All about walnuts’ effects

Five 2022 papers focusing on walnuts, starting with a comparison of eight tree nuts:

“The aim of the present study was to examine 8 different popular nuts – pecan, pine, hazelnuts, pistachio, almonds, cashew, walnuts, and macadamia. Total content of phenolic compounds in nuts ranged from 5.9 (pistachio) to 432.9 (walnuts) mg/100 g.

Walnuts had the highest content of polymeric procyanidins, which are of great interest as important compounds in nutrition and biological activity, as they exhibit antioxidant, anti-inflammatory, antimicrobial, cardio- and neuroprotective action. Walnuts are good sources of fatty acids, especially omega-3 and omega-6.”

https://www.sciencedirect.com/science/article/pii/S2590157522002164 “Nuts as functional foods: Variation of nutritional and phytochemical profiles and their in vitro bioactive properties”


A second study compared the same eight tree nuts plus Brazil nuts and peanuts:

“The highest total content of all analyzed flavonoids was determined in walnuts (114.861 µg/g) with epicatechin the most abundant, while the lowest was in almonds (1.717 µg/g). Epicatechin has antioxidant, anti-inflammatory, antitumor, and anti-diabetic properties. Epicatechin has beneficial effects on the nervous system, enhances muscle performance, and improves cardiac function.”

https://www.mdpi.com/1420-3049/27/14/4326/htm “The Content of Phenolic Compounds and Mineral Elements in Edible Nuts”


Next, two systematic reviews and meta-analyses of human studies:

“We carried out a systematic review of cohort studies and randomized controlled trials (RCTs) investigating walnut consumption, compared with no or lower walnut consumption, including those with subjects from within the general population and those with existing health conditions, published from 2017 to 5 May 2021.

  • Evidence published since 2017 is consistent with previous research suggesting that walnut consumption improves lipid profiles and is associated with reduced CVD risk.
  • Evidence pointing to effects on blood pressure, inflammation, hemostatic markers, and glucose metabolism remains conflicting.
  • Evidence from human studies showing that walnut consumption may benefit cognitive health, which is needed to corroborate findings from animal studies, is now beginning to accumulate.”

https://academic.oup.com/nutritionreviews/advance-article/doi/10.1093/nutrit/nuac040/6651942 “Walnut consumption and health outcomes with public health relevance – a systematic review of cohort studies and randomized controlled trials published from 2017 to present”


“We aimed to perform a systematic review and meta-analysis of RCTs to thoroughly assess data concerning effects of walnut intake on selected markers of inflammation and metabolic syndrome in mature adults. Our findings showed that:

  • Walnut-enriched diets significantly decreased TG, TC, and LDL-C concentrations, while HDL-C levels were not significantly affected.
  • No significant changes were noticed on anthropometric, cardiometabolic, and glycemic indices after higher walnut consumption.
  • Inflammatory biomarkers did not record statistically significant results.”

https://www.mdpi.com/2076-3921/11/7/1412/htm “Walnut Intake Interventions Targeting Biomarkers of Metabolic Syndrome and Inflammation in Middle-Aged and Older Adults: A Systematic Review and Meta-Analysis of Randomized Controlled Trials”


Finishing with a rodent study that gave subjects diabetes with a high-fat diet, then mixed two concentrations of walnut extract in with the treatment groups’ chow:

“This study was conducted to evaluate the protective effect of Gimcheon 1ho cultivar walnut (GC) on cerebral disorder by insulin resistance, oxidative stress, and inflammation in HFD-induced diabetic disorder mice. After HFD feed was supplied for 12 weeks, samples were orally ingested for 4 weeks to GC20 and GC50 groups (20 and 50 mg/kg of body weight, respectively).

  • Administration of GC improved mitochondrial membrane potential function, and suppressed oxidative stress in the brain.
  • GC inhibited hepatic and cerebral lipid peroxidation and the formation of serum AGEs, and increased serum antioxidant activity to improve HFD-induced oxidative stress.
  • The HFD group showed significant memory impairment in behavioral tests. On the other hand, administration of GC showed improvement in spatial learning and memory function.

walnut brain effects

Based on these physiological activities, GC showed protective effects against HFD-induced diabetic dysfunctions through complex and diverse pathways.”

https://www.mdpi.com/1420-3049/27/16/5316/htm “Walnut Prevents Cognitive Impairment by Regulating the Synaptic and Mitochondrial Dysfunction via JNK Signaling and Apoptosis Pathway in High-Fat Diet-Induced C57BL/6 Mice”


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How to measure biological age?

As mentioned in Week 127, I had biological age measured earlier this month, and received five reports two days ago on Sunday. Part of the company’s process is to follow up their reports (intrinsic aging, immune aging, pace of aging, telomere length, weight loss) with a consulting session to review and interpret, which lasted an hour yesterday.

Part of our conversation revolved around comparing my measurements with other customers. These people are a different population than people usually sampled for aging and other biomarkers, because people who pay to get their biological age measured probably actionably want to improve it.

We’ll see which items I asked the consultant to pass on to the company produce responses, and which interfere with their business or they’re too busy to get back to me. I offered more than a half-dozen specifics, but held back on items I didn’t think the consultant would adequately communicate.

I didn’t argue with the consultant’s recommendations for quercetin supplementation (at 4% bioavailability?) as part of a treatment for senescence (not measured in any of the reports?). I didn’t offer to follow-up with studies demonstrating yeast cell wall β-glucan (new to the consultant) effects on immune report findings here in my 19th year of taking it every day.

I did argue with their recommendation to take DHEA-S. I changed my mind about taking it a year and a half ago ago, but left blog posts up such as Take responsibility for your one precious life – DHEA for evidence that I’m learning.

Epigenetic clocks per The epigenetic clock theory of aging generally view biological aging as “an unintended consequence of both developmental programmes and maintenance programmes, the molecular footprints of which give rise to DNAm [DNA methylation] age estimators.”

So what would be appropriate anti-aging actions for customers to take? Should customers try to emulate youthful biological markers, and supplement DHEA-S to impact serum levels of insulin-like growth factor 1?

I don’t think so. Our bodies never evolved feedback mechanisms to determine “Time to stop the growth programs, you’ve survived to reproduction age.” Older people achieving teenagers’ DHEA-S levels and activating IGF-1 pathways, pretty much guarantees further biological aging as “an unintended consequence of both developmental programmes and maintenance programmes.”


It’s too early to recommend these biological aging measurements. We’ll see where it goes.

One good thing is the company wants their customers to tell them everything about what they’re doing. I exercise at least a half hour every day, eat Avena nuda oats for breakfast and AGE-less chicken vegetable soup for dinner, and take the following:

Before breakfast
– 3-day-old microwaved broccoli / red cabbage / mustard sprouts started from 10.7 grams of seeds, with nothing else an hour before or after
– Yeast cell wall β-glucan (Glucan 300), 1500 mg, with nothing else an hour before or after

Breakfast, lunch, and dinner
– Hyaluronic acid, Nature’s Lab, 1 serving total
– Boron, Swanson Triple Boron Complex, 9 mg total

Breakfast and dinner
Acetyl-L-carnitine, 1 g total
– Balance oil, which blends linoleic acid 1400 mg with linolenic acid 350 mg, 2 times
– Betaine anhydrous, 3 g total
– Glucosamine hydroxychloride 1.5 g total, with chondroitin sulfate 1.2 g total
Taurine, 2 g total
– 3-day-old Avena sativa oat sprouts started from 20 g seeds, 2 times

Breakfast only
– Minerals and vitamins, RDA mainly, Kirkland Signature Daily Multi
– D3 25 mcg
– Calcium alpha-ketoglutarate 1 g

Lunch only
– Vitamin K2 MK-7 600 mcg

Dinner only
– D3 50 mcg
– Zinc monomethionine 30 mg with 0.3 mg copper
– Lutein 25 mg with 5 mg zeaxanthin


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Epigenetic effects of plasma concentrate

“We use data from a safety study (n = 18, mean age 74) to investigate whether human umbilical cord plasma concentrate (hereinafter Plasma Concentrate) injected weekly (1 ml intramuscular) into elderly human subjects over a 10-week period affects different biomarkers, including epigenetic age measures, standard clinical biomarkers of organ dysfunction, mitochondrial DNA copy number (mtDNA-CN), and leukocyte telomere length.

More than 20 clinical biomarkers were significantly and beneficially altered. Telomere length and mtDNA-CN were not significantly affected by treatment.

An increase in entropy means that the methylome becomes noisier. We found that entropy was significantly decreased after treatment. Decreased entropy may implicate rejuvenation of the epigenetic landscape after plasma concentrate treatments.

changes in methylation entropy

Treatment reduced DNA methylation-based GrimAge by an average of 0.82 years, suggesting a reduction in morbidity and mortality risk. By contrast, no significant results could be observed for epigenetic clocks that estimate chronological age.

Our study lends credence to the notion that there are youth-promoting factors in the secretome of umbilical cord plasma. This conclusion has also been reached by other researchers that have provided treatment with stem cells, which do not work by plasma dilution but primarily by providing humoral factors and changing the microenvironment of cells and tissues. While there may be youth-promoting microvesicles or humoral factors that are at work, we do not want to rule out the possibility that it is ‘young and undamaged’ albumin that leads to the improvements noted, especially in light of recent evidence for such a mechanism.

This first human epigenetic clock study of plasma concentrate treatments revealed age-reversal effects according to a well-established DNA methylation-based estimator of morbidity and mortality risk. Future placebo-controlled replication studies are warranted with a larger number of participants over a longer study period, which our laboratory has undertaken to pursue.”

https://onlinelibrary.wiley.com/doi/10.1111/acel.13696 “Umbilical cord plasma concentrate has beneficial effects on DNA methylation GrimAge and human clinical biomarkers”


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The goddess of rainbows

Two 2022 papers, starting with a review of irisin:

“This article is an overview of irisin generation, secretion, and tissue distribution. Its targeting of tissues or organs for prevention and treatment of chronic diseases is systematically summarized, with discussion of underlying molecular mechanisms.

Irisin is an exercise-induced myokine expressed as a bioactive peptide in multiple tissues and organs. Exercise and cold exposure are major inducers for its secretion.

Mechanistic studies confirm that irisin is closely correlated with lipid metabolism, insulin resistance, inflammation, ROS, endocrine, neurotrophic factors, cell regeneration and repairing, and central nervous system regulation. Irisin decreases with age, and is closely associated with a wide range of aging-related diseases.

A number of studies in elderly humans and animal models have shown that exercise can promote the body’s circulation and increase irisin levels in some tissues and organs. Resistance, aerobic, or combined exercise seem to play a positive role. However, exercise could not change serum irisin in some reported studies.

irisin human studies

There are large individual differences in exercise training in the elderly population. Since the half-life of irisin in the body is less than 1 h, it is necessary to pay attention to the time of blood sampling after a single exercise intervention. Some factors that impede detection of irisin levels in vivo include the half-life of irisin protein, sampling time, different tissues, and different health statuses before and after intervention.

It is worth noting that high-intensity exercise shows higher irisin levels even with the same energy expenditure during exercise. Precision studies of irisin in elderly subjects following exercise intervention need to be further clarified.”

https://www.sciencedirect.com/science/article/pii/S1568163722001222 “Irisin, An Exercise-induced Bioactive Peptide Beneficial for Health Promotion During Aging Process” (not freely available) Thanks to Dr. Ning Chen for providing a copy.


A second paper was a human study too recent to be cited by the first paper. I’ll highlight its irisin findings:

“We investigated the complex relationship among DNAm based biomarkers of aging, including DNAmFitAge, a variety of physiological functioning variables, blood serum measures including cholesterol, irisin level, and redox balance, and the microbiome on 303 healthy individuals aged between 33 and 88 years with a diverse level of physical fitness. Regular exercise was associated with younger biological age, better memory, and more protective blood serum levels.

Our research intends to show that regular physical exercise is related to microbiota and methylation differences which are both beneficial to aging and measurable. Our research provides the first investigation between microbiome derived metabolic pathways and DNAm based aging biomarkers.

Irisin levels decrease with age (0.23 average decrease for every 1 year older). We found age-related decreases in irisin levels were attenuated by exercise training. The link between irisin to GrimAge Acceleration and FitAge Acceleration is a novel observation.

HDL is positively associated with irisin. HDL and irisin have complex roles in physiology, and the positive relationship we observe between physical exercise and HDL and irisin align with protective effects seen between HDL and irisin with glucose homeostasis.

This work further supports the biological importance of irisin to the aging process. It is possible our research motivates interventions to boost irisin, like through physical exercise, as possible anti-aging therapies.”

https://www.medrxiv.org/content/10.1101/2022.07.22.22277842v1 “DNA methylation clock DNAmFitAge shows regular exercise is associated with slower aging and systemic adaptation


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Variable aging measurements

Two papers on aging measurements, starting with a 2022 human study:

“We collected longitudinally across the adult age range a comprehensive list of phenotypes within four domains (body composition, energetics, homeostatic mechanisms and neurodegeneration / neuroplasticity) and functional outcomes. We integrated individual deviations from population trajectories into a global longitudinal phenotypic metric of aging.

blsa participant ages

We demonstrate that accelerated longitudinal phenotypic aging is associated with faster physical and cognitive decline, faster accumulation of multimorbidity, and shorter survival.”

https://www.nature.com/articles/s43587-022-00243-7 “Longitudinal phenotypic aging metrics in the Baltimore Longitudinal Study of Aging”


I disagree with this study’s methodology.

1. Although it acknowledged individual variability, nothing was done to positively adjust to those facts. What could have been done per A review of biological variability was:

“Obtain a measurement of variability that is independent of the mean to ensure to not confound changes in variability with shifts in mean.”

2. A usual research practice is to take at least three measurements, and use their average as representative. That wasn’t done here, maybe because of time and expense considerations?

3. An important measurement for physical function was the time to finish a 400 meter walk. I walk more than ten times that almost every day. I use the first 400 meters as a warmup period while getting to the beach to walk eastward and enjoy the predawn light and water animal activity. I concentrate on gait speed during the last third while walking westward on a straightaway bike path.

This study would measure my gait speed as a sometimes old person during the first 400 meters, rather than a gait speed that usually approaches a young person’s during the last 400 meters. Even if I tried to walk my fastest right out of the gate, I wouldn’t be surprised to find a decade or two difference by this study’s measurements between a morning walk’s first and last 400 meter gait speeds.

4. An important cognitive function measurement was the Digital Symbol Substitution Test, apparently taken during subjects’ fasted state? Sometimes after exercising, I’m okay cognitively when starting work in a fasted state at 6:30 a.m., and other times I’m tired.

Two days ago during the last hour of work 1:30-2:30 p.m., I did outstanding work, four hours after eating whole oats for breakfast, and after drinking two coffees and three teas. I took time to put together pieces of puzzles into proper contexts for management’s attention. My bosses weren’t too pleased with the story it told, but it is what it is.

5. Are measurements of how you start what matters? Or is it how you finish, as is common in competitive sports?

This study would measure my cognitive function as a sometimes old person, rather than performance that approaches a young person’s later in the workday. For both physical and cognitive function, my abilities to ramp up and come close to young people’s capabilities are features that I work on, not random, inconvenient measurement variability.

6. Blood measurements were downgraded as having “limited coverage of the four phenotypic domains.” These were taken to fit into specific paradigms and epigenetic clocks. They predictably failed to show causality, as acknowledged with:

“Our analysis showed strong associations between global longitudinal phenotypic score and changes in physical and cognitive function. We did not have sufficient observations to fully separate these two dimensions over time, which would have strengthened the assumption of causality.”

Nowhere in this study was it hinted that all measurements were downstream effects of unmeasured causes. A follow-on study could reanalyze these subjects’ blood samples, MRI, and other measurements for originating upstream factors of signaling pathways and cascades per Signaling pathways and aging and An environmental signaling paradigm of aging.


Reference 35 of this first study was a 2021 human and rodent study that was tossed in as a limitation with:

“We might not have all of the relevant phenotypic measures (for example, more detailed immune profiles) for all participants.”

Its findings included:

“From the blood immunome of 1,001 individuals aged 8–96 years, we developed a deep-learning method based on patterns of systemic age-related inflammation. The resulting inflammatory clock of aging (iAge) tracked with multimorbidity, immunosenescence, frailty and cardiovascular aging, and is also associated with exceptional longevity in centenarians.

Canonical markers of acute infection such as IL-6 and tumor necrosis factor-α were not major contributors to iAge, indicating that, except for IL-1β, infection-driven inflammatory markers of the acute inflammatory response do not contribute to age-related chronic inflammation.

We conducted a follow-up study in an independent cohort of 97 extremely healthy adults (aged 25–90 years) matched for cardiovascular risk factors (including conserved levels of high-sensitivity C-reactive protein), selected from a total of 151 recruited participants using strict selection criteria. In this healthy cohort, inflammation markers were measured using a 48-plex cytokine panel. Only 6 circulating immune proteins were significantly correlated with age, with CXCL9 again the largest contributor to age-related inflammation.

CXCL9 is a T-cell chemoattractant induced by IFN-γ and is mostly produced by neutrophils, macrophages and endothelial cells (ECs). We find that CXCL9 is mainly produced by aged endothelium and predicts subclinical levels of cardiovascular aging in nominally healthy individuals.

We did not find any significant correlation between known disease risk factors reported in the study (BMI, smoking, dyslipidemia) and levels of CXCL9 gene or protein expression. We hypothesize that one root cause of CXCL9 overproduction is cellular aging per se, which can trigger metabolic dysfunction.

As ECs but not cardiomyocytes expressed the CXCL9 receptor, CXCR3, we hypothesize that this chemokine acts both in a paracrine fashion (when it is produced by macrophages to attract T cells to the site of injury) and in an autocrine fashion (when it is produced by the endothelium) creating a positive feedback loop. In this model, increasing doses of CXCL9 and expression of its receptor in these cells leads to cumulative deterioration of endothelial function in aging.

IFN-γ did not increase in expression in our cellular aging RNA-seq experiment, suggesting that there are triggers of CXCL9 (other than IFN-γ) that play a role in cellular senescence in the endothelium that are currently unknown. However, in our 1KIP study, IFN-γ was in fact the second-most important negative contributor to iAge, which could be explained by the cell-priming effect of cytokines, where the effect of a first cytokine alters the response to a different one.

iAge derived from immunological cytokines gives us an insight into the salient cytokines that are related to aging and disease. A notable difference compared to other clocks is that iAge is clearly actionable as shown by our experiments in CXCL9 where we can reverse aging phenotypes. More practical approaches range from altering a person’s exposomes (lifestyle) and/or the use of interventions to target CXCL9 and other biomarkers described here.

Our immune metric for human health can identify within healthy older adults with no clinical or laboratory evidence of cardiovascular disease, those at risk for early cardiovascular aging. We demonstrate that CXCL9 is a master regulator of vascular function and cellular senescence, which indicates that therapies targeting CXCL9 could be used to prevent age-related deterioration of the vascular system and other physiological systems as well.”

https://www.nature.com/articles/s43587-021-00082-y “An inflammatory aging clock (iAge) based on deep learning tracks multimorbidity, immunosenescence, frailty and cardiovascular aging”


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Reversing hair greying

I’ll highlight this 2021 human study’s findings regarding stress:

“We profiled hair pigmentation patterns (HPPs) along individual human hair shafts, producing quantifiable physical timescales of rapid greying transitions. White/grey hairs that naturally regain pigmentation across sex, ethnicities, ages, and body regions, quantitatively define reversibility of greying in humans.

A systematic survey of two-colored hairs on the scalp of a 35-year-old Caucasian male with auburn hair color over a 2-day period yielded five two-colored hair shafts (HSs) from the frontal and temporal scalp regions. Unexpectedly, all HSs exhibited reversal. HPP analysis further showed that all HSs underwent reversal of greying around the same time period.

A retrospective assessment of psychosocial stress levels using a time-anchored visual analog scale (participants rate and link specific life events with start and end dates) was then compared to HPPs. Reversal of greying for all hairs coincided closely with decline in stress and a 1-month period of lowest stress over the past year (0 on a scale of 0–10) following a 2-week vacation.

vacay

We were also able to examine a two-colored hair characterized by an unusual pattern of complete HS greying followed by rapid and complete reversal plucked from the scalp of a 30-year-old Asian female participant with black hair. HPP analysis of this HS showed a white segment representing approximately 2 cm.

Quantitative life stress assessment revealed a specific 2-month period associated with an objective life stressor (marital conflict and separation, concluded with relocation) where the participant rated her perceived stress as highest (9–10 out of 10) over the past year. The increase in stress corresponded in time with complete but reversible hair greying.

separation

We document a complete switch-on/off phenomena during a single anagen cycle. Proteomic features of hair greying directly implicate multiple metabolic pathways that are both reversible in nature and sensitive to stress-related neuroendocrine factors.

This new method to quantitatively map recent life history in HPPs provides an opportunity to longitudinally examine the influence of recent life exposures on human biology. Additional prospective studies with larger sample sizes are needed to confirm robust reproducibility and generalizability of our findings.”

https://elifesciences.org/articles/67437 “Quantitative mapping of human hair greying and reversal in relation to life stress”

CD38 and balance

I’ll highlight this 2022 review’s relationships between inflammation and cluster of differentiation 38:

“We review the nicotinamide adenine dinucleotide (NAD) catabolizing enzyme CD38, which plays critical roles in pathogenesis of diseases related to infection, inflammation, fibrosis, metabolism, and aging.

NAD is a cofactor of paramount importance for an array of cellular processes related to mitochondrial function and metabolism, redox reactions, signaling, cell division, inflammation, and DNA repair. Dysregulation of NAD is associated with multiple diseases. Since CD38 is the main NADase in mammalian tissues, its contribution to pathological processes has been explored in multiple disease models.

CD38 is upregulated in a cell-dependent manner by several stimuli in the presence of pro-inflammatory or secreted senescence factors or in response to a bacterial infection, retinoic acid, or gonadal steroids. CD38 is stimulated in a cell-specific manner by lipopolysaccharide, tumor necrosis factor alpha, interleukin-6, and interferon-γ.

dysregulated inflammation

CD38 plays a critical role in inflammation, migration, and immunometabolism, but equally important is resolution of the inflammatory response which left unchecked leads to loss of self-tolerance, tissue infiltration of lymphocytes, and circulation of autoantibodies.

  • Depending upon context, CD38 can either promote or protect against an autoimmune response.
  • Chronic mucosal inflammation and tissue damage characteristic of inflammatory bowel disease predisposes IBD patients to development of colorectal cancer, and the risks increase with duration, extent, and severity of inflammation.
  • Pulmonary fibrosis occurs in the presence of unresolved inflammation and dysregulated tissue repair, and results from an array of injurious stimuli including infection, toxicant exposure, adverse effects of drugs, and autoimmune response.
  • Modulating CD38 and NAD levels in kidney disease may provide therapeutic approaches for prevention of inflammatory conditions of the kidney.
  • Inflammation as well as evidence of senescence are present in pathophysiology of chronic liver diseases that progress to cirrhosis.
  • Inflammation-associated metabolic diseases impair vascular function. Chronic inflammation can lead to vascular senescence and dysfunction.

One cause of NAD decline during aging is due to increase of NAD breakdown in the presence of increased CD38 expression and activity on immune cells, thus linking inflammaging with tissue NAD decline. Other sources of NAD decline include increased DNA-damage requiring PARP1 activation, and decreased NAMPT levels leading to diminished NAD synthesis through the salvage pathway.

Inflammation is among the major risk factors that predispose organisms to age-associated diseases. During aging, accumulation of senescent cells creates an environment rich in proinflammatory signals, leading to ‘inflammaging.’ Metabolically active cells lose their replicative capacity by entering an irreversible quiescent state, and are considered both a cause and a consequence of inflammaging.

Recent findings uncover a major role of CD38 in inflammation and senescence, showing that age-related NAD+ decline and the sterile inflammation of aging are partially mediated by a senescence / senescence associated secretory phenotype (SASP)-induced accumulation of CD38+ inflammatory cells in tissues. Given the clear association between the phenomenon of inflammaging, senescence, and CD38, as well as the impact of CD38 on degradation of NAD and the NAD precursor NMN, future studies should focus on CD38 as a druggable target in viral illnesses.”

https://journals.physiology.org/doi/abs/10.1152/ajpcell.00451.2021 “The CD38 glycohydrolase and the NAD sink: implications for pathological conditions” (not freely available). Thanks to Dr. Julianna Zeidler for providing a copy.


We extend good-vs.-bad thinking to nature. Does that paradigm explain much, though?

All pieces of a puzzle are important. Otherwise, evolution would have eliminated what wasn’t necessary for its purposes.

Restoring balance to an earlier phenotype suits my purposes. Don’t want to eliminate inflammatory responses, but instead, calm them down so that they’re evoked appropriately.

Your lungs and Nrf2 activity

Two 2021 papers of Nrf2 activation effects on lung diseases, with the first a McGill University review:

“Oxidative stress and subsequent activation of Nrf2 have been demonstrated in many human respiratory diseases. The purpose of this review is to summarize involvement of Nrf2 and its inducers in acute respiratory distress syndrome, chronic obstructive pulmonary disease (COPD), asthma, and lung fibrosis in both human and experimental models.

fphys-12-727806-g004

These inducers have proven particularly effective at reducing severity of oxidative stress-driven lung injury in various animal models. In humans, these compounds offer promise as potential therapeutic strategies for management of respiratory pathologies associated with oxidative stress, but there is thus far little evidence of efficacy through human trials.

Perhaps, by analogy with biologics, patients with demonstrated deficient antioxidant responses to their disease should be selected for study in future clinical trials.”

https://www.frontiersin.org/articles/10.3389/fphys.2021.727806/full “Role of Nrf2 in Disease: Novel Molecular Mechanisms and Therapeutic Approaches – Pulmonary Disease/Asthma”


A second paper was a human/rodent study of COPD:

“We investigated Nrf2 expression and epigenetic regulation, and mechanisms by which the Nrf2 signaling pathway in ferroptosis is related to COPD. These findings elucidated pathways of ferroptosis in bronchial epithelial cells in COPD, and revealed Nrf2 as a potential target for COPD treatment.

COPD_A_340113_t0001

DNA hypermethylation at specific CpG sites of the Nrf2 promoter in primary epithelial cells and in clinical lung tissues is correlated with decreased Nrf2 expression, which is related to COPD occurrence and development.”

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8684379/ “Hypermethylation of the Nrf2 Promoter Induces Ferroptosis by Inhibiting the Nrf2-GPX4 Axis in COPD”


Similar to this second paper’s CpG findings, Eat broccoli sprouts for your heart found:

“Sulforaphane (SFN) reduced Ang II‐induced CpG hypermethylation and promoted Ac‐H3 [histone H3 acetylation] accumulation in the Nrf2 promoter region, accompanied by inhibition of global DNMT [DNA methyltransferase] and HDAC [histone deacetylase] activity, and a decreased protein expression of key DNMT and HDAC enzymes. Overall, DNA methylation and histone deacetylation are considered to inhibit gene transcription with a synergistic effect.

Nrf2 can also be regulated independently of Keap1. Evidence indicates that SFN may indirectly activate Nrf2 by affecting activity of several upstream kinases.”

However, this second paper didn’t measure DNMT and HDAC inhibition, although their therapeutic effects in reducing oxidative injury and inflammation may have been present.

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Immune system aging

This 2021 review by three coauthors of Take responsibility for your one precious life – Trained innate immunity cast a wide net:

“Non-specific innate and antigen-specific adaptive immunological memories are vital evolutionary adaptations that confer long-lasting protection against a wide range of pathogens. However, these mechanisms of memory generation and maintenance are compromised as organisms age.

This review discusses how immune function regulates and is regulated by epigenetics, metabolic processes, gut microbiota, and the central nervous system throughout life. We aimed to present a comprehensive view of the aging immune system and its consequences, especially in terms of immunological memory.

aging immune system

A comprehensive strategy is essential for human beings striving to lead long lives with healthy guts, functional brains, and free of severe infections.”

https://link.springer.com/article/10.1007/s12016-021-08905-x “Immune Memory in Aging: a Wide Perspective Covering Microbiota, Brain, Metabolism, and Epigenetics”


Attempts to cover a wide range of topics well are usually uneven. For example, older information in the DNA Methylation In Adaptive Immunity section was followed by a more recent Histone Modifications in Adaptive Immunity section.

This group specializes in tuberculosis vaccine trained immunity studies, and much of what they presented also applied to β-glucan trained immunity. A dozen previously curated papers were cited.

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Epigenetic clocks so far in 2021

2021’s busiest researcher took time out this month to update progress on epigenetic clocks:

Hallmarks of aging aren’t all associated with epigenetic aging.

epigenetic aging vs. hallmarks of aging

Interventions that increase cellular lifespan aren’t all associated with epigenetic aging.

epigenetic aging vs. cellular lifespan

Many of his authored or coauthored 2021 papers developed human / mammalian species relative-age epigenetic clocks.

epigenetic clock mammalian maximum lifespan

Relative-age epigenetic clocks better predict human results from animal testing.

pan-mammalian epigenetic clock


Previously curated papers that were mentioned or relevant included:

Your pet’s biological age

This 2021 cat study developed human-comparable epigenetic clocks:

We aimed to develop and evaluate epigenetic clocks for cats, as such biomarkers are necessary for translating promising anti-aging interventions from humans to cats and vice versa. We also provided the possibility of using epigenetic aging rate of cats to inform on feline health, for which a quantitative measure is presently unavailable. Specifically, we present here DNA methylation-based biomarkers (epigenetic clocks) of age for blood from cats.

Maximum lifespan of cats is 30 years according to the animal age data base (anAge), but most cats succumb to diseases before they are 20 years old. Age is the biggest risk factor for a vast majority of diseases in animals, and cats are no exception.

Interventions to slow aging are being sought. Ideally, testing should occur in species that are evolutionarily close to humans, similar in size, have high genetic diversity, and share the same environment as humans. It has been recognized that domestic dogs fulfill these criteria.

Investigations have yet to be extended to cats although they share similar environments and living conditions with their human owners. Identification of environmental factors and living conditions that affect aging, as well as potential mitigation measures, can be achieved by proxy with cats.

The human-cat clock for relative age exhibited high correlation regardless of whether analysis was applied to samples from both species or only to cat samples. This demonstrated that relative age circumvented skewing that is inherent when chronological age of species with very different lifespans is measured using a single formula.

Evidence is compelling that epigenetic age is an indicator of biological age. These results are consistent with the fact that epigenetic clocks developed for one mammalian species can be employed – to a limited extent – to other species, and reveal association of DNA methylation changes with age.

Human epigenetic age acceleration is associated with a wide array of primary traits, health states, and pathologies. While it is still unclear why age acceleration is connected to these characteristics, it does nevertheless suggest that extension of similar studies to cats may allow for development of epigenetic age acceleration as a surrogate or indicator of feline biological fitness.”

https://link.springer.com/article/10.1007%2Fs11357-021-00445-8 “Epigenetic clock and methylation studies in cats”


As noted earlier this summer in Smoke and die early, while your twin lives on, Dr. Steve Horvath is on a torrid publishing streak this year. He’s made it questionable for study designs based on published science to omit epigenetic clocks.

I titled this post Your pets because I’m too allergic to have cats, dogs, etc. live with me. Maybe this year’s focus on making my gut microbiota happy will change that?

My pets live free:

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Improving epigenetic clocks’ signal-to-noise ratio

This 2021 computational study investigated several methods of improving epigenetic clock reliability:

“Epigenetic clocks are widely used aging biomarkers calculated from DNA methylation data. Unfortunately, measurements for individual CpGs can be surprisingly unreliable due to technical noise, and this may limit the utility of epigenetic clocks.

Noise produces deviations up to 3 to 9 years between technical replicates for six major epigenetic clocks. Elimination of low-reliability CpGs does not ameliorate this issue.

We present a novel computational multi-step solution to address this noise, involving performing principal component analysis (PCA) on the CpG-level data followed by biological age prediction using principal components as input. This method extracts shared systematic variation in DNAm while minimizing random noise from individual CpGs.

Our novel principal-component versions of six clocks show agreement between most technical replicates within 0 to 1.5 years, equivalent or improved prediction of outcomes, and more stable trajectories in longitudinal studies and cell culture. This method entails only one additional step compared to traditional clocks, does not require prior knowledge of CpG reliabilities, and can improve the reliability of any existing or future epigenetic biomarker.

PC-based clocks showed greatly improved agreement between technical replicates, with 90+% agreeing within 1-1.5 years. The median deviation ranged from 0.3 to 0.8 years, whereas CpG clocks ranged from 0.9-2.4 years.

PCPhenoAge vs. PhenoAge

The most dramatic improvement was in PhenoAge. CpG-trained PhenoAge has a median deviation of 2.4 years, 3rd quartile of 5 years, and maximum of 8.6 years. In contrast, PCPhenoAge has a median deviation of 0.6 years, 3rd quartile of 0.9 years, and maximum of 1.6 years. PCPhenoAge was trained directly on phenotypic age based on clinical biomarkers rather than DNAm.

Correlations between different PC clocks was stronger than between CpG clocks. This may be partly due to the shared set of CpGs used to train PCs, or due to the reduction of noise that would have biased correlations towards the null. Correlations between PC clocks and CpG clocks tended to be stronger compared to correlations between CpG clocks and CpG clocks, consistent with a reduction of noise.

PC clocks preserve relevant aging signals unique to each of their CpG counterparts. They reduce technical variance but maintain relevant biological variance.

PCA is a commonly used tool and does not require specialized knowledge. High reliability of principal component-based epigenetic clocks will make them particularly useful for applications in personalized medicine and clinical trials evaluating novel aging interventions.”

https://doi.org/10.1093/geroni/igab046.015 “A Computational Solution to Bolster Epigenetic Clock Reliability for Clinical Trials and Longitudinal Tracking”


I appreciate that a coauthor – who is the originator of PhenoAge – is open to evidence and improvements. There’s a fun do-it-yourself demo of PCA at https://setosa.io/ev/principal-component-analysis/.

I found this study from it citing a 2021 review:

https://www.sciencedirect.com/science/article/abs/pii/S1084952121000094 “Aging biomarkers and the brain” (not freely available)

I found that review from it citing a 2020 study:

https://www.cell.com/iscience/fulltext/S2589-0042(20)30384-9 “Human Gut Microbiome Aging Clock Based on Taxonomic Profiling and Deep Learning”

Maybe this last study could be improved from its “mean absolute error of 5.91 years” with PCA? See Part 2 for another view.


PXL_20210704_092829847

Adaptive and innate immunity

Two 2021 reviews presented aspects of human immune systems:

“The adaptive immune system’s challenge is to protect the host through generation and differentiation of pathogen‐specific short‐lived effector T cells, while in parallel developing long‐lived memory cells to control future encounters with the same pathogen.

The system highly relies on self‐renewal of naïve and memory T cells, which is robust, but eventually fails. Genetic and epigenetic modifications contribute to functional differences in responsiveness and differentiation potential.

Less than 20% of nascent T cells are produced from the thymus in young adults, which dwindles to less than 1% after the age of 50 years. Even in young adults, the majority of T cells are produced in the periphery. A pickup in proliferation has been described in late life, possibly as a consequence of increased cell death and evolving lymphopenia.

One challenge of the aging process is to replenish cells while keeping integrity of the organ. The dynamic lymphoid system employs a vast number of T cells (>1011) and maintains a balance between cell production, death, and differentiation.

Enormous TCR ( T cell receptor) diversity is required to be able to respond to the universe of possible peptides (>209). Only T cell generation in the thymus can add new TCR specificities. Homoeostatic proliferation at best maintains diversity, >108 unique TCRs in a given adult.

Antigen-specific memory T cells adopt several fates with age:

  • Decrease in stem-like memory T cells;
  • Increase in NK (natural killer) cell-like TEMRA (terminally differentiated effector T cells);
  • Increase in exhausted T cells;
  • Increase in short-lived effector memory T cells; and
  • Decrease in tissue-residing T memory cells.

Virtual memory T cells without prior experience of antigen encounter also increase with age.”

https://febs.onlinelibrary.wiley.com/doi/epdf/10.1111/febs.15770 “Hallmarks of the aging T cell system”


“Trained immunity is characterized by long‐term functional reprogramming of innate immune cells following challenge with pathogens or microbial ligands during infection or vaccination. This cellular reprogramming leads to increased responsiveness upon re‐stimulation, and is mediated through epigenetic and metabolic modifications.

Trained immunity has been shown to last for at least 3 months and up to 1 year, while heterologous protection against infections can last for at least 5 years. These long-term effects are mediated through reprogramming of myeloid progenitor cells in bone marrow, which in turn generate myeloid cells with a trained immunity phenotype.

Molecular mechanisms underlying trained immunity, for example induced by β‐glucan or Bacille Calmette‐Guérin (BCG) vaccination, can be investigated by using and integrating different layers of information, including genome, epigenome, transcriptome, proteome, metabolome, microbiome, immune cell phenotyping and function. Interplay between epigenetic and metabolic reprogramming is necessary for induction of trained immunity, as certain metabolites have a direct effect on enzymes involved in epigenetic remodeling.

High-throughput methods allow researchers to use an unbiased approach examining many potential genes or markers in relation to health and disease, rather than examining a limited number of candidate genes or markers.

One strength of integrating multiple levels of data is an increased power to identify key regulatory molecular networks driving trained immunity. For example, results obtained from one level (i.e. genes) can be used to reduce the number of traits to test in a second level (i.e. proteins), thereby increasing power.

One important pitfall when it comes to designing effective omics studies, is sample size. With a large number of markers measured, and the relatively small contributing effect size of individual analytes, the risks of both type 1 and 2 errors are high without sufficient sample sizes for both discovery and validation cohorts.”

https://onlinelibrary.wiley.com/doi/pdf/10.1002/eji.202048882 “Resolving trained immunity with systems biology”

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”

Take responsibility for your one precious life – Trained innate immunity

This 2020 review subject was the normal progression of our immune systems:

“Age-related alterations in the immune system result in high susceptibility to infections, increased risk of hospitalization and mortality. Defects in adaptive immunity underlie the markedly low vaccine efficiency in the elderly. Despite reduced cellular functions, a systemic increase in inflammatory markers, so-called inflammaging, is observed in aged individuals.

Trained immunity is a newly emerging concept that showed that innate immune cells possess non-specific immunological memory established through epigenetic and metabolic reprogramming upon encountering certain pathogenic stimuli.

Novel approaches targeting innate immunity to improve host responses are crucial to evade the consequences of the aged immune system. It is an emerging concept that innate immune cells can manifest memory-like properties that are not antigen-specific and exhibit enhanced responsiveness upon later challenges with heterologous stimuli. Whether trained immune responses change as people age is yet to be explored.”

https://academic.oup.com/intimm/advance-article/doi/10.1093/intimm/dxaa052/5885077 “Overcoming immune dysfunction in the elderly: trained immunity as a novel approach”


Previous papers by this review’s corresponding coauthor were curated in:

There’s no reason to rely entirely on the review’s elaborate vaccination schemes to develop trained immunity. Take responsibility for your one precious life and Train your immune system every day!