Gut microbiota and aging

This 2020 review explored the title subject:

“The human body contains 1013 human cells and 1014 commensal microbiota. Gut microbiota play vital roles in human development, physiology, immunity, and nutrition.

Human lifespan was thought to be determined by the combined influence of genetic, epigenetic, and environmental factors including lifestyle-associated factors such as exercise or diet. The role of symbiotic microorganisms has been ignored.

Age-associated alterations in composition, diversity, and functional features of gut microbiota are closely correlated with an age-related decline in immune system functioning (immunosenescence) and low-grade chronic inflammation (inflammaging). Immunosenescence and inflammaging do not have a unidirectional relationship. They exist in a mutually maintained state where immunosenescence is induced by inflammaging and vice versa.

Immunosenescence changes result in both quantitative and qualitative modifications of specific cellular subpopulations such as T cells, macrophages and natural killer cells as opposed to a global deterioration of the immune system. Neutrophils and macrophages from aged hosts are less active with diminished phagocytosing capability.

Gut microbiota transform environmental signals and dietary molecules into signaling metabolites to communicate with different organs and tissues in the host, mediating inflammation. Gut microbiota modulations via dietary or probiotics are useful anti-inflammaging and immunosenescence interventions.

The presence of microbiomic clocks in the human body makes noninvasive, accurate lifespan prediction possible. Prior to occurrence of aging-related diseases [shown above], bidirectional interactions between the gut and extraenteric tissue will change.

Correction of accelerated aging-associated gut dysbiosis is beneficial, suggesting a link between aging and gut microbiota that provides a rationale for microbiota-targeted interventions against age-related diseases. However, it is still unclear whether gut microbiota alterations are the cause or consequence of aging, and when and how to modulate gut microbiota to have anti-aging effects remain to be determined.”

https://www.tandfonline.com/doi/abs/10.1080/10408398.2020.1867054 “Gut microbiota and aging” (not freely available; thanks to Dr. Zongxin Ling for providing a copy)


1. The “Stable phase” predecessor to this review’s subject deserved its own paper:

“After initial exposure and critical transitional windows within 3 years after birth, it is generally agreed that human gut microbiota develops into the typical adult structure and composition that is relatively stable in adults.

gut microbiota by age phenotype

However, the Human Microbiome Project revealed that various factors such as food modernization, vaccines, antibiotics, and taking extreme hygiene measures will reduce human exposure to microbial symbionts and led to shrinkage of the core microbiome, while the reduction in microbiome biodiversity can compromise the human immune system and predispose individuals to several modern diseases.”

2. I looked for the ten germ-free references in the “How germ-free animals help elucidate the mechanisms” section of The gut microbiome: its role in brain health in this review, but didn’t find them cited. Likewise, the five germ-free references in this review weren’t cited in that paper. Good to see a variety of relevant research.

There were a few overlapping research groups with this review’s “Gut-brain axis aging” section, although it covered only AD and PD research.

3. Inflammaging is well-documented, but is chronic inflammation a condition of chronological age?

A twenty-something today who ate highly-processed food all their life could have gut microbiota roughly equivalent to their great-great grandparents’ at advanced ages. Except their ancestors’ conditions may have been byproducts of “an unintended consequence of both developmental programmes and maintenance programmes.

Would gut microbiota be a measure of such a twenty-something’s biological age? Do we wait until they’re 60, and explain their conditions by demographics? What could they do to reset themself back to a chronological-age-appropriate phenotype?


Part 2 of Switch on your Nrf2 signaling pathway

To follow up topics of Part 1‘s interview:

1. “We each have a unique microbial signature in the gut. Metabolites that you produce might not be the same ones that I produce. This makes clinical studies very difficult because you don’t have a level playing field.”

This description of inter-individual variability could inform researchers’ investigations prior to receiving experimental results such as:

Post-experimental analysis with statistical packages of these types of results is apparently required. But it doesn’t produce meaningful explanations for such individual effects.

Analysis of individual differences in metabolism can better inform explanations, because it would investigate causes for widely-variable effects. Better predictive hypotheses could be a result.

2. Today I’m starting my 40th week of eating a clinically-relevant amount of microwaved 3-day-old broccoli sprouts every day. To encourage sulforaphane’s main effect of Nrf2 signaling pathway activation, I won’t combine broccoli sprouts with anything else either during or an hour before or after.

I had been taking supplements at the same time. This interview got me thinking about the 616,645 possible combinations of my 19 supplements and broccoli sprouts.

That’s way too many to be adequately investigated by humans. Especially because contexts for each combination’s synergistic, antagonistic, or additive activities may be influenced by other combinations’ results.

I’ll just eat food and take supplements outside of this sulforaphane window. Two that I’ve started to further research because of this interview are:

A. I’ve taken 750 mg fructo-oligosaccharides (FOS) twice a day for sixteen years. I’ve considered it as my only prebiotic. Hadn’t thought of either of these points:

  • “Polyphenols are now considered to be a prebiotic food for microflora in the gut. They tend to focus on producing additional amounts of lesser known species like Akkermansia muciniphila, and have a direct prebiotic effect. Microbiota break these big, bulky molecules down into smaller metabolites, which clearly are absorbed. Some beneficial effects that come from polyphenols are not from the original molecule itself, but from a variety of metabolites produced in the gut.
  • We use a prebiotic, actually called an immunobiotic, which is a dead lactobacillus plantarum cell optimised for its cell wall content of lipoteichoic acid. Lipoteichoic acid attaches to toll-like receptor 2, and that sets off a whole host of immune-modulating processes, which tend to enhance infection control and downregulate inflammation and downregulate allergenicity.”

B. Every day I take a 400 mg capsule of 1/3, 1/6 yeast β-glucan to train my innate immune system. β-glucan also works with toll-like receptor 2, but differently than does lipoteichoic acid. Have a dozen browser tabs open on the subject.

3. “Quinone reductase is critical because it is the final enzyme in the phase two detox pathway that stops DNA being mutated or prevents deformation of DNA adducts which are mutagenic. I want to look at genes that govern redox balance, inflammation, detoxification processes, cellular energetics, and methylation.”

Gene functional group classifications are apparently required in studies, to accompany meaningless statistics. When I’ve read papers attaching significance to gene functional groups, it often seemed like hypothesis-seeking efforts to overcome limited findings.

I’ll start looking closer when study findings include Nrf2 signaling pathway targets quinone reductase, DNA damage marker 8-hydroxydeoxyguanosine, and enzymes glutathione peroxidase and glutathione S-transferase.

4. I bolded “unregulated inflammation” in Part 1 because it’s a phrase I’d ask to be defined if that site enabled comments. Thinking on inflammation seems to come from:

“We focus on the intestinal epithelial cell as a key player because if you enhance function of that cell, and Nrf2 is part of that story, once you get those cells working as they should, they are modulating this whole underlying immune network.”

An environmental signaling paradigm of aging and Reevaluate findings in another paradigm have a different focus. That paradigm looks at inflammation in the context of aging:

“A link between inflammation and aging is the finding that inflammatory and stress responses activate NF-κB in the hypothalamus and induce a signaling pathway that reduces production of gonadotropin-releasing hormone (GnRH) by neurons.

The case is particularly interesting when we realize that the aging phenotype can only be maintained by continuous activation of NF-κB. So here we have a multi-level interaction:

  1. The activation of NF-κB leads to
  2. Cellular aging, leading to
  3. A diminished production of GnRH, which then
  4. Acts (through the cells with a receptor for it, or indirectly as a result of changes to GnRH-receptor-possessing cells) to decrease lifespan.

Cell energetics is not the solution, and will never lead to a solution because it makes the assumption that cells age. Cells take on the age-phenotype the body gives them.

Aging is not a defect – it’s a programmed progressive process, a continuation of development with the body doing more to kill itself with advancing years. Progressive life-states where each succeeding life-stage has a higher mortality (there are rare exceptions).

Cellular aging is externally controlled (cell non-autonomous). None of those remedies that slow ‘cell aging’ (basically all anti-aging medicines) can significantly extend anything but old age.

For change at the epigenomic/cellular level to travel up the biological hierarchy from cells to organ systems seems to take time. But the process can be repeated indefinitely (so far as we know).”


Switch on your Nrf2 signaling pathway

An informative interview to start this year with the author of Sulforaphane: Its “Coming of Age” as a Clinically Relevant Nutraceutical in the Prevention and Treatment of Chronic Disease:

The Antioxidant Dilemma with Dr. Christine Houghton

“The thing about science is, the more you know, the more you realise you don’t know. And I have this enormous respect now for signalling processes that are going on within the cell, and not just signalling. The way mother nature switches on, switches off, foot on brake, foot on accelerator, continuously all of the time.

Things have changed in understanding the function of Nrf2 for a start, in controlling in many ways those cellular defences. We could then switch on Nrf2. You switch on a whole host of protective molecules all at the same time.

We use NAC [N-acetyl-cysteine] in the lab all the time because it stops an Nrf2 activation. So, that weak pro-oxidant signal that you use to activate Nrf2, you switch it off by giving a dose of NAC. It’s a potent antioxidant in that right, but it’s blocking signalling. And that’s what I don’t like about its broad use.

The real advantage of sulforaphane is not only is it the most potent inducer of Nrf2, or activator, but it’s also highly bioavailable. It’s a very tiny, low-molecular weight, lipophilic molecule that just glides straight in through cell membranes. It’s about 80% bioavailable. Whereas big, bulky polyphenols are about 1% bioavailable just simply because of their chemical structure.

We focus on the intestinal epithelial cell as a key player because if you enhance function of that cell, and Nrf2 is part of that story, once you get those cells working as they should, they are modulating this whole underlying immune network.

I’m particularly interested in looking at core upstream factors that govern cellular defences. So, I want to look at genes that govern redox balance, inflammation, detoxification processes, cellular energetics, and methylation.

Intestinal epithelial, just like any other cell in the body, will respond to Nrf2 activation. It will respond to NF-κB downregulation. That’s going to enhance redox control. It’s going to reduce unregulated inflammation. It’s going to enhance detoxification processes. It’ll increase glutathione synthesis.

All of those core factors that any cell needs to work normally will be enhanced by activating Nrf2. And I use a high-yielding sulforaphane supplement of about 20 milligrams a day to do that. So, that’s the beginning.

Probiotics don’t typically colonise in an adult. That’s where we come back to this idea of restoring the gut ecosystem and using prebiotic foods.

In an ideal world, we’d be looking at 600 to 800 grams of non-starchy plant foods a day. In a real world, that isn’t always going to happen.

I never use the term leaky gut because it isn’t that. It’s a dynamic structure that becomes unresponsive.”


Hadn’t thought about weighing my daily AGE-less Chicken Vegetable Soup dinner (half) then tomorrow for lunch. Its total weight tonight was 2,575.5 grams.

  • Subtract 207.2 g wine, 985.6 g chicken broth, and 64.2 g noodles;
  • Add 131 g 3-day-old broccoli sprouts microwaved to ≤ 60°C (140°F) eaten earlier;
  • Subtract an estimated 170 g (6 oz.) chicken, didn’t measure juice squeezed from one lemon, didn’t estimate evaporation from 20 minutes cooking; and
  • Didn’t include either 81 g dry weight steel-cut oats which becomes 308 g for breakfast, or 103.8 g 3-day-old hulled oat sprouts.
  • Net 1,279.5 grams non-starchy plant foods

I’m doing alright by the “600 to 800 grams of non-starchy plant foods a day” guideline. Should exercise more, though, because I eat a lot.

Topics continued in Part 2.

A broccoli sprouts study that lacked evidence for human applicability

A 2020 study Combined Broccoli Sprouts and Green Tea Polyphenols Contribute to the Prevention of Estrogen Receptor–Negative Mammary Cancer via Cell Cycle Arrest and Inducing Apoptosis in HER2/neu Mice (not freely available) conclusion was:

“Lifelong BSp [broccoli sprouts] and GTP [green tea polyphenol] administration can prevent estrogen receptor–negative mammary tumorigenesis through cell cycle arrest and inducing apoptosis in HER2/neu mice.”

These researchers had unaddressed insufficiencies in this study that were also in their 2018 study as curated below. The largest item that required translation into human applicability was rodent diet content of 26% “broccoli sprout seeds.”

You may be surprised to read the below previous study’s unevidenced advice to eat double the weight of broccoli sprouts that I eat every day. You won’t be surprised that it’s not going to happen. Especially when no alternatives were presented because rodent diet details weren’t analyzed and published.

Sulforaphane is an evolved defense mechanism to ward off predators, and eating it is evolutionarily unpleasant. Will people in general and pregnant women in particular eat a diet equivalent to 26% “broccoli sprout seeds?”

Where were peer reviewer comments and researcher responses? Are these not public as they are by all Open Access journals hosted on https://www.mdpi.com/?

Sponsors and researchers become locked into paradigms that permit human-inapplicable animal research year after year. What keeps them from developing sufficient human-applicable evidence to support their hypotheses?


This 2018 Alabama rodent study investigated the epigenetic effects on developing breast cancer of timing a sulforaphane-based broccoli sprouts diet. Timing of the diet was as follows:

  1. Conception through weaning (postnatal day 28), named the Prenatal/maternal BSp (broccoli sprouts) treatment (what the mothers ate starting when they were adults at 12 weeks until their pups were weaned; the pups were never on a broccoli sprouts diet);
  2. Postnatal day 28 through the termination of the experiment, named the Postnatal early-life BSp treatment (what the offspring ate starting at 4 weeks; the mothers were never on a broccoli sprouts diet); and
  3. Postnatal day 56 through the termination of the experiment, named the Postnatal adult BSp treatment (what the offspring ate starting when they were adults at 8 weeks; the mothers were never on a broccoli sprouts diet).

“The experiment was terminated when the mean tumor diameter in the control mice exceeded 1.0 cm.

Our study indicates a prenatal/maternal BSp dietary treatment exhibited maximal preventive effects in inhibiting breast cancer development compared to postnatal early-life and adult BSp treatments in two transgenic mouse models that can develop breast cancer.

Postnatal early-life BSp treatment starting prior to puberty onset showed protective effects in prevention of breast cancer but was not as effective as the prenatal/maternal BSp treatment. However, adulthood-administered BSp diet did not reduce mammary tumorigenesis.

The prenatal/maternal BSp diet may:

  • Primarily influence histone modification processes rather than DNA methylation processes that may contribute to its early breast cancer prevention effects;
  • Exert its transplacental breast cancer chemoprevention effects through enhanced histone acetylation activator markers due to reduced HDAC1 expression and enzymatic activity.

This may be also due to the importance of a dietary intervention window that occurs during a critical oncogenic transition period, which is in early life for these two tested transgenic mouse models. Determination of a critical oncogenic transition period could be complicated in humans, which may partially explain the controversial findings of the adult BSp treatment on breast cancer development in the tested mouse models as compared the previous studies. Thus long-term consumption of BSp diet is recommended to prevent cancers in humans.”

“The dietary concentration for BSp used in the mouse studies was 26% BSp in formulated diet, which is equivalent to 266 g (~4 cups) BSp/per day for human consumption. The concentration of BSp in this diet is physiological available and represents a practical consumption level in the human diet.

Prior to the experiment, we tested the potential influences of this prenatal/maternal BSp regimen on maternal and offspring health as well as mammary gland development in the offspring. Our results showed there was no negative effect of this dietary regimen on the above mentioned factors (data not shown) suggesting this diet is safe to use during pregnancy.”


I didn’t see where the above-labelled “Broccoli Sprout Seeds” diet content was defined. It’s one thing to state:

“SFN as the most abundant and bioactive compound in the BSp diet has been identified as a potent HDAC inhibitor that preferably influences histone acetylation processes.”

and describe how sulforaphane may do this and may do that, and include it in the study’s title. It’s another thing to quantify an animal study into findings that can help humans.

The study’s food manufacturer offers dietary products to the public without quantifying all contents. Good for them if they can stay in business by serving customers who can’t be bothered with scientific evidence.

Any difference between the above-labelled “Broccoli Sprout Seeds” and broccoli seeds? Where was any evidence that “Broccoli Sprout Seeds” and SPROUTED “Broccoli Sprout Seeds” were equivalent per this claim:

“Equivalent to 266 g (~4 cups) BSp/per day for human consumption. The concentration of BSp in this diet is physiological available and represents a practical consumption level in the human diet.”

To help humans, this animal study had to have more details than the food manufacturer provided. These researchers should have either tasked the manufacturer to specify “Broccoli Sprout Seeds” content, or contracted out analysis if they weren’t going to do it themselves.

Regarding timing of a broccoli sprouts diet for humans, this study didn’t provide evidence for recommending:

“Long-term consumption of BSp diet is recommended to prevent cancers in humans.”

http://cancerpreventionresearch.aacrjournals.org/content/early/2018/05/15/1940-6207.CAPR-17-0423.full-text.pdf “Temporal efficacy of a sulforaphane-based broccoli sprout diet in prevention of breast cancer through modulation of epigenetic mechanisms”

Part 2 of The transgenerational impact of Roundup exposure

This 2020 study followed up The transgenerational impact of Roundup exposure using the Washington State Unversity research group’s most recent methodology in DEET and permethrin cause transgenerational diseases:

“The herbicide glyphosate has been shown to promote epigenetic transgenerational inheritance of pathology and disease in subsequent great-grand offspring (F3 generation). The current study was designed to identify epigenetic biomarkers for glyphosate-induced transgenerational diseases using an epigenome-wide association study.

Pathologies investigated included prostate disease [13 of 44 subjects], kidney disease [11 of 44], obesity [19 of 45], and presence of multiple disease [10 of 45]. Sperm were collected from F3 glyphosate lineage males and used to identify specific differential DNA methylation regions (DMRs) and differential histone retention sites (DHRs).

The number of DHRs were less than the number of DMRs, and DHRs were found to have disease specificity. The combination of DMRs and DHRs is anticipated to facilitate pathology diagnosis.

Low sample number is a limitation in the current analysis. Potential higher variability in data needs to be considered.

This is one of the first observations of DHRs as potential biomarkers for disease. The current study used glyphosate induction of transgenerational disease as a proof of concept such environmental biomarkers can be identified and potentially used as diagnostics for disease susceptibility in the future.”

https://www.tandfonline.com/doi/full/10.1080/15592294.2020.1853319 “Epigenome-wide association study for glyphosate induced transgenerational sperm DNA methylation and histone retention epigenetic biomarkers for disease”


Clearing out the 2020 queue of interesting papers

I’ve partially read these 39 studies and reviews, but haven’t taken time to curate them.

Early Life

  1. Intergenerational Transmission of Cortical Sulcal Patterns from Mothers to their Children (not freely available)
  2. Differences in DNA Methylation Reprogramming Underlie the Sexual Dimorphism of Behavioral Disorder Caused by Prenatal Stress in Rats
  3. Maternal Diabetes Induces Immune Dysfunction in Autistic Offspring Through Oxidative Stress in Hematopoietic Stem Cells
  4. Maternal prenatal depression and epigenetic age deceleration: testing potentially confounding effects of prenatal stress and SSRI use
  5. Maternal trauma and fear history predict BDNF methylation and gene expression in newborns
  6. Adverse childhood experiences, posttraumatic stress, and FKBP5 methylation patterns in postpartum women and their newborn infants (not freely available)
  7. Maternal choline supplementation during the third trimester of pregnancy improves infant information processing speed: a randomized, double‐blind, controlled feeding study
  8. Preterm birth is associated with epigenetic programming of transgenerational hypertension in mice
  9. Epigenetic mechanisms activated by childhood adversity (not freely available)

Epigenetic clocks

  1. GrimAge outperforms other epigenetic clocks in the prediction of age-related clinical phenotypes and all-cause mortality (not freely available)
  2. Epigenetic age is a cell‐intrinsic property in transplanted human hematopoietic cells
  3. An epigenetic clock for human skeletal muscle
  4. Immune epigenetic age in pregnancy and 1 year after birth: Associations with weight change (not freely available)
  5. Vasomotor Symptoms and Accelerated Epigenetic Aging in the Women’s Health Initiative (WHI) (not freely available)
  6. Estimating breast tissue-specific DNA methylation age using next-generation sequencing data

Epigenetics

  1. The Intersection of Epigenetics and Metabolism in Trained Immunity (not freely available)
  2. Leptin regulates exon-specific transcription of the Bdnf gene via epigenetic modifications mediated by an AKT/p300 HAT cascade
  3. Transcriptional Regulation of Inflammasomes
  4. Adipose-derived mesenchymal stem cells protect against CMS-induced depression-like behaviors in mice via regulating the Nrf2/HO-1 and TLR4/NF-κB signaling pathways
  5. Serotonin Modulates AhR Activation by Interfering with CYP1A1-Mediated Clearance of AhR Ligands
  6. Repeated stress exposure in mid-adolescence attenuates behavioral, noradrenergic, and epigenetic effects of trauma-like stress in early adult male rats
  7. Double-edged sword: The evolutionary consequences of the epigenetic silencing of transposable elements
  8. Blueprint of human thymopoiesis reveals molecular mechanisms of stage-specific TCR enhancer activation
  9. Statin Treatment-Induced Development of Type 2 Diabetes: From Clinical Evidence to Mechanistic Insights
  10. Rewiring of glucose metabolism defines trained immunity induced by oxidized low-density lipoprotein
  11. Chronic Mild Stress Modified Epigenetic Mechanisms Leading to Accelerated Senescence and Impaired Cognitive Performance in Mice
  12. FKBP5-associated miRNA signature as a putative biomarker for PTSD in recently traumatized individuals
  13. Metabolic and epigenetic regulation of T-cell exhaustion (not freely available)

Aging

  1. Molecular and cellular mechanisms of aging in hematopoietic stem cells and their niches
  2. Epigenetic regulation of bone remodeling by natural compounds
  3. Microglial Corpse Clearance: Lessons From Macrophages
  4. Plasma proteomic biomarker signature of age predicts health and life span
  5. Ancestral stress programs sex-specific biological aging trajectories and non-communicable disease risk

Broccoli sprouts

  1. Dietary Indole-3-Carbinol Alleviated Spleen Enlargement, Enhanced IgG Response in C3H/HeN Mice Infected with Citrobacter rodentium
  2. Effects of caffeic acid on epigenetics in the brain of rats with chronic unpredictable mild stress
  3. Effects of sulforaphane in the central nervous system
  4. Thiol antioxidant thioredoxin reductase: A prospective biochemical crossroads between anticancer and antiparasitic treatments of the modern era (not freely available)
  5. Quantification of dicarbonyl compounds in commonly consumed foods and drinks; presentation of a food composition database for dicarbonyls (not freely available)
  6. Sulforaphane Reverses the Amyloid-β Oligomers Induced Depressive-Like Behavior (not freely available)

Eat broccoli sprouts for your eyes

This 2020 review subject concerned a leading cause of blindness:

“Advanced glycation end products (AGEs) are toxic compounds that have adverse effects on many tissues including the retina and lens. AGEs promote the formation of reactive oxygen species (ROS), which, in turn, boost the production of AGEs, a vicious cycle.

Diabetic retinopathy (DR) is a devastating microvascular complication of diabetes mellitus and the leading cause of blindness in working-age adults. The onset and development of DR is multifactorial. Lowering AGEs accumulation may represent a potential therapeutic approach.

Once AGEs are formed, most are irreversible. Cataracts are perhaps the earliest pathobiology of AGEs:

Nε-(carboxymethyl)-lysine (CML) [a representative AGE] in lens crystallins from diabetic (■) and non-diabetic (♦) subjects as a function of age.

The glyoxalase system is a protective mechanism that slows down synthesis of AGEs by limiting reactive dicarbonyls formed during sugar metabolism. Glutathione (GSH) in the eye is present at concentrations many times blood levels, and is a critical component of the glyoxalase system.

Proteomic analysis identified GLO1 [glyoxalase 1] as a protein differentially expressed in cells treated with sulforaphane. Sulforaphane inhibited AGEs-derived pericyte damage and delayed diabetes-induced retinal photoreceptor cell degeneration.

No AGE inhibitors have reached clinical use. The glyoxalase system and discovery of compounds that enhance this detoxifying activity represent a therapeutic alternative to fight glycation-derived damage.”

https://www.mdpi.com/2076-3921/9/11/1062/htm “Glyoxalase System as a Therapeutic Target against Diabetic Retinopathy”


The above graph – plotting a cataract AGE level against chronological age – represented life stage progression without effective personal agency, without taking responsibility for your one precious life.

Citation 156 was Activation of Nrf2 attenuates carbonyl stress induced by methylglyoxal in human neuroblastoma cells: Increase in GSH levels is a critical event for the detoxification mechanism (not freely available):

“The present study focused on the methylglyoxal (MG) detoxification mechanism. MG treatment resulted in accumulation of modified proteins bearing the structure of AGEs.

This accumulation was suppressed by activation of the Nrf2 pathway prior to MG exposure via pre-treatment with an Nrf2 activator:

Although pre-treatment with the Nrf2 activator did not affect mRNA levels of GLO1, expressions of GCL and xCT mRNA, involved in GSH synthesis, were induced prior to increase in GSH levels.

These results indicated that increase in GSH levels promoted formation of the GLO1 substrate, thereby accelerating MG metabolism via the glyoxalase system and suppressing its toxicity. Promotion of GSH synthesis via the Nrf2/Keap1 pathway is important in MG detoxification.”

Continued in Part 2.


PXL_20201121_113656177

DEET and permethrin cause transgenerational diseases

This 2020 rodent study from the labs of Dr. Michael Skinner at Washington State University examined how great-grandmothers’ insect repellent exposures produced diseases in their great-grand offspring:

“Permethrin and DEET are the pesticides and insect repellent most commonly used by humans. These pesticides have been shown to promote the epigenetic transgenerational inheritance of disease in rats.

Direct exposure impacts an individual and their germ line. If germline epigenetics are modified, offspring generated with the affected germ cell can have epigenetic impacts on health and physiology.

Negative health effects of pesticides exposure do not stop with the individuals directly exposed. Epigenetic transgenerational inheritance occurs when future generations without exposure also exhibit alterations and disease. Epigenetic alterations are more common among individuals with disease than specific genetic alterations or mutations.

Pathologies examined are relevant to human populations including prostate, testis and kidney disease, as well as multiple disease incidence. No common DMR [differential DNA methylation region] among the different transgenerational disease DMR biomarkers was identified.

Observations suggest a common set of epimutations is not present between different diseases to alter general disease susceptibility. Although suggestions of such general molecular impacts for disease susceptibility may exist, the current study suggests predominately disease specific epimutations.

DMRs are present for each individual disease on all chromosomes, except the Y chromosome and mitochondrial DNA. The multiple disease signatures are present on the Y chromosome, as well as all other chromosomes. These results support the idea that transgenerational epigenetic effects of ancestral pesticides exposure are genome-wide.

The current study used an epigenome-wide association analysis to identify an epigenetic signature of transgenerational disease present in sperm. Biomarkers identified herein may potentially be used to assess paternal transmission of disease susceptibilities to future generations.”

https://ehjournal.biomedcentral.com/articles/10.1186/s12940-020-00666-y “Epigenome-wide association study for pesticide (Permethrin and DEET) induced DNA methylation epimutation biomarkers for specific transgenerational disease”


Don’t understand how studies on long-term effects of day-to-day human actions like applying insect repellent aren’t front page news. Everyone could benefit from this knowledge. When I explained this study to coworkers, they had a lot of questions and feedback.

An interesting side note was peer review exchanges. A human behavior indicator was pushback regarding repetition of key points among sections, which the researchers justified with:

“The reader does not have to skip back and forth between sections to understand the basic design and methods used.”

Behavioral aspects of epigenetic inheritance haven’t been investigated by this research group. Wouldn’t inherited conditions produce behavioral evidence of their consequences?


Sulforaphane in the Goldilocks zone

This 2020 paper reviewed hormetic effects of a broccoli sprout compound:

“Sulforaphane (SFN) induces a broad spectrum of chemoprotective effects across multiple organs that are of importance to public health and clinical medicine. This chemoprotection is dominated by hormetic dose responses that are mediated by the Nrf2/ARE pathway and its complex regulatory interactions with other factors and pathways, such as p53 and NF-κB.

The stimulatory zone for in vitro studies proved to be consistently in the 1-10 μM range. Hormetic studies of SFN strongly targeted activation of Nrf2.

Capacity to activate Nrf2 diminishes with age, and may affect capacity of SFN to effectively enhance adaptive responses.

A 4-hour exposure induced a 24 hour Nrf2-mediated increase in enzymes that reduce free-radical damage in neurons and astrocytes. Repeated 4-hour treatment for four days affected an accumulation along with a persistent protection.

In the case of continuous exposure to SFN, such as taking a daily supplement, SFN treatment did not result in an accumulation of HMOX1 [heme oxygenase (decycling) 1 gene] mRNA or protein. This suggested that HMOX1 response may experience feedback regulation, avoiding possible harmful overproduction.”

https://www.sciencedirect.com/science/article/abs/pii/S1043661820315917 “The phytoprotective agent sulforaphane prevents inflammatory degenerative diseases and age-related pathologies via Nrf2-mediated hormesis” (not freely available)


One coauthor has been on a crusade to persuade everybody of this paradigm. Hormesis’ hypothesis isn’t falsifiable in all circumstances, however.

Hormetic effects may be experimental considerations. But what’s the point of performing sulforaphane dose-response experiments in contexts that are physiologically unachievable with humans? Two examples:

  1. Autism biomarkers and sulforaphane:

    “There was no concentration-dependence in the induction of any of the genes examined, with the higher (5 μM) concentration of SF even showing a slightly diminished effect for the induction of AKR1C1 and NQO1. Although this concentration is achievable in vivo, more typical peak concentrations of SF (and its metabolites) in human plasma are 1-2 μM.”

  2. Human relevance of rodent sulforaphane studies:

    “Over two-thirds of the animal studies have used doses that exceed the highest (and bordering on intolerable) doses of sulforaphane used in humans. The greater than 4-log spread of doses used in mice appears to be driven by needs for effect reporting in publications rather than optimization of translational science.”

This paper cited many hormetic effects that were human-irrelevant without making a distinction. It also had parts such as:

“The capacity for high concentrations of AITC [allyl isothiocyanate] to enhance genetic damage is not relevant since such high concentrations are not realistically achievable in normal human activities.

Humans ingest only the R-isomer of SFN via diet. Their dosing strategy adopted concentrations of R-SFN that were less than those employed to induce cytotoxic effects in cancer cells and that simulated its consumption as a dietary supplement.”


Landing eagle

Eat broccoli sprouts for pain?

This 2018 study investigated pain-relieving effects of two broccoli sprout compounds, sulforaphane and chlorogenic acid:

“Pharmacological evidence of the antinociceptive properties of broccoli aqueous extracts and bioactive metabolites were investigated in an experimental model of pain.

It was found that sprouts produced better antinociceptive response than seeds and inflorescence of broccoli, where SFN [sulforaphane] and CA [chlorogenic acid] were partial responsible. Opioid receptors were implicated in the antinociceptive effect of SFN, whereas calcium channels were involved in the concentration-dependent spasmolytic activity.

Our results give evidence of a dose-dependent antinociceptive effect of CA that might act in a synergic interaction with SFN and other metabolites to produce antinociceptive activity.”

https://www.sciencedirect.com/science/article/abs/pii/S0753332218333286 “Broccoli sprouts produce abdominal antinociception but not spasmolytic effects like its bioactive metabolite sulforaphane” (not freely available)


8-day-old broccoli sprouts were treated Days 5-8 with methyl jasmonate to increase glucosinolates as Our model clinical trial for Changing to a youthful phenotype with broccoli sprouts did.

I hadn’t previously noticed papers on “Chlorogenic and Sinapic acid derivatives” that are part of my daily intake, but there’s much recent research. Consider these October 2020 chlorogenic acid papers for example:


I found If it stinks, it’s good for you as a result of it citing this study. See Broccoli sprout compounds include sinapic acid derivatives to follow on that subject.

I rated this study as Required further work. This is my 31st week of eating a clinically relevant amount of broccoli sprouts every day, and I still take acetaminophen.

Epigenetic clock technology

This 2020 Norwegian study investigated current epigenetic clock technology:

“Epigenetic clocks are based on CpGs from the Illumina HumanMethylation450 BeadChip (450 K) which has been replaced by the latest platform, Illumina MethylationEPIC BeadChip (EPIC). EPIC is a major improvement over its predecessor, 450 K (> 450,000 CpGs), in terms of the number of probes (> 850,000 CpGs) and the genomic coverage of regulatory elements.

The training set of the other epigenetic clocks was mostly based on 450 K, except for the Horvath Skin & Blood clock which used both 450 K and EPIC-derived DNAm data. Additional CpGs on EPIC do not enhance the accuracy or precision of the epigenetic clocks when the training set is reduced.

We validated epigenetic clocks in EPIC-derived blood-based DNAm data (n = 470; 305 European women and 165 South Asian women). eABEC showed that the epigenetic age acceleration (EAA; residuals from the regression of DNAm age on chronological age) was higher in South Asian women than in Norwegian women.

The reason for the higher precision is likely due to the large training set (n = 2227) and the wide age-span of the samples (19 to 88 years for the training set of eABEC).

EPIC probes that are designed to cover regulatory regions did not increase precision. It is difficult to dismiss the possibility that other regulatory CpGs not currently included on EPIC might improve age prediction.”

https://bmcgenomics.biomedcentral.com/articles/10.1186/s12864-020-07168-8 “Blood-based epigenetic estimators of chronological age in human adults using DNA methylation data from the Illumina MethylationEPIC array”


The study’s main point was lacks in the current technology. The above graphic demonstrated that epigenetic clocks could do better across different ethnicities.

The study repeated a point from An epigenetic clock review by committee about increasing training set size. These researchers missed a point from Do epigenetic clocks measure causes or effects? that:

“The power of these measures as diagnostic and prognostic may stem from the use of longitudinal data in training them. Rather than continuing to train chronological age predictors using diverse data, it may be more advantageous to retrain some of the existing measures by predicting longitudinal outcomes.”

They also didn’t assign much relevance to coverage improvements of The epigenetic clock now includes skin:

“Although the skin-blood clock was derived from significantly less samples (~900) than Horvath’s clock (~8000 samples), it was found to more accurately predict chronological age, not only across fibroblasts and skin, but also across blood, buccal and saliva tissue.”


What I’d like to know about epigenetic clock measurements of biological age is: Why aren’t thousands of studies using them every year? How can we expect continuous improvements in their technologies or coverages or training sets without widespread use?

Dietary contexts matter

Two papers illustrated how actions of food compounds are affected by their contexts. The first was a 2020 UCLA rodent study:

“Long-chain polyunsaturated fatty acids (PUFAs), particularly omega-3 (n-3) PUFAs, have been indicated to play important roles in various aspects of human health. Controversies are observed in epidemiological and experimental studies regarding the benefits or lack of benefits of n-3 PUFAs.

Dietary docosahexaenoic acid (DHA; 22:6 n-3) supplementation improved select metabolic traits and brain function, and induced transcriptomic and epigenetic alterations in hypothalamic and hippocampal tissues in both context-independent and context-specific manners:

  • In terms of serum triglyceride, glycemic phenotypes, insulin resistance index, and memory retention, DHA did not affect these phenotypes significantly when examined on the chow diet background, but significantly improved these phenotypes in fructose-treated animals.
  • Genes and pathways related with tissue structure were affected by DHA regardless of the dietary context, although the direction of changes are not necessarily the same between contexts. These pathways may represent the core functions of DHA in maintaining cell membrane function and cell signaling.
  • DHA affected the mTOR signaling pathway in hippocampus. In the hypothalamus, altered pathways were more related to innate immunity, such as cytokine-cytokine receptors, NF-κB signaling pathway, and Toll-like receptor signaling pathway.

DHA exhibits differential influence on epigenetic loci, genes, pathways, and metabolic and cognitive phenotypes under different dietary contexts.”

https://onlinelibrary.wiley.com/doi/10.1002/mnfr.202000788 “Multi‐tissue Multi‐omics Nutrigenomics Indicates Context‐specific Effects of DHA on Rat Brain” (not freely available)


A human equivalent age period of the subjects was 12 to 20 years old. If these researchers want to make their study outstanding, they’ll contact their UCLA colleague Dr. Steven Horvath, and apply his new human-rat relative biological age epigenetic clock per A rejuvenation therapy and sulforaphane.

The second paper was a 2016 review Interactions between phytochemicals from fruits and vegetables: Effects on bioactivities and bioavailability (not freely available):

“The biological activities of food phytochemicals depend upon their bioaccessibility and bioavailability which can be affected by the presence of other food components including other bioactive constituents. For instance, α-tocopherol mixed with a flavonol (kaempferol or myricetin) is more effective in inhibiting lipid oxidation induced by free radicals than each component alone.

Interactions of phytochemicals may enhance or reduce the bioavailability of a given compound, depending on the facilitation/competition for cellular uptake and transportation. For example, β-carotene increases the bioavailability of lycopene in human plasma, and quercetin-3-glucoside reduces the absorption of anthocyanins.

Combinations of food extracts containing hydrophilic antioxidants and lipophilic antioxidants showed very high synergistic effects on free radical scavenging activities. A number of phytochemical mixtures and food combinations provide synergistic effects on inhibiting inflammation.

More research should be conducted to understand mechanisms of bioavailability interference considering physiological concentrations, food matrices, and food processing.”


Each of us can set appropriate contexts for our food consumption. Broccoli sprout synergies covered how I take supplements and broccoli sprouts together an hour or two before meals to keep meal contents from lowering sulforaphane bioavailability.

Combinations of my 19 supplements and broccoli sprouts are too many (616,645) for complete analyses. Just pairwise comparisons like the second paper’s example below would be 190 combinations.

binary isobologram

Contexts for each combination’s synergistic, antagonistic, or additive activities may also be influenced by other combinations’ results.

My consumption of flax oil (alpha linolenic acid C18:3) probably has effects similar to DHA since it’s an omega-3 PUFA and I take it with food. The first study’s human equivalent DHA dose was 100mg/kg, with its citation for clinical trials stating “1–9 g/day (0.45–4% of calories) n-3 PUFA.”

A 2020 review Functional Ingredients From Brassicaceae Species: Overview and Perspectives had perspectives such as:

“In many circumstances, the isolated bioactive is not as bioavailable or metabolically active as in the natural food matrix.”

It discussed categories but not combinations of phenolics, carotenoids, phytoalexins, terpenes, phytosteroids, and tocopherols, along with more well-known broccoli compounds.


Diving for breakfast

Week 28 of Changing to a youthful phenotype with broccoli sprouts

Did a little math to end this 28th week of eating a clinically relevant weight of microwaved broccoli sprouts every day:

  • I changed the title of weekly updates after Week 7 as a result of A rejuvenation therapy and sulforaphane. Numbers used from its study: “Rats were injected four times on alternate days for 8 days.”
  • Study numbers in Part 2 of Rejuvenation therapy and sulforaphane regarding the new human-rat relative biological age epigenetic clock: “The maximum lifespan for rats and humans were set to 3.8 years and 122.5 years, respectively.” I’m at a similar percentage of species maximum lifespan as were the study’s treated subjects.
  • A human-equivalent multiplication factor that can be applied to a rat post-development time period is 122.5 / 3.8 = 32.2. An 8-day rat treatment period ≈ 258 human days, and 258 / 7 ≈ 37 weeks.

To paraphrase the study’s lead laboratory researcher’s An environmental signaling paradigm of aging paper, aging is a programmed series of life stages. A body clock reset described there and subsequently experimentally tested changed 30 measurements to earlier life stages.

A reset may not require more than what I’ve been doing since the end of March. Maybe 28 weeks hasn’t been long enough to find out?


See the below discussion for a different point of view. I don’t think relative rates of metabolism between species would be more accurate than other measures because of individual differences among humans.

A chart from Microwave broccoli seeds to create sulforaphane of 10 people’s metabolisms after ingesting 200 μmol (35 mg) sulforaphane provides an example. Individual sulforaphane metabolites (DTC is dithiocarbamates) peak plasma measurements ranged from 0.359 μmol to 2.032 μmol.

sulforaphane peak plasma


So we’re patient.

Eat broccoli sprouts to pivot your internal environment’s signals

Two 2020 reviews covered some aspects of a broccoli sprouts primary action – NRF2 signaling pathway activation:

“Full understanding of the properties of drug candidates rely partly on the identification, validation, and use of biomarkers to optimize clinical applications. This review focuses on results from clinical trials with four agents known to target NRF2 signaling in preclinical studies, and evaluates the successes and limitations of biomarkers focused on:

  • Expression of NRF2 target genes [AKR1, GCL, GST, HMOX1, NQO1] and others [HDAC, HSP];
  • Inflammation [COX-2, CRP, IL-1β, IL-6, IP-10, MCP-1, MIG, NF-κB, TNF-α] and oxidative stress [8-OHdG, Cys/CySS, GSH/GSSG] biomarkers;
  • Carcinogen metabolism and adduct biomarkers in unavoidably exposed populations; and
  • Targeted and untargeted metabolomics [HDL, LDL, TG].

No biomarkers excel at defining pharmacodynamic actions in this setting.

SFN [sulforaphane] seems to affect multiple downstream pathways associated with anti-inflammatory actions. NRF2 signaling may be but one pivotal pathway.

SFN is generally considered to be the most potent natural product inducer of Nrf2 signaling. Studies in which these actions are diminished or abrogated in parallel experiments in Nrf2-disrupted mice provide the strongest lines of evidence for a key role of this transcription factor in its actions.

It is equally evident that other modes of action contribute to the molecular responses to SFN in animals and humans. Such polypharmacy may well contribute to the efficacy of the agent in disease prevention and mitigation, but obfuscates the value of specific pharmacodynamic biomarkers in the clinical development and evaluation of SFN.”

https://www.mdpi.com/2076-3921/9/8/716/htm “Current Landscape of NRF2 Biomarkers in Clinical Trials”


Why do researchers still not use epigenetic clocks in sulforaphane clinical trials? Forty mentions of disease in this review, but no consideration of aging?

This was another example of how researchers – even when stuck in a paradigm they know doesn’t sufficiently explain their area (“No biomarkers excel”) – don’t investigate other associated research areas. Why not?

Here’s what Part 2 of Rejuvenation therapy and sulforaphane had to say to those stuck on biomarkers:

“While clinical biomarkers have obvious advantages (being indicative of organ dysfunction or disease), they are neither sufficiently mechanistic nor proximal to fundamental mechanisms of aging to serve as indicators of them. It has long been recognized that epigenetic changes are one of several primary hallmarks of aging.

DNA methylation epigenetic clocks capture aspects of biological age.”


The second review Epigenetic Regulation of NRF2/KEAP1 by Phytochemicals also completely whiffed on epigenetic clocks. One mention of aging in this review, but it wasn’t of:

  • Citation 104 from Archives of Gerontology and Geriatrics; nor of
  • Citation 108 from the March 31, 2020, Aging journal; nor of
  • Citation 131 “Dietary epigenetics in cancer and aging.”

But epigenetic clock and aging associations were certainly in this review’s scope. For example, Citation 119 said:

“Nrf2 transcriptional activity declines with age, leading to age-related GSH loss among other losses associated with Nrf2-activated genes. This effect has implications, too, for decline in vascular function with age. Some of the age-related decline in function can be restored with Nrf2 activation by SFN.”

Why would people bother with phytochemicals (buzzword “compounds produced by plants”) unless to either ameliorate symptoms or address causes?

“Epigenetic Regulation of NRF2/KEAP1 by Phytochemicals” doesn’t occur in just laboratory situations. It’s also part of daily life.

These reviewers were straight-forward with side effects for two of the first review’s four items:

“The best known NRF2 activator that has obtained clinical approval is dimethyl fumarate for the treatment of multiple sclerosis. However, it has several side effects, including allergic reactions and gastrointestinal disturbance. There are a few related agents in clinical trials, such as Bardoxolone and SFX-01, a synthetic derivative of sulforaphane, which also exhibit less than desirable outcomes.”


Jet fuel exposure causes diseases in the great-grand offspring

This 2020 Washington State University rodent study examined how great-grandmothers’ JP-8 exposures produced diseases in their great-grand offspring:

“Ancestral exposure to environmental influences such as toxicants, abnormal nutrition, and traumatic stress can affect the germline epigenome and promote the epigenetic transgenerational inheritance of adult onset disease in various organisms from plants to humans. Biological mechanisms underlying transgenerational epigenetic inheritance induced by jet fuel exposure are further investigated in the current study.

Genome-wide association studies (GWAS) have found specific genetic mutations associated with human pathologies, however these genetic mutations generally appear in less than 1% of the disease population. In contrast, epimutations (DNA methylation, histone modifications, non-coding RNA, chromatin structure, and RNA methylation alterations) seem to have a higher frequency and appear in more individuals with the diseases. Determining epigenetic biomarkers for these diseases could become especially useful indicators of environmental exposures and disease susceptibility in the human population.

The number of differential methylated regions (DMRs) found in the transgenerational F3 males is between 100 and 500 for each individual pathology. Few DMRs overlap between the different pathologies which supports the possible use of epimutations as biomarkers of disease. Although further studies are required, the lack of a subpopulation of DMRs overlapping with all pathologies suggests that at a more stringent statistical threshold there are not common DMRs among specific diseases.

Although females develop transgenerational disease, insufficient numbers of oocytes can be obtained on individuals to allow epigenetic associations to be assessed. The study only examined male pathology and associated sperm epimutation associations.”

https://www.sciencedirect.com/science/article/pii/S0890623820301982 “Epigenome-wide association study for transgenerational disease sperm epimutation biomarkers following ancestral exposure to jet fuel hydrocarbons”


The only associations these study subjects had with JP-8 were their great-grandmothers’ jet fuel exposures while pregnant with their grandparents. Other environmental toxicants studied by this group that produced similar transgenerationally inherited diseases were DDT, atrazine, and vinclozolin.

Ever think about your great-grandchildren?