization remains preserved in early to mild-mid stage Alzheimer's disease.

"his work looks at brain metabolism using a radioactive C-11 acetoacetate, which is a marker for the utilization of ketones. And what he has demonstrated is in individuals who do show those glucose hypometabolism or bioenergetic deficits, which we used to think was an indication of neuronal failure—that the reason the brain shows these deficits in glucose utilization is because the neurons were dying. Well, it turns out that's not true at all. That when ketones are supplied and you image the brain, it lights up in a very normal way, and that ketone utilization is preserved even in early to mild-mid stage Alzheimer's disease." (said at 0:20:43)

Dual-tracer PET imaging studies led by Dr. Stephen Cunnane using 11C-acetoacetate (a PET tracer for ketone metabolism) and 18F-FDG (for glucose metabolism) confirm that cerebral ketone uptake and utilization remain preserved in patients with mild-to-moderate Alzheimer's disease and mild cognitive impairment, despite significant regional glucose hypometabolism. When exogenous ketone supply is elevated (e.g., via ketogenic medium-chain triglyceride supplementation), brain ketone uptake increases proportionally in patients with mild-moderate Alzheimer's disease at rates comparable to healthy controls.

0:25:34David Perlmutter (host)supportedmoderate

In a one-year study by Dr. Sarah Hallberg, patients achieved restoration of insulin sensitivity, medication reduction, and discontinuation of sulfonylureas across the entire interventional group.

"You know, in a one-year study was able to show restoration of insulin sensitivity, reduction of medication, discontinuing sulfonylureas in the entire interventional group." (said at 0:25:34)

The host's claim accurately reflects the published 1-year results of an open-label, non-randomized controlled clinical trial led by Dr. Sarah Hallberg (PMID 29417495). In 262 adults with type 2 diabetes receiving a continuous care intervention with carbohydrate restriction (nutritional ketosis), 1-year results demonstrated a 55% improvement in HOMA-IR (indicating restored insulin sensitivity), a significant decrease in diabetes medications (prescription of non-metformin diabetes medications dropped from 56.9% to 29.7%), and 100% discontinuation of sulfonylurea prescriptions across the intervention group.

0:26:44Sara Gottfriedsupportedmoderate

An October 2018 study from the University of Texas demonstrated that individuals in midlife (in their 40s) in the top third of cortisol levels have brain shrinkage along with reduced memory and visual perception.

"She shared with me some data from October 2018 from the University of Texas. I'm sure you probably saw this data too, showing that in midlife, starting in your 40s in both men and women, stress has major effects on brain structure and function. So we know that women are more vulnerable than men. We know that high levels of stress, so if you take the people who have kind of the top third in terms of cortisol, the main hormone of stress, they have shrinkage of the brain. And I haven't seen a lot of data on that in women in their 40s. So I think this is really important. So it affects the structure of the brain, it reduces the volume of the brain, and it also is associated with reduced memory and visual perception." (said at 0:26:44)

A cross-sectional analysis from the Framingham Heart Study led by researchers at the University of Texas Health Science Center at San Antonio (published in Neurology in October 2018) examined 2,231 dementia-free participants with a mean age of 48.5 years. The authors found that individuals in the highest tertile of fasting morning cortisol had significantly lower total cerebral brain volume, reduced frontal and occipital gray matter volumes, and poorer performance on tests of memory and visual perception compared to those in the middle tertile. Furthermore, the inverse association between cortisol and total brain volume was statistically significant in women but not in men.

0:28:41David Perlmutter (host)supportedvery low

Low levels of cortisol are necessary for memory encoding, but high levels are toxic to the hippocampus.

"from that we learned that, yes, it is directly toxic to the hippocampus, but at very low levels cortisol actually is a virtual requirement for encoding memory." (said at 0:28:41)

Preclinical and mechanistic literature establishes an inverted-U relationship between glucocorticoids (such as cortisol and corticosterone) and hippocampal function. Basal or low glucocorticoid signaling is required for normal hippocampal synaptic plasticity and spatial memory encoding; blocking these receptors or removing adrenal steroids impairs memory. Conversely, prolonged exposure to high levels of glucocorticoids induces dendritic atrophy, neuroendangerment, and neuronal loss (neurotoxicity) specifically within the hippocampus.

0:30:27David Perlmutter (host)supportedhigh

The dentate gyrus of the hippocampus is an area of the brain capable of adult neurogenesis.

"that's the area of the brain, the dentate gyrus of the hippocampus, that regenerates. Who knew that?" (said at 0:30:27)

The statement accurately reflects established neuroscience literature. Adult neurogenesis in humans and mammalian models is well-documented to occur in specific niches of the adult brain, primarily the subgranular zone of the dentate gyrus within the hippocampus, where neural stem and progenitor cells continue to generate functional granule neurons throughout adulthood.

0:30:41David Perlmutter (host)supportedmoderate

Lowering dietary sugar and refined carbohydrate intake induces ketone production and enhances brain-derived neurotrophic factor (BDNF).

"we eat a lower-sugar or lower-refined carbohydrate diet to emphasize the production of ketones to enhance brain-derived neurotrophic factor" (said at 0:30:41)

Diets low in carbohydrates/sugars, such as ketogenic diets, shift metabolism toward ketone production (specifically β-hydroxybutyrate, β-OHB). Human randomized controlled clinical trial data show that a 3-week ketogenic diet significantly increases circulating β-OHB as well as brain-derived neurotrophic factor (BDNF) levels by 47% compared to a standard diet (PMID: 40172923). Preclinical mechanistic studies also demonstrate that β-hydroxybutyrate acts directly as an endogenous histone deacetylase (HDAC) inhibitor to induce hippocampal *BDNF* gene expression (PMID: 27253067), and systematic reviews of clinical trials confirm that ketogenic diets generally elevate BDNF levels (PMID: 41519822).

0:26:40Sara Gottfriedsupportedmoderate

Women diagnosed with polycystic ovary syndrome (PCOS) exhibit an altered gut microbiome and disrupted gut-brain axis compared to healthy controls.

"We know that women with PCOS have an altered microbiome. We know that gut-brain axis is not normal." (said at 0:26:40)

Multiple systematic reviews and meta-analyses of human observational studies demonstrate that women diagnosed with polycystic ovary syndrome (PCOS) exhibit significant gut microbial dysbiosis compared to healthy controls, characterized by reduced alpha diversity (e.g., lower Chao and Shannon indices) and alterations in relative bacterial abundances (PMID: 37739322, PMID: 37559119). Human clinical case-control studies and systematic reviews also confirm dysregulation of gut-brain axis mediators, including significantly lower serum levels of gut-brain signaling peptides such as ghrelin and serotonin, as well as altered gut microbiome-mediated neuroendocrine pathways (PMID: 42076786, PMID: 40967455).

0:36:15Sara Gottfriedsupportedmoderate

Gut bacterial beta-glucuronidase deconjugates estrogen metabolites, and gut dysbiosis can cause estrogen recirculation and elevated estradiol levels.

"We know that women tend to modulate estrogen levels differently than men, and much of that is governed by a certain set of bacteria. And what we're talking about here is an enzyme called beta-glucuronidase. And so the idea with estrogen as the master regulator in the female body is that you want to produce it, you want to use it, and then you want to get rid of it. You don't want it recirculating in the body over and over again like bad karma. And if you have kind of the dysbiosis, the wrong balance of microbes in your gut, you're more likely to keep recycling it and for your estradiol levels to climb, to get too high." (said at 0:36:15)

Published literature supports the role of the gut microbiome—specifically the 'estrobolome'—in estrogen metabolism and recirculation. Estrogens are conjugated in the liver (e.g., glucuronidation) and excreted via bile into the gastrointestinal tract. Bacterial enzymes, predominantly microbial β-glucuronidases (and sulfatases), deconjugate these metabolites back into free estrogens, permitting their reabsorption across the gut mucosa into the enterohepatic circulation. Alterations or shifts in the composition and enzymatic activity of the gut microbiota can increase deconjugation and reabsorption, raising systemic free estradiol levels.

0:39:35Sara Gottfriedsupportedvery low

The estrogen 4-quinone metabolic pathway is genotoxic and causes mutations and DNA damage.

"And there's even a 4-quinone pathway that is especially genotoxic, so it can cause mutations and damage to DNA." (said at 0:39:35)

Preclinical in vitro and animal studies demonstrate that metabolism of estrogens via 4-hydroxylation leads to the formation of catechol estrogen-3,4-quinones (CE-3,4-Q). These electrophilic metabolites covalently react with DNA purine bases, primarily forming depurinating adducts (4-OHE1/E2-1-N3Ade and 4-OHE1/E2-1-N7Gua). The resulting apurinic sites and redox-cycling reactive oxygen species cause DNA strand breaks, base damage, and error-prone repair mutations.

0:41:45David Perlmutter (host)supportedvery low

Paleolithic humans are estimated to have consumed up to 105 grams of dietary fiber per day.

"It's been estimated that our Paleolithic ancestors may have gotten as much as 105 grams of fiber a day." (said at 0:41:45)

Nutritional and anthropological reconstructions of ancestral diets estimate that Paleolithic humans consumed substantially higher amounts of dietary fiber than modern populations, with widely cited models (such as those by S. Boyd Eaton, Melvin Konner, and colleagues) calculating daily fiber intakes of approximately 100 to 104–105 grams per day depending on the estimated plant-to-animal subsistence ratios. Because these figures are indirect theoretical estimates based on archaeological evidence, botanical analysis, and ethnographic records of recent hunter-gatherer societies rather than direct observational measurements, the certainty of the historical intake estimates is very low.

0:42:45David Perlmutter (host)supportedlow

A JAMA study published around 2019 demonstrated that consumption of ultra-processed foods was associated with a 14% increased risk of all-cause mortality.

"I'm certainly sure you're aware of the study that came out just two weeks ago demonstrating that consumption of these ultra-processed foods was associated, in JAMA, was associated with an increased risk of all-cause mortality of 14%." (said at 0:42:45)

A 2019 observational cohort study published in JAMA Internal Medicine (Schnabel et al., 2019) evaluated 44,551 French adults from the NutriNet-Santé cohort over a median follow-up of 7.1 years. The study found that each 10% increment in the proportion of ultra-processed food consumed was associated with a 14% higher risk of all-cause mortality (adjusted hazard ratio 1.14, 95% CI 1.04–1.27, P = .008). Because this is an observational cohort design, the GRADE certainty for a direct causal relationship is low due to potential residual confounding.

0:43:35Sara Gottfriedsupportedlow

80% of Americans eat food in their car.

"I was horrified to read this statistic that 80% of Americans eat in their car." (said at 0:43:35)

Published sociological research on mobile eating patterns reports that over 80% of North Americans regularly eat in their cars, aligning with the cited statistic.

0:44:10Sara Gottfriedsupportedmoderate

Perceptions of social isolation, rejection, or conflict trigger the immune system to ramp up inflammation even in the absence of actual physical injury.

"what happens with the way our DNA evolved is that if you have this perception of social isolation, social rejection, or social conflict, it cues the immune system to prepare for physical injury, meaning that it ramps up and becomes inflamed even in the absence of any sort of physical injury actually occurring." (said at 0:44:10)

Published research in human social genomics confirms that perceived social isolation, rejection, and social threat activate a conserved transcriptional response to adversity (CTRA) in leukocytes. This pattern involves the up-regulation of pro-inflammatory gene expression and the down-regulation of type I interferon and antibody-related genes via sympathetic nervous system signaling, even without physical injury or acute microbial infection. Evolutionary models and empirical human and non-human primate studies demonstrate that the nervous system interprets social threat as a cue to bias immune transcription toward wound healing and antibacterial inflammatory pathways.

  • supports: Human social genomics. (PLoS genetics 2014) · cited 423x in the literature
    "In leukocytes, diverse types of social adversity evoke a common conserved transcriptional response to adversity (CTRA) characterized by increased expression of proinflammatory genes and decreased expression of genes involved in innate antiviral responses and antibody synthesis. Mechanistic analyses have mapped the neural "social signal transduction" pathways that stimulate CTRA gene expression in response to social threat and may contribute to social gradients in health." (abstract, results, passage verified)
    pubmedfull study (doi)
  • supports: Myeloid differentiation architecture of leukocyte transcriptome dynamics in perceived soci… (Proceedings of the National Academy of Sciences of the United States of America 2015) · cited 317x in the literature
    "Five longitudinal leukocyte transcriptome surveys in 141 older adults showed up-regulation of the sympathetic nervous system (SNS), monocyte population expansion, and up-regulation of the leukocyte conserved transcriptional response to adversity (CTRA). Mechanistic analyses in a macaque model of perceived social isolation confirmed CTRA activation and identified selective up-regulation of the CD14(++)/CD16(-) classical monocyte transcriptome, functional glucocorticoid desensitization, down-regulation of Type I and II interferons, and impaired response to infection by simian immunodeficiency virus (SIV)." (abstract, results, passage verified)
    pubmedfull study (doi)
0:48:25David Perlmutter (host)supportedhigh

Carrying one APOE4 allele increases the risk of developing Alzheimer's disease up to fivefold, and carrying two alleles increases the risk twelvefold.

"For example, the APOE4 allele is associated with as much as a fivefold increased risk without any other intervention for developing that condition. If you carry both, the risk is increased twelvefold." (said at 0:48:25)

Large-scale meta-analyses demonstrate that carrying one APOE4 allele increases the risk of developing Alzheimer's disease approximately 3- to 5-fold depending on population and ethnicity (e.g., an odds ratio of 3.2 in Caucasians and 5.6 in Japanese populations relative to ε3/ε3). Carrying two copies of the APOE4 allele increases the risk approximately 12- to 15-fold (odds ratio of 14.9 in Caucasians, 95% CI 10.8–20.6). The host's statement accurately reflects these established epidemiological risk estimates.

  • supports: Effects of age, sex, and ethnicity on the association between apolipoprotein E genotype an… (JAMA ) · cited 4676x in the literature
    "Among Caucasian subjects from clinic- or autopsy-based studies, the risk of AD was significantly increased for people with genotypes epsilon2/epsilon4 (OR=2.6, 95% CI=1.6-4.0), epsilon3/epsilon4 (OR=3.2, 95% CI=2.8-3.8), and epsilon4/epsilon4 (OR=14.9, 95% CI= 10.8-20.6)... The APOE epsilon4-AD association in Japanese subjects was stronger than in Caucasian subjects (epsilon3/epsilon4: OR=5.6, 95% CI=3.9-8.0; epsilon4/epsilon4: OR=33.1, 95% CI=13.6-80.5)." (abstract, results, passage verified)
    pubmed
0:49:30David Perlmutter (host)supportedhigh

Between 20% and 25% of Americans carry the APOE4 allele.

"And in the context of Alzheimer's, then if you are a carrier of the APOE4 allele, you have increased risk—we're talking 20 to 25% of Americans—then what should you do?" (said at 0:49:30)

Large epidemiological and biobank studies in the United States confirm that approximately 20% to 25% of the population carries at least one copy of the APOE-ε4 allele, although exact carrier frequencies vary somewhat by race and ethnic ancestry (e.g., ~14% in Filipino Americans to ~25% in non-Latino White Americans).

0:53:10David Perlmutter (host)supportedmoderate

Approximately 80% of autoimmune conditions occur in women.

"But the downside of unbridled inflammation, which is also affected by lifestyle choices, is increased risk for Alzheimer's and autoimmune conditions, which are, you know, 80% of which are found in women, with a few exceptions." (said at 0:53:10)

Epidemiological reviews and immunological literature widely cite that approximately 78% to 80% of individuals diagnosed with autoimmune diseases are women, although the female-to-male ratio varies considerably across specific conditions (ranging from near-equal distributions in conditions like type 1 diabetes to around 85-90% female predominance in systemic lupus erythematosus, Sjögren's syndrome, and autoimmune thyroid disease). More recent large-scale electronic health record analyses report aggregate female prevalence around 63% to 78%, confirming a strong overall female skew in autoimmune disease burden.

1

Corroborated by web sources

0:22:17David Perlmutter (host)corroborated (web)

The ketogenic diet was the most-searched health-related query on Google in 2018.

"It was the number one health-related search term on Google for 2018, and with good reason." (said at 0:22:17)

No published record matching the claim that the ketogenic diet was the number one health-related search term on Google in 2018 was located; this does not prove the claim false.

corroborated by web sources

According to Google's 2018 Year in Search data and reports from major health and news organizations, "What is the keto diet?" was the top trending health-related search question and the ketogenic diet was the most-searched diet of that year.

cbsnews.combusinessinsider.commayoclinic.org

4

No source found (not proven false)

0:09:09Sara Gottfriedunverifiedvery low

Based on structural brain imaging, sex can be classified as male or female with approximately 85% accuracy.

"if you look at a male versus female brain on imaging, you can tell with about 85% certainty that one is female, one is male." (said at 0:09:09)

No published record matching the specific claim that structural brain imaging allows male versus female classification with approximately 85% accuracy was located; this does not prove the claim false.

0:10:19Sara Gottfriedunverifiedvery low

The rates of depression, insomnia, and Alzheimer's disease are approximately double in women compared to men.

"We know that the rate of depression, the rate of insomnia, the rate of Alzheimer's disease is about double in women compared to men." (said at 0:10:19)

No published record matching the claim that the rates of depression, insomnia, and Alzheimer's disease are approximately double in women compared to men was located; this does not prove the claim false.

0:38:10Sara Gottfriedunverifiedvery low

After age 35, approximately 70% to 80% of women begin to experience wild fluctuations in estradiol production.

"And so after 35, somewhere around 70 to 80% of women start to fluctuate wildly in how much estradiol they're making, and progesterone changes as well." (said at 0:38:10)

No published record matching the claim that 70% to 80% of women begin experiencing wild fluctuations in estradiol production after age 35 was located; this does not prove the claim false. Standard reproductive aging models and longitudinal endocrine cohorts generally indicate that wide fluctuations in estradiol production are characteristic of the menopausal transition, which typically begins in the mid-to-late 40s rather than the mid-30s.

0:58:35David Perlmutter (host)unverifiedvery low

Ninety percent of vitamin D receptors in the body are represented within the brain.

"You know that 90% of the vitamin D receptors are represented within the brain, where they actually do play a role in terms of energetics." (said at 0:58:35)

No published record matching the claim that 90% of the body's vitamin D receptors are located in the brain was located; this does not prove the claim false.

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.