The Illusion of Knowledge: The paradigm shift in aging research that shows the way to human rejuvenation

Dr. Harold Katcher increased interviews to coincide with release of his book this month. Here’s one in four parts that provides highlights of his rejuvenation research progress:


Previously curated papers of his work include:

Gut microbiota and critical development periods

This 2021 rodent study focused on global histone acetylation as a model to understand roles of microbially produced short-chain fatty acids in liver function:

“Despite the utility of germ-free mice in probing complex interactions between gut microbiota and host physiology, germ-free mice are developmentally, physiologically, and metabolically unique when compared with their conventionally housed counterparts. We sought to determine whether antibiotic-mediated microbiota depletion would affect global hepatic histone acetylation states through SCFA-dependent mechanisms, as previously observed in germ-free mice.

The inability of antibiotic-mediated microbiota depletion to recapitulate findings observed in germ-free mice suggests that the transition from a germ-free to a colonized mouse leads to resilient alterations in hepatic histone acetylation states that cannot be altered by further modulating the microbial environment. This finding is distinct from other germ-free phenotypes that are considered to be partially reversible, with clear alterations in their function observed after antibiotic treatment.

histone acetylation

Comparing antibiotic-treated and untreated mice that both received CCl4 at 24 and 48 hours after injury, there were almost no histone acetylation differences. This demonstrates that hepatic injury leads to a global shift in histone acetylation that is primarily independent of gut microbiota.

Major chromatin reorganization driven by histone acetylation leads to markers of differentiation, and addition of targeted differentiation signals induces events to stabilize these histone acetylation patterns – a key feature of embryonic development and terminal cellular differentiation. Differences in histone acetylation patterns seen between germ-free and conventionally raised mice may be a developmental-like effect of hepatocytes not yet exposed to microbial by-products.

Results suggest that microbial and dietary modifications to the gut microbiome in conventionally raised mice are not a means to modulate global hepatic histone acetylation. Microbiota-dependent landscaping of the hepatic epigenome appears static in nature, while the hepatic transcriptome is responsive to alterations in the gut microbiota, yet independent of global histone acetylation.

Findings underscore significant differences between these model systems that should be taken into account when considering their relevance to human biology.”

https://aasldpubs.onlinelibrary.wiley.com/doi/10.1002/hep.32043 “Global Microbiota-Dependent Histone Acetylation Patterns Are Irreversible and Independent of Short Chain Fatty Acids” (not freely available) Thanks to Dr. Elliot S. Friedman for providing a copy.


1. By describing “a key feature of embryonic development,” this study provided a gut microbiota-liver analogy of critical periods. If developmental events don’t happen when they are required, it’s probable that their window is missed, and won’t reopen later for a second chance at normalizing.

2. Many studies used a germ-free animal model, such as:

This study provided evidence for a limitation of this model, especially when extrapolating germ-free animal results to humans without similarly testing humans.


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Natural products vs. neurodegenerative diseases

I was recently asked about taking rapamycin for its effects on mTOR. I replied that diet could do the same thing. Here’s a 2021 review outlining such effects:

“As common, progressive, and chronic causes of disability and death, neurodegenerative diseases (NDDs) significantly threaten human health, while no effective treatment is available. Recent studies have revealed the role of phosphoinositide 3-kinase (PI3K)/Akt (Protein kinase B)/mammalian target of rapamycin (mTOR) in some diseases and natural products with therapeutic potentials.

Growing evidence highlights the dysregulated PI3K/Akt/mTOR pathway and interconnected mediators in pathogenesis of NDDs. Side effects and drug-resistance of conventional neuroprotective agents urge the need for providing alternative therapies.

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Polyphenols, alkaloids, carotenoids, and terpenoids have shown to be capable of a great modulation of PI3K/Akt/mTOR in NDDs. Natural products potentially target various important oxidative/inflammatory/apoptotic/autophagic molecules/mediators, such as Bax, Bcl-2, p53, caspase-3, caspase-9, NF-κB, TNF-α, GSH, SOD, MAPK, GSK-3β, Nrf2/HO-1, JAK/STAT, CREB/BDNF, ERK1/2, and LC3 towards neuroprotection.

This is the first systematic and comprehensive review with a simultaneous focus on the critical role of PI3K/Akt/mTOR in NDDs and associated targeting by natural products.”

https://www.sciencedirect.com/science/article/abs/pii/S0944711321002075 “Natural products attenuate PI3K/Akt/mTOR signaling pathway: A promising strategy in regulating neurodegeneration” (not freely available) Thanks to Dr. Sajad Fakhri for providing a copy.


Natural products mentioned in this review that I eat in everyday foods are listed below. The most effective ones are broccoli and red cabbage sprouts, and oats and oat sprouts:

  • Artichokes – luteolin;
  • Blackberries – anthocyanins;
  • Blueberries – anthocyanins, gallic acid, pterostilbene;
  • Broccoli and red cabbage sprouts – anthocyanins, kaempferol, luteolin, quercetin, sulforaphane;
  • Carrots – carotenoids;
  • Celery – apigenin, luteolin;
  • Green tea – epigallocatechin gallate;
  • Oats and oat sprouts – avenanthramides;
  • Strawberries – anthocyanins, fisetin;
  • Tomatoes – fisetin.

Four humpback whales

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All about vasopressin

This 2021 review subject was vasopressin:

“Vasopressin is a ubiquitous molecule playing an important role in a wide range of physiological processes, thereby implicated in pathomechanisms of many disorders. The most striking is its central effect in stress-axis regulation, as well as regulating many aspects of our behavior.

Arginine-vasopressin (AVP) is a nonapeptide that is synthesized mainly in the supraoptic, paraventricular (PVN), and suprachiasmatic nucleus of the hypothalamus. AVP cell groups of hypothalamus and midbrain were found to be glutamatergic, whereas those in regions derived from cerebral nuclei were mainly GABAergic.

In the PVN, AVP can be found together with corticotropin-releasing hormone (CRH), the main hypothalamic regulator of the HPA axis. The AVPergic system participates in regulation of several physiological processes, from stress hormone release through memory formation, thermo- and pain regulation, to social behavior.

vasopressin stress axis

AVP determines behavioral responses to environmental stimuli, and participates in development of social interactions, aggression, reproduction, parental behavior, and belonging. Alterations in AVPergic tone may be implicated in pathology of stress-related disorders (anxiety and depression), Alzheimer’s, posttraumatic stress disorder, as well as schizophrenia.

An increasing body of evidence confirms epigenetic contribution to changes in AVP or AVP receptor mRNA level, not only during the early perinatal period, but also in adulthood:

  • DNA methylation is more targeted on a single gene; and it is better characterized in relation to AVP;
  • Some hint for bidirectional interaction with histone acetylation was also described; and
  • miRNAs are implicated in the hormonal, peripheral role of AVP, and less is known about their interaction regarding behavioral alteration.”

https://www.mdpi.com/1422-0067/22/17/9415/htm “Epigenetic Modulation of Vasopressin Expression in Health and Disease”


Find your way, regardless of what the herd does.

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Take taurine for your mitochondria

This 2021 review summarized taurine’s beneficial effects on mitochondrial function:

“Taurine supplementation protects against pathologies associated with mitochondrial defects, such as aging, mitochondrial diseases, metabolic syndrome, cancer, cardiovascular diseases and neurological disorders. Potential mechanisms by which taurine exerts its antioxidant activity in maintaining mitochondria health include:

  1. Conjugates with uridine on mitochondrial tRNA to form a 5-taurinomethyluridine for proper synthesis of mitochondrial proteins (mechanism 1), which regulates the stability and functionality of respiratory chain complexes;
  2. Reduces superoxide generation by enhancing the activity of intracellular antioxidants (mechanism 2);
  3. Prevents calcium overload and prevents reduction in energy production and collapse of mitochondrial membrane potential (mechanism 3);
  4. Directly scavenges HOCl to form N-chlorotaurine in inhibiting a pro-inflammatory response (mechanism 4); and
  5. Inhibits mitochondria-mediated apoptosis by preventing caspase activation or by restoring the Bax/Bcl-2 ratio and preventing Bax translocation to the mitochondria to promote apoptosis.

taurine mechanisms

An analysis on pharmacokinetics of oral supplementation (4 g) in 8 healthy adults showed a baseline taurine content in a range of 30 μmol to 60 μmol. Plasma content increased to approximately 500 μmol 1.5 h after taurine intake. Plasma content subsequently decreased to baseline level 6.5 h after intake.

We discuss antioxidant action of taurine, particularly in relation to maintenance of mitochondria function. We describe human studies on taurine supplementation in several mitochondria-associated pathologies.”

https://www.mdpi.com/1420-3049/26/16/4913/html “The Role of Taurine in Mitochondria Health: More Than Just an Antioxidant”


I take a gram of taurine at breakfast and at dinner along with other supplements and 3-day-old Avena sativa oat sprouts. Don’t think my other foods’ combined taurine contents are more than one gram, because none are found in various top ten taurine-containing food lists.

As a reminder, your mitochondria come from your mother, except in rare cases.

Preventing human infections with dietary fibers

This 2020 review covered interactions of gut microbiota, intestinal mucus, and dietary fibers. I’ve outlined its headings and subheadings, and ended with its overview:

“I. Dietary fibers and human mucus-associated polysaccharides: can we make an analogy?

I.1 Brief overview of dietary fibers and mucus polysaccharides structures and properties

I.I.1 Dietary fibers

  • Dietary fiber intake and health effects

I.I.2 Intestinal mucus polysaccharides

  • Structure
  • Main functions

I.2 Similarities and differences between dietary fibers and mucus carbohydrates

  • Origin and metabolism
  • Structure

II. Interactions of dietary fibers and mucus-associated polysaccharides with human gut microbiota

II-1 Substrate accessibility and microbial niches

  • Dietary fibers
  • Mucus polysaccharides

II-2 Recognition and binding strategies

  • Dietary fibers
  • Mucus polysaccharides

II-3 Carbohydrate metabolism by human gut microbiota

II-3.1 Specialized carbohydrate-active enzymes

II-3.2 Vertical ecological relationships in carbohydrate degradation

  • Dietary fibers
  • Mucus polysaccharides

II-3.3 Horizontal ecological relationships in carbohydrate degradation

II.4 Effect of carbohydrates on gut microbiota composition and sources of variability

II.4.1 Well-known effect of dietary fibers on the gut microbiota

II.4.2 First evidences of a link between mucus polysaccharides and gut microbiota composition

III. Gut microbiota, dietary fibers and intestinal mucus: from health to diseases?

[no III.1]

III.2 Current evidences for the relationship between dietary fibers, mucus and intestinal-inflammatory related disorder

III.2.1 Obesity and metabolic-related disorders

  • Dietary fibers
  • Mucus polysaccharides

III.2.2 Inflammatory bowel diseases

  • Dietary fibers
  • Mucus polysaccharides

III.2.3 Colorectal cancer

  • Dietary fibers
  • Mucus polysaccharides

IV. How enteric pathogens can interact with mucus and dietary fibers in a complex microbial background?

IV.1 Mucus-associated polysaccharides: from interactions with enteric pathogens to a cue for their virulence?

IV.1.1 Pathogens binding to mucus

  • Binding structures
  • Sources of variations

IV.1.2 Mucus degradation by pathogens

  • Bacterial mucinases
  • Glycosyl hydrolases

IV.1.3 Mucus-based feeding of pathogens

  • Primary degraders or cross-feeding strategies
  • Importance of microbial background

IV.1.4 Pathogens and inflammation in a mucus-altered context

IV.1.5 Modulation of virulence genes by mucus degradation products

IV.2 How can dietary fiber modulate enteric pathogen virulence?

IV.2.1 Direct antagonistic effect of dietary fibers on pathogens

  • Bacteriostatic effect
  • Inhibition of cell adhesion
  • Inhibition of toxin binding and activity

IV.2.2 Indirect effect of dietary fibers through gut microbiota modulation

  • Modulation of microbiota composition
  • Modulation of gut microbiota activity

IV.2.3 Inhibition of pathogen interactions with mucus: a new mode of dietary fibers action?

  • Binding to mucus: dietary fibers acting as a decoy
  • Inhibition of mucus degradation by dietary fibers

V. Human in vitro gut models to decipher the role of dietary fibers and mucus in enteric infections: interest and limitations?

V.1 Main scientific challenges to be addressed

V.2 In vitro human gut models as a relevant alternative to in vivo studies

V.3 In vitro gut models to decipher key roles of digestive secretions, mucus and gut microbiota

V.4 Toward an integration of host responses

V.5 From health to disease conditions

dietary fibers prevent infections

Overview of the potential role of dietary fibers in preventing enteric infections. Reliable and converging data from scientific literature are represented with numbers in circles, while data more hypothetical needing further investigations are represented with numbers in squares.

  1. Some dietary fibers exhibit direct bacteriostatic effects against pathogens.
  2. Dietary fiber degradation leads to short-chain fatty acids (SCFAs) production that can modulate pathogens’ virulence.
  3. By presenting structure similarities with receptors, some dietary fibers can prevent pathogen adhesin binding to their receptors.
  4. By the same competition mechanism, dietary fibers can also prevent toxins binding to their receptors.
  5. Dietary fibers are able to promote gut microbiota diversity.
  6. Dietary fibers may promote growth of specific strains with probiotic properties and therefore exhibit anti-infectious properties.
  7. Suitable dietary fiber intake prevents microbiota’s switch to mucus consumption, limiting subsequent commensal microbiota encroachment and associated intestinal inflammation.
  8. Dietary fibers may prevent pathogen cross-feeding on mucus by limiting mucus degradation and/or by preserving diversity of competing bacterial species.
  9. By preventing mucus over-degradation by switcher microbes, dietary fibers can hamper pathogen progression close to the epithelial brush border, and further restrict subsequent inflammation.”

https://doi.org/10.1093/femsre/fuaa052 “Tripartite relationship between gut microbiota, intestinal mucus and dietary fibers: towards preventive strategies against enteric infections” (not freely available)


There were many links among gut microbiota studies previously curated. For example, Go with the Alzheimer’s Disease evidence found:

“Akkermansia cannot always be considered a potentially beneficial bacterium. It might be harmful for the gut–brain axis in the context of AD development in the elderly.”

The current review provided possible explanations:

“Akkermansia muciniphila could be considered as a species that fulfills a keystone function in mucin degradation. It is a good example of a mucus specialist.”

Points #7-9 of the above overview inferred that insufficient dietary fiber may disproportionately increase abundance of this species. But Gut microbiota strains also found that effects may be found only below species at species’ strain levels.

These reviewers provided copies in places other than what’s linked above. Feel free to contact them for a copy.


Moon bandit

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Improving gut barriers

Three papers on gut barriers, with the first a 2020 review of four intestinal barrier layers:

“The epithelial cell layer and outer/inner mucin layer constitute the physical barrier. Intestinal alkaline phosphatase (IAP) produced by epithelial cells and antibacterial proteins secreted by Panneth cells represent the functional barrier.

Multiple layers of this barrier, from intestinal lumen to systemic circulation, include:

  1. Luminal intestinal alkaline phosphatase (IAP) that dephosphorylates bacterial endotoxin lipopolysaccharide (LPS) to detoxify it;
  2. Mucus layer that provides a physical barrier preventing interactions between gut bacteria and intestinal epithelial cells;
  3. Tight junctions between epithelial cells that limit paracellular transport of bacteria and/or bacterial products to systemic circulation; and
  4. Antibacterial proteins secreted by specialized intestinal epithelial cells or Paneth cells, and IgA [immunoglobulin A] secreted by immune cells present in lamina propria underlying the epithelial cell layer.

m_bvz039f0001

The presence of LPS in systemic circulation is identified as a causal or complicating factor in diverse diseases such as:

  • Diet-induced metabolic diseases;
  • Autism;
  • Alzheimer’s disease;
  • Parkinson’s disease;
  • Arthritis;
  • Obesity-induced osteoarthritis;
  • Asthma; and
  • Several autoimmune diseases.

Causal relationships between circulating LPS levels and development of multiple diseases underscore the importance of changes in intestinal barrier layers associated with disease development.

Correcting intestinal barrier dysfunction to modulate multiple diseases can be envisioned as a viable therapeutic option. Identifying precise defects by use of specific biomarkers would facilitate targeted interventions.”

https://academic.oup.com/jes/article/4/2/bvz039/5741771 “Intestinal Barrier Dysfunction, LPS Translocation, and Disease Development”


A second 2020 review focused on IAP:

“IAP plays a vital role in intestinal barrier function, affecting bicarbonate secretion, duodenal surface pH, nutrient resorption, local intestinal inflammation, and gut microbiota. Disturbances of IAP functions are associated with persistent inflammatory diseases associated with aging (i.e.,inflammageing), inflammatory bowel diseases, type 2 diabetes mellitus, obesity, metabolic syndrome, and chronic kidney disease (CKD).

Expression and activity of IAP are directly affected by food intake, i.e., quantity and type of macro- and micronutrients including vitamins and other bioactive nutrients, or by absence of food, as well as indirectly by composition of gut microbiota that in turn are highly dependent on food intake. Increased IAP gene expression and activity promoting detoxification of LPS may lead to improvement of both intestinal and systemic inflammation, reduced bacteria translocation, and maintaining gut barrier function.

IAP could be used as an inflammatory marker together with other markers, such as interleukins, to predict inflammation and diseases that are based on chronic inflammatory processes.”

https://doi.org/10.1007/s13167-020-00228-9 “Intestinal alkaline phosphatase modulation by food components: predictive, preventive, and personalized strategies for novel treatment options in chronic kidney disease” (not freely available)


A third paper was a 2021 rodent study by coauthors of the first paper:

“We developed intestine-specific IAP transgenic mice (IAPTg) overexpressing human chimeric IAP to examine direct effects of increased IAP expression on barrier function and development of metabolic diseases. We evaluated effects of intestine-specific IAP overexpression in hyperlipidemic Ldlr−/− mice. The data presented demonstrated significant attenuation of Western-type diet (WD)-induced LPS translocation in Ldlr−/−IAPTg mice, with significant reduction in intestinal lipid absorption, hyperlipidemia, hepatic lipids, and development of atherosclerotic lesions.

circresaha.120.317144.fig09

IAP is produced by enterocytes, and catalyzes removal of 1 of the 2 phosphate groups from the toxic lipid A moiety of LPS. This produces monophosphoryl-LPS, and results in attenuation of the downstream TLR (Toll-like receptor)-4–dependent inflammatory cascade.

IAP also:

  • Dephosphorylates other proinflammatory molecules such as flagellin and ATP, resulting in their detoxification;
  • Regulates expression of key gap junction proteins (zonula occludens, claudin, and occludin) and their cellular localization, which directly modulates intestinal barrier function;
  • Promotes growth of various commensal bacteria in the gut by decreasing luminal concentrations of nucleotide triphosphates via dephosphorylation; and
  • Translocates from the apical surface of enterocytes during fat absorption. Increased serum IAP accompanies fat absorption, which is consistent with observed increased levels of circulating LPS in WD-fed mice, providing one more likely mechanism by which WD affects intestinal barrier function via IAP.

Nutrients and food components/supplements that increase IAP include galacto- or chito- oligosaccharides, glucomannan, and vitamin D3. These provide a novel opportunity to develop simple strategies for modulation of diet/nutrition to target metabolic diseases including diabetes, fatty liver disease, atherosclerosis, and heart disease.”

https://www.ahajournals.org/doi/10.1161/CIRCRESAHA.120.317144 “Over-Expression of Intestinal Alkaline Phosphatase Attenuates Atherosclerosis”


Previously curated IAP studies were:

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Gut and brain health

This 2021 human review subject was interactions of gut health and disease with brain health and disease:

“Actions of microbial metabolites are key for appropriate gut-brain communication in humans. Among these metabolites, short-chain fatty acids (SCFAs), tryptophan, and bile acid metabolites / pathways show strong preclinical evidence for involvement in various aspects of brain function and behaviour.

Dietary fibres, proteins, and fats ingested by the host contain components which are metabolized by microbiota. SCFAs are produced from fermentation of fibres, and tryptophan-kynurenine (TRP-KYN) metabolites from dietary proteins. Primary bile acids derived from liver metabolism aid in lipid digestion, but can be deconjugated and bio-transformed into secondary bile acids.

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One of the greatest challenges with human microbiota studies is making inferences about composition of colonic microbiota from faeces. There are known differences between faecal and caecal microbiota composition in humans along with spatial variation across the gastrointestinal tract.

It is difficult to interpret microbiome-host associations without identifying the driving influence in such an interaction. Large cohort studies may require thousands of participants on order to reach 20 % explanatory power for a certain host-trait with specific microbiota-associated metrics (Shannon diversity, relative microbial abundance). Collection of metadata is important to allow for a better comparison between studies, and to identify differentially abundant microbes arising from confounding variables.”

https://www.sciencedirect.com/science/article/pii/S0149763421001032 “Mining Microbes for Mental Health: Determining the Role of Microbial Metabolic Pathways in Human Brain Health and Disease”


Don’t understand why these researchers handcuffed themselves by only using PubMed searches. For example, two papers were cited for:

“Conjugated and unconjugated bile acids, as well as taurine or glycine alone, are potential neuroactive ligands in humans.”

Compare scientific coverage of PubMed with Scopus:

  • 2017 paper: PubMed citations 39; Scopus citations 69.
  • 2019 paper: PubMed citations 69; Scopus citations 102.

Large numbers of papers intentionally missing from PubMed probably influenced this review’s findings, such as:

  1. “There are too few fibromyalgia and migraine microbiome-related studies to make definitive conclusions. However, one fibromyalgia study found altered microbial species associated with SCFA and tryptophan metabolism, as well as changes in serum levels of SCFAs. Similarly, the sole migraine-microbiota study reported an increased abundance of the kynurenine synthesis GBM (gut-brain module).
  2. Due to heterogeneity of stroke and vascular disease conditions, it is difficult to make substantial comparisons between studies. There is convincing evidence for involvement of specific microbial genera / species and a neurovascular condition in humans. However, taxa were linked to LPS biosynthesis rather than SCFA production.
  3. Several studies suggest lasting microbial changes in response to prenatal or postnatal stress, though these do not provide evidence for involvement of SCFA, tryptophan, or bile-acid modifying bacteria. Similar to stress, there are very few studies assessing impact of post-traumatic stress disorder on microbiota.”

These researchers took on a difficult task. Their study design could have been better.


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Wildlife

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Take acetyl-L-carnitine for early-life trauma

This 2021 rodent study traumatized female mice during their last 20% of pregnancy, with effects that included:

  • Prenatally stressed pups raised by stressed mothers had normal cognitive function, but depressive-like behavior and social impairment;
  • Prenatally stressed pups raised by control mothers did not reverse behavioral deficits; and
  • Control pups raised by stressed mothers displayed prenatally stressed pups’ behavioral phenotypes.

Acetyl-L-carnitine (ALCAR) protected against and reversed depressive-like behavior induced by prenatal trauma:

alcar regime

ALCAR was supplemented in drinking water of s → S mice either from weaning to adulthood (3–8 weeks), or for one week in adulthood (7–8 weeks). ALCAR supplementation from weaning rendered s → S mice resistant to developing depressive-like behavior.

ALCAR supplementation for 1 week during adulthood rescued depressive-like behavior. One week after ALCAR cessation, however, the anti-depressant effect of ALCAR was diminished.

Intergenerational trauma induces social deficits and depressive-like behavior through divergent and convergent mechanisms of both in utero and early-life parenting environments:

  • We establish 2-HG [2-hydroxyglutaric acid, a hypoxia and mitochondrial dysfunction marker, and an epigenetic modifier] as an early predictive biomarker for trauma-induced behavioral deficits; and
  • Demonstrate that early pharmacological correction of mitochondria metabolism dysfunction by ALCAR can permanently reverse behavioral deficits.”

https://www.nature.com/articles/s42003-021-02255-2 “Intergenerational trauma transmission is associated with brain metabotranscriptome remodeling and mitochondrial dysfunction”


Previously curated studies cited were:

This study had an effusive endorsement of acetyl-L-carnitine in its Discussion section, ending with:

“This has the potential to change lives of millions of people who suffer from major depression or have risk of developing this disabling disorder, particularly those in which depression arose from prenatal traumatic stress.”

I take a gram daily. Don’t know about prenatal trauma, but I’m certain what happened during my early childhood.

I asked both these researchers and those of Reference 70 for their estimates of a human equivalent to “0.3% ALCAR in drinking water.” Will update with their replies.


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Cow milk causes disease

This 2021 review followed up Epigenetic effects of cow’s milk and many papers since then:

“Epidemiological studies associate intake of cow milk with an increased risk of diseases, which are associated with overactivated mechanistic target of rapamycin complex 1 (mTORC1) signaling. Milk’s physiological function to maintain high mTORC1 signaling at the beginning of mammalian life turns into adverse health effects when this postnatal endocrine and epigenetic system is not discontinued as designated by physiological processing of the lactation genome.

Milk is a signaling interface between the maternal lactation genome and the infant’s cellular mTORC1 system that orchestrates growth, anabolism, metabolic, immunological, and neurological programming. Pasteurization combined with refrigeration exposed human milk consumers to bioactive milk exosome (MEX)-derived micro-ribonucleic acids (miRs), augmenting milk’s mTORC1 activity compared to boiled, ultra-heat-treated, or fermented milk.

milk-mediated mTORC1 signaling

Milk consumption activates five major pathways stimulating mTORC1 via:

  1. Growth factors, including growth hormone, insulin, and insulin-like growth factor 1;
  2. Amino acids, especially branched-chain amino acids;
  3. Milk fat-derived palmitic acid;
  4. Milk sugar lactose; and
  5. Epigenetic modifiers, especially MEX-derived miRs.

Understanding milk’s interaction with the central hub of metabolic regulation, mTORC1, will open new avenues for prevention of common diseases.”

https://www.mdpi.com/2218-273X/11/3/404/htm “Lifetime Impact of Cow’s Milk on Overactivation of mTORC1: From Fetal to Childhood Overgrowth, Acne, Diabetes, Cancers, and Neurodegeneration”


This reviewer is somewhat of a zealot. Still, he cited 555 references.

His genotype may tolerate lactose, but he didn’t argue for it:

“After breast feeding, mucosal expression of lactase, an intestinal enzyme hydrolyzing lactose into glucose and galactose, is downregulated in all mammals with the exception of Neolithic humans, who developed LCT [lactase gene] mutations allowing persistent lactase expression.

Lactose content of milk makes up around 2–8% by weight. Lactose hydrolysis provides glucose and galactose, which both activate mTORC1:

  • During glucose abundance and glycolysis, sufficient cellular energy is produced in the form of ATP, which suppresses AMPK activity. Aldolase operates as a sensor for glucose availability that directly links glucose shortage to activation of AMPK.
  • Galactose via induction of oxidative stress activates mTORC1. Galactose-induced overactivation of mTORC1 promotes senescence of neural stem cells and aging of mesenchymal stem cells.

Lactobacilli used in food and dairy fermentation increase NRF2 activation, resulting in NRF2-induced sestrin expression, which attenuates mTORC1 activation.”

Giving children allergies with pets

This 2021 human study investigated development and persistence of allergies:

“Allergic rhinitis (AR) is a common IgE-mediated disorder involving troublesome symptoms of nasal congestion, nasal itch, sneezing, and associated eye symptoms. Like many chronic health conditions, AR stems from complex gene–environment interactions.

130 subjects with AR were recruited. Control population included 154 healthy children who underwent a regular physical examination in the same ear, nose and throat clinic as AR patients. Individuals with history of asthma or atopic dermatitis were excluded.

AR analysis

Plenty of contradictory associations exist as whether furred pet exposure (cats and dogs) may be a risk or a protective factor for AR development. Discrepancies are likely due to the ubiquitous nature of pet allergens, while pet owners are more concerned about sanitation and many other hygiene-related reasons.

Interaction of early-life pet exposure with methylation level of ADAM33 increased the risk for AR onset 1.423 times more in children. This study provides evidence that:

  • Early-life pet exposure and low methylation level of ADAM33 increase AR risk in children; and
  • The interaction between pet exposure and methylation level of ADAM33 may play an important role in development of AR.”

https://aacijournal.biomedcentral.com/articles/10.1186/s13223-021-00526-5 “Interaction between early-life pet exposure and methylation pattern of ADAM33 on allergic rhinitis among children aged 3–6 years in China”


There’s nothing children can do about who their parents were. Exposing them to pet allergens, though, may be another example of early-life experiences causing lifelong effects.

Happy Mothers Day

This 2021 rodent study investigated effects on offspring of maternal high-fat diet (HFD) during gestation and lactation, and offspring HFD during young adulthood:

“We found that gestation was the most sensitive period to induce obesity in late life, and there was no difference between sexes in chance of obesity. Furthermore, we found that lactation and administration of a HFD post‐weaning increased incidence of lipid metabolism disorders and obesity in offspring.

gestational hfd effects on offspring

There are different windows of opportunity for programming epigenetically labile genes. Some studies support the alteration of epigenetic status during development as an important cause induced adult obesity.

Gestation is considered as the most sensitive period because high DNA synthesis and DNA methylation patterns are established for normal tissue development during the embryonic period. These two programming events are the times when the epigenetic state changes most widely in the life cycle.”

https://onlinelibrary.wiley.com/doi/10.1111/jcmm.16551 “Gestational high-fat diet impaired demethylation of Pparα and induced obesity of offspring”


Hey mothers! Do what you please. But don’t turn around and deny consequences of your behavior and choices on your descendants’ physiology and behavior, and possibly those of further descendants.

Gestation, birth, infancy, and early childhood are critical periods for humans. There’s no going back to correct errors and problems.

Gut microbiota topics

Here are thirty 2019 and 2020 papers related to Switch on your Nrf2 signaling pathway topics. Started gathering research on this particular theme three months ago.

There are more researchers alive today than in the sum of all history, and they’re publishing. I can’t keep up with the torrent of interesting papers.

on

2020 A prebiotic fructo-oligosaccharide promotes tight junction assembly in intestinal epithelial cells via an AMPK-dependent pathway

2019 Polyphenols and Intestinal Permeability: Rationale and Future Perspectives

2020 Prebiotic effect of dietary polyphenols: A systematic review

2019 Protease‐activated receptor signaling in intestinal permeability regulation

2020 Intestinal vitamin D receptor signaling ameliorates dextran sulfate sodium‐induced colitis by suppressing necroptosis of intestinal epithelial cells

2019 Intestinal epithelial cells: at the interface of the microbiota and mucosal immunity

2020 The Immature Gut Barrier and Its Importance in Establishing Immunity in Newborn Mammals

2019 Prebiotics and the Modulation on the Microbiota-GALT-Brain Axis

2019 Prebiotics, Probiotics, and Bacterial Infections

2020 Vitamin D Modulates Intestinal Microbiota in Inflammatory Bowel Diseases

2020 Microbial tryptophan metabolites regulate gut barrier function via the aryl hydrocarbon receptor

2019 Involvement of Astrocytes in the Process of Metabolic Syndrome

2020 Intestinal Bacteria Maintain Adult Enteric Nervous System and Nitrergic Neurons via Toll-like Receptor 2-induced Neurogenesis in Mice (not freely available)

2019 Akkermansia muciniphila ameliorates the age-related decline in colonic mucus thickness and attenuates immune activation in accelerated aging Ercc1−/Δ7 mice

2020 Plasticity of Paneth cells and their ability to regulate intestinal stem cells

2020 Coagulopathy associated with COVID-19 – Perspectives & Preventive strategies using a biological response modifier Glucan

2020 Synergy between Cell Surface Glycosidases and Glycan-Binding Proteins Dictates the Utilization of Specific Beta(1,3)-Glucans by Human Gut Bacteroides

2020 Shaping the Innate Immune Response by Dietary Glucans: Any Role in the Control of Cancer?

2020 Systemic microbial TLR2 agonists induce neurodegeneration in Alzheimer’s disease mice

2019 Prebiotic supplementation in frail older people affects specific gut microbiota taxa but not global diversity

2020 Effectiveness of probiotics, prebiotics, and prebiotic‐like components in common functional foods

2020 Postbiotics-A Step Beyond Pre- and Probiotics

2019 Pain regulation by gut microbiota: molecular mechanisms and therapeutic potential

2020 Postbiotics: Metabolites and mechanisms involved in microbiota-host interactions

2020 Postbiotics against Pathogens Commonly Involved in Pediatric Infectious Diseases

2019 Glutamatergic Signaling Along The Microbiota-Gut-Brain Axis

2019 Lipoteichoic acid from the cell wall of a heat killed Lactobacillus paracasei D3-5 ameliorates aging-related leaky gut, inflammation and improves physical and cognitive functions: from C. elegans to mice

2020 Live and heat-killed cells of Lactobacillus plantarum Zhang-LL ease symptoms of chronic ulcerative colitis induced by dextran sulfate sodium in rats

2019 Health Benefits of Heat-Killed (Tyndallized) Probiotics: An Overview

2020 New Horizons in Microbiota and Metabolic Health Research (not freely available)

Long-lasting benefits of a common vaccine

This 2021 review subject was effects of the 100-year-old tuberculosis vaccine:

“Bacillus Calmette-Guerin (BCG) vaccine is one of the most widely used vaccines. It protects against many non-mycobacterial infections secondary to its nonspecific immune effects.

The mechanism for these effects includes modification of innate and adaptive immunity. BCG vaccine is known to not only boost immune responses to many vaccines when they are co-administered, but also decreases severity of these infections when used alone.

Alteration in innate immunity is through histone modifications and epigenetic reprogramming of monocytes to develop an inflammatory phenotype, a process called trained immunity. Memory T cells of adaptive immunity are also responsible for resistance against secondary infections after administration of BCG vaccine, a process called heterologous immunity.

The PI3K/AKT pathway, another pathway for mediating immunity, was upregulated. This was supported by recent studies demonstrating its involvement in induction of trained immunity by both BCG and β-glucan.

BCG vaccine can modify both innate and adaptive immunity, and provide immunity not only against Mycobacterium tuberculosis but also other pathogens. Heterologous immunity and trained immunity contribute to pathophysiologic mechanisms which explain how a vaccine protects against unrelated pathogens.”

https://www.amjmedsci.org/article/S0002-9629(21)00092-6/fulltext “Bacillus Calmette-Guerin Vaccine and Nonspecific Immunity”


As inferred by “induction of trained immunity by both BCG and β-glucan” many of these findings also apply to yeast cell wall β-glucan treatments. See Choosing your future with β-glucan for a representative study.