Control group

Combining exercise with sulforaphane, Part 2

gettingwell4 2-3 stars Required further work, Stress

A 2026 review by the researchers of Combining exercise with sulforaphane provided background for that study:

“This review summarizes redox homeostasis and Nrf2 signaling during exercise and training, how these processes are impacted during aging, and the current evidence for and against combining phytochemicals known to activate Nrf2 signaling (i.e., astaxanthin, curcumin, and sulforaphane) with exercise in older populations. We also highlight mechanistic differences between exercise- and phytochemical-induced Nrf2 activation and consider whether combining these two interventions could enhance redox resilience more than either alone.”

https://www.sciencedirect.com/science/article/abs/pii/S0891584926010427 “Exercise and phytochemicals as modulators of redox homeostasis in aging” (not freely available) Thanks to Dr. Ethan Ostrom for providing a copy.

I was put off that three relevant subjects weren’t discussed. First, Nrf2 activation from exercise under fluorescent lights indoors isn’t equivalent to Nrf2 activation from the same exercise conducted outdoors.

Second, nowhere in this review was Nrf2 activation from sulforaphane described as an exercise mimetic although their study found sulforaphane to be a more effective Nrf2 activator than exercise, even hitting a ceiling effect for the dose used. Sulforaphane was also more comprehensive, activating all four target genes of their chosen Nrf2 panel, whereas exercise missed one.

Third, hormetic effects weren’t discussed, and were misdirected into homeostasis arguments. The result is not interpreting data within an appropriate paradigm, such as this graphic promoting redox homeostasis:

Promoting an inappropriate redox homeostasis paradigm led to misunderstanding and measuring the wrong things, and measuring the correct things inappropriately. For example, these reviewers fashioned a redox homeostasis Goldilocks argument to misinterpret both the hormesis findings of Sulforaphane in the Goldilocks zone and the disconfirming basal Nrf2 levels of other studies. Nevermind that Nrf2 activation lasts for only 15-20 minutes before cells return to baseline Nrf2 conditions.

I suppose that even misguided human sulforaphane research could advance science, though not optimally. For example, mitochondria research has advanced although studies seldom control for light exposure.

I don’t cover this review’s curcumin and astaxanthin research due to the reviewers’ misguided slant. I’d like to see this paper’s peer review comments.

I’m in my seventh year of eating broccoli sprouts every day, and am patiently waiting for research efforts to catch up. I’m not optimistic that people will voluntarily chew something that will never taste good. I expect that people will default to a less effective pill.

Take inulin to improve cognition?

gettingwell4 4-5 stars Advanced knowledge, Cerebrum, Memory, Stress , , , ,

A 2026 rodent study investigated effects of inulin intake:

“This study investigated whether the prebiotic inulin could improve vascular cognitive impairment (VCI) by restoring medial prefrontal cortex (mPFC) GABAergic function via the gut-brain axis. The mPFC, a hub for executive functions such as working memory and decision-making, is particularly vulnerable to vascular insults.

Clinical and preclinical evidence consistently implicates mPFC dysfunction as a critical contributor to cognitive deficits in VCI. Inulin reversed VCI-induced reductions in GABAergic synaptic transmission and GABA levels, which positively correlated with elevated colon short-chain fatty acid (SCFA) levels.

While prior work has established that direct SCFA administration or fecal microbiota transfer can mitigate brain injury in hypoperfusion models, our data advance the field by identifying a simple dietary intervention that can initiate this protective cascade.

We propose that SCFA-GPR41/43 signaling enhances the presynaptic GABAergic machinery, thereby strengthening inhibitory tone. This restored inhibition was associated with a reduction in neuroinflammation and oxidative stress, effects that were reversed upon GABAergic blockade, suggesting that the reinstated GABAergic activity may actively suppress glial activation and promote a synaptic environment conducive to plasticity.”

https://link.springer.com/article/10.1186/s40168-026-02469-8 “Inulin alleviates vascular cognitive impairment by restoring prefrontal GABAergic function via microbiota-SCFA-GPR41/43 axis”

Despite this rodent study’s biological plausibility, there are all sorts of problems translating it into human results that will show cognitive improvement. The primary obstacle is that inulin is unpatentable, and no pharma company can make big money off of running trials for it.

We can wait around to see clinical trial results such as those due in 2027 with the https://clinicaltrials.gov/study/NCT06433037 “Gut-brain Health Effects of PREbiotics in Older Adults With Suspected COgnitive DEcline (PRECODE)” trial (chicory inulin and other fibers for 26 weeks in older adults with subjective cognitive decline) testing working memory, fMRI, and gut-brain markers. But that trial won’t specifically test inulin for alleviating relatively common vascular cognitive impairment.

Photobiomodulation epigenetic effects

gettingwell4 4-5 stars Advanced knowledge, Epigenetics, Stress

A 2026 rodent study investigated effects of 625-635 nm red light:

“We found that periodic exposure to red light significantly increased H3K9ac levels in the tissues and organs of aged mice. Following red light exposure, SIRT4 protein levels in keratinocytes were notably reduced, while glycolysis, fatty acid metabolism, and the tricarboxylic acid (TCA) cycle were significantly activated.

Further mechanistic investigations suggested that the reduction in mitochondrial SIRT4 levels enhances the acetylation of mitochondrial metabolic proteins, particularly malonyl-CoA decarboxylase (MCD), a potent inhibitor of the key rate-limiting enzyme carnitine palmitoyltransferase 1A (CPT1A) in fatty acid oxidation. This process promotes mitochondrial fatty acid oxidation and TCA cycle activity.

Additionally, the decrease in SIRT4 activates SIRT1 through feedback mechanisms, thereby alleviating its inhibition on PPAR-α in senescent keratinocytes and comprehensively activating the expression of genes related to lipid metabolism. This lipid metabolism activation ultimately facilitates the accumulation of acetyl-CoA within keratinocytes, increases H3K9ac levels, and reshapes the expression patterns of senescence-related genes.

Consequently, it mitigates the dysregulation of genomic expression and excessive inflammatory activation associated with cellular senescence. Ultimately, cellular aging is effectively mitigated through the synergistic regulation of metabolism, inflammation, and genomic expression.

Our study reveals a novel anti-aging intervention strategy targeting SIRT4 downregulation to increase H3K9ac levels. We propose that controlling the abnormal age-related activation of SIRT4 during cellular senescence and developing SIRT4 inhibitors may enable tissue-specific senescence reversal and therapeutic interventions for metabolic diseases.”

https://elifesciences.org/articles/111498#content “Photo-downregulation of SIRT4 mitigates aging in mice by enhancing H3K9ac via fatty acid metabolism”

This paper is a good example of productive peer review. Changes made by these researchers were summarized as:

“We have clarified the wavelength specificity of the red-light response, reanalyzed and more cautiously interpreted the omics data, improved the presentation and quantification of semi-quantitative experiments, revised statistical reporting, corrected gene/pathway annotations, toned down mechanistic claims where direct evidence was insufficient, and expanded the Discussion to integrate recent evidence on red-light-induced fatty acid oxidation and AMPK/ACC signaling.”

Grok’s comparisons of this paper to similar studies included:

The paper adds a novel, keratinocyte-focused SIRT4–fatty-acid–H3K9ac axis that helps explain how red light can sustain metabolic activation and reshape age-related gene expression. It is complementary to the well-documented TGFβ/collagen and classic mitochondrial ATP pathways rather than a replacement for them. Direct head-to-head comparisons of effect size, long-term durability, optimal wavelength/fluence combinations (red vs. NIR or dual), and human translation are still limited—standard caveats for mechanistic mouse PBM work. Overall, it strengthens the case that red light’s benefits involve coordinated metabolic and epigenetic remodeling, not just surface collagen stimulation.

Sprout grain for your brain

gettingwell4 4-5 stars Advanced knowledge, Brain development, Epigenetics, Hippocampus, Limbic system, Memory , , ,

A 2026 rodent experiment investigated effects of eating sprouted quinoa:

“A growing body of evidence has highlighted the effectiveness of whole-grain diets in ameliorating obesity and obesity-associated cognitive decline. Our study not only demonstrates beneficial effects of germinated quinoa flour (GQF) on high fat diet (HFD)-induced cognitive impairment, but also elucidates the underlying mechanisms via a specific gut microbiota–metabolite–brain axis.

Using multi-omics combined analysis, we identified key bioactive mediators, core gut microbiota, bacterial enzymes, and brain response genes involved in improvement of cognitive dysfunction by GQF. We demonstrate for the first time that GQF is more effective than quinoa flour (QF) in preventing obesity-induced cognitive impairment.

Research approaches including fecal microbiota transplantation (FMT), functional validation of core bacteria, supplementation of bioactive mediators, and specific blockade of target molecules were utilized to elucidate the causal mechanisms by which GQF alleviates learning and memory dysfunction through the gut microbiota–ferulic acid (FA)–brain axis in obese mice. We demonstrated that GQF-enriched R. hominis and R. intestinalis promote the in vivo release of bound FA from GQF via feruloyl esterase (FAE) activity, increase FA tissue distribution, and thereby target the FA–mitophagy–synapse signaling axis to ameliorate cognitive impairment.

Liberated FA promotes neuronal growth and synaptic plasticity by activating PINK1/Parkin-dependent hippocampal mitophagy. Consistent increases in synaptic proteins, including BDNF, PSD-95, and SYP, together with enhanced dendritic spine density and improved synaptic ultrastructure, further support beneficial effects of GQF on synaptic function.

We further demonstrate that FA, as a key polyphenol enriched in GQF, is liberated by intestinal Roseburia and subsequently participates in the regulation of hippocampal mitophagy and mitochondrial function, thereby maintaining synaptic integrity and normal cognitive function.

Relative abundances of R. hominis and R. intestinalis showed a positive correlation with brain FA concentrations in GQF-intervened obese mice (Figure 5P,Q). Together, these results indicate that dietary GQF intake promotes microbial FA release by enriching Roseburia, thereby increasing FA availability and distribution in the brain and other peripheral tissues.

These findings highlight the critical role of the gut microbiota‑substrate co‑dependent effects in dietary nutritional interventions, and provide mechanistic insights into novel therapeutic strategies for metabolic-associated neurodegenerative diseases.”

https://advanced.onlinelibrary.wiley.com/doi/10.1002/advs.76686 “Gut Microbial Release of Ferulic Acid From Germinated Quinoa Alleviates Obesity-Associated Cognitive Impairment by Activating Hippocampal Mitophagy Associated with PINK1/Parkin Pathway”

I’ll assert that this July 2026 study’s results may be extrapolated to other sprouted grains, most of which contain bound ferulic acid. However, this study’s findings weren’t included in two mid-2026 reviews on the subject:

A bubble tea clinical trial

gettingwell4 4-5 stars Advanced knowledge

A 2026 randomized, double-blind, placebo-controlled clinical trial evaluated effects of adding inulin to bubble tea tapioca pearl boba:

“Fifty women (BMI ≥27 or waist >80 cm; age 20-50 years) were randomized to receive either I-fiber pearl or placebo (2 packs/day, 100 g/pack). After 12 weeks, the I-fiber group showed significant reductions in body weight, BMI, body fat mass, visceral fat, total cholesterol, and LDL cholesterol. I-fiber pearl improved body composition and lipid profiles, suggesting potential benefits as a functional supplement for obesity management.

Participants in the I-fiber pearl group consumed approximately 8.3 g of chicory inulin daily. Macronutrient composition of placebo was matched to that of I-fiber pearl, with the sole difference being the absence of dietary fiber.

No adverse effects were observed in physiological parameters, hematological and biochemical markers, dietary intake, or physical activity levels, indicating that I-fiber pearl was well tolerated and safe. Further studies are necessary to clarify optimal conditions under which inulin supplementation most effectively supports weight, fat mass, and body composition management.”

https://www.jfda-online.com/journal/vol34/iss2/5/ “Evaluating the efficacy of I-fiber pearl on reducing body fat accumulation in obese females: A randomized, double-blind, and placebo-controlled trial”

It’s apparently easier to trick obese young women into doing something healthy than to just give them inulin as a substitute for their preferred beverage sweetener.

I hadn’t noticed after changing suppliers over the past five years that my daily inulin intake of a teaspoon had decreased:

I could double the daily dose to be closer to this trial’s 8.3 grams of chicory inulin. I don’t have much of a sweet craving, though.

Vitamin C and bone marrow aging

gettingwell4 4-5 stars Advanced knowledge, Epigenetics, Immune system, Stress

A 2026 primate study from the same group that performed The return of the free radical theory of aging investigated effects of vitamin C on bone marrow cells:

“We map the single-cell transcriptomic landscape of primate bone marrow aging and demonstrate that long-term oral vitamin C (VC) supplementation attenuates selected molecular and progenitor-level decline. Aging drives severe common lymphoid progenitor (CLP) depletion, myeloid-biased hematopoietic stem and progenitor cell (HSPC) output, and anatomical site-specific molecular adaptations.

VC administration partially offsets these phenotypes, expanding the CLP pool and rebalancing lineage commitment trajectories. This aligns with a ∼4-year reduction in transcriptomic age estimates, cross-validated by an epigenetic clock. Cell-cell communication analyses revealed that VC remodels intercellular signaling, nominating a VC-responsive, progranulin (GRN)-linked candidate pathway.

As the core of the hematopoietic system, bone marrow sustains lifelong production of all blood lineages, making it a central determinant of immunity and systemic homeostasis. With advancing age, however, bone marrow function declines markedly. This deterioration is characterized by diminished regenerative capacity of HSPCs, myeloid-biased differentiation, and impaired lymphoid potential. Complexity of bone marrow aging is further amplified by its anatomical heterogeneity.

We conducted a 40-month longitudinal study (roughly equivalent to 10 human years). Aged female cynomolgus monkeys (12–16 years old, equivalent to approximately 40–53 human years) were randomized into two groups: one receiving daily oral VC (30 mg/kg) and a control group receiving water.

We combined a prolonged oral VC regimen in non-human primates with deep single-cell transcriptomic mapping of anatomically distinct bone marrow compartments to investigate aging-related molecular adaptations. We observed that VC supplementation was characterized by a partial mitigation of aging-associated compositional dysregulation, including higher observed CLP frequencies, and correlated with lowered biological age predictions at both transcriptomic and epigenetic levels.

This study provides a valuable resource and a benchmark dataset for dissecting modifiable components of primate bone marrow aging, establishing a programmatic framework to guide future functional interrogation of VC-responsive candidate pathways.”

https://www.sciencedirect.com/science/article/abs/pii/S193459092600233X “Vitamin C attenuates primate bone marrow aging at the molecular and progenitor level” (not freely available)

These researchers didn’t confirm, but this study’s intervention group may have been the same as “Vitamin C conveys geroprotection on primate ovaries” mentioned in 2026 diet and supplement changes.

It was encouraging that vitamin C partially reverses bone marrow cells’ age-associated myeloid skewing and lymphoid depletion. It may be too intrusive to directly assess HSPCs in human trials.

Nrf2 insufficiency

gettingwell4 2-3 stars Required further work, Epigenetics, Immune system, Stress , ,

A 2026 review argued for a Nrf2 biomarker panel to evaluate Nrf2 insufficiency:

“NRF2 is a central transcriptional regulator of cellular defence against oxidative and electrophilic stress. By coordinating antioxidant buffering, xenobiotic detoxification, and recovery programs, NRF2 helps tissues maintain function despite continual exposure to metabolic by-products and environmental challenges.

In healthy physiology, NRF2 signalling is tightly controlled by the Keap1-NRF2 axis and ubiquitin-mediated degradation, which keeps basal activity low while preserving rapid inducibility when stress rises. Because NRF2 signalling is dynamic and cell-type-specific, interpretation improves when localization, target induction, and functional assays agree. Such triangulation reduces misclassification in heterogeneous clinical samples collected outside peak responses.

We discuss practical readouts, including NRF2 target gene panels, oxidative damage biomarkers, and functional proxies that capture mitochondrial function, inflammatory tone, and barrier integrity in accessible samples. We then evaluate strategies to counteract NRF2 reduction, from exposome and lifestyle change to nutritional, pharmacologic, and targeted delivery approaches, with emphasis on benefit, risk, and reproducibility.

NRF2 insufficiency describes a state in which cells fail to mount an adequate ARE program when confronted with oxidative or electrophilic stress, resulting in weaker detoxification, lower glutathione support, and reduced stress tolerance across diverse organ systems. Therapeutic strategies for NRF2 insufficiency should be framed as restoration of the adaptive range, rather than indiscriminate activation.

We defined low NRF2 activity as a functional deficit in inducible protection, rather than as a single static marker measured at rest. Lifestyle and exposome interventions can remove suppressors and introduce hormetic inputs, while nutritional, pharmacologic, and targeted delivery approaches may provide more direct engagement when disease burden is high.”

https://www.techscience.com/biocell/online/detail/27486 “NRF2 Insufficiency in Chronic Disease”

One problem with reviewers in general is that they only see what’s in their paradigm. Three related omissions in this review are: 1) Narrowing Nrf2 hormesis discussion to just exercise; 2) Adopting the widespread p < .05 numerical definition of significant measurements, which ignores the importance of preconditioning; and 3) Not understanding that factors in human Nrf2 responses are very much influenced by our circadian biology.

1. Comparing the above biomarker panel with the panel used in Combining exercise with sulforaphane showed NQ01 and GR hormetic responses to exercise. HO-1 had a non-hormetic linear/curvilinear response to different sulforaphane doses. GCLC didn’t respond to exercise, but it hormetically responded to different sulforaphane doses.

If researchers use Nrf2 biomarker panels, they need to appropriately analyze hormetic and non-hormetic responses.

2.  The second study of Coffee compound effects pointed out:

“Hormetic effects typically show a 30 to 60% stimulation above control. This is far below the 2 to 3-fold greater than control detection limit for statistical significance based on human variability/bioplasticity and are often reported as false negatives.

A weight-of-evidence approach was proposed based on multiple in vivo and in vitro test results to derive a study design strategy to increase detection of hormetic effects within the clinical trial framework.”

But Nrf2 studies don’t do this, again because such responses are deemed numerically insignificant. Looking through the above curated preconditioning papers shows a better understanding of biological significance.

3. The second paper of Broccoli sprouts activate the AMPK pathway, Part 4 pointed out:

“Nrf2 is one of the most cycling genes under control of the circadian clock. Feeding behavior, metabolism and hence AMPK activity follow and substantiate the biological clock, indicating an entangled circadian regulation of metabolic and redox homeostasis.”

There was no recommendation in this review for taking Nrf2 measurements at the same time of day to be comparable in and among subjects and controls. There is a related discussion of epigenetic age clocks in The third phase of reversing aging and immunosenescent trends:

“If you measure your age at 4:00 a.m. versus 11:00 a.m. you’re going to get a different result. It’s dynamic and there’s a trend and over time you change in a certain direction, but over any short period of time you can bounce around a little bit.”

Transcriptomic age

gettingwell4 4-5 stars Advanced knowledge, Epigenetics, Hypothalamus, Immune system, Limbic system, Memory, Stress, Telomeres , , , ,

A 2026 study investigated aging through the use of transcriptomics:

“By constructing transcriptomic clocks of expected mortality across >11,000 samples from mouse, rat, macaque and human, we provide a unified framework that integrates age-associated transcriptional change with the direction and magnitude of lifespan modulation by interventions, enabling a quantitative and biologically interpretable readout of health status.

While chronological clocks captured many detrimental conditions (e.g., chronic diseases or certain short-lived genetic models), they were comparatively less responsive to lifespan-extending interventions, consistent with reports that longevity treatments often only modestly reverse age-associated transcriptomic signatures. In contrast, mortality clocks robustly distinguished both short- and long-lived models and showed strong associations with human time-to-death, approaching the predictive performance of second-generation DNAm mortality clocks while remaining biologically interpretable.

Our results support and extend DNAm-based observations that heterochronic parabiosis in old animals and early embryogenesis can induce molecular age deceleration. In old heterochronic parabionts, mortality clocks detected a sustained tAge reduction that persisted for 2 months after detachment from young partners. Together, these findings support the view that early development contains a conserved rejuvenation-like phase, and that systemic environment can partially reset molecular age later in life.

https://www.nature.com/articles/s41586-026-10542-3 “Universal transcriptomic hallmarks of mammalian ageing and mortality”

Applying this study to An environmental signaling paradigm of aging theory and its derivative studies through Reversing biological age in rats and https://link.springer.com/article/10.1007/s11357-023-00980-6 “Reversal of biological age in multiple rat organs by young porcine plasma fraction” could clarify involved mechanisms. This research area doesn’t have current sponsors, though, to carry out rat lifespan studies.

I apologize in advance for formatting weirdness. WordPress eliminated my old editing preference.

Add vitamin C to broccoli sprouts?

gettingwell4 2-3 stars Required further work

A 2026 paper presented results of a clinical trial that selectively added myrosinase enzyme via mustard powder and vitamin C to measure in vivo effects on glucoraphanin conversion to sulforaphane:

“Effects of exogenous myrosinase (Myr) on conversion efficiency of glucoraphanin (GR) to sulforaphane (SF) was compared to gut microbial Myr-like activity. In a randomized, double-blind, crossover study, sixteen subjects (9 F: 7 M) received a single oral dose of GR in 385 mg broccoli seed extract (BSE) with 72.5 mg Myr-containing mustard seed powder, or broccoli seed extract alone, both with 100 mg ascorbic acid.

GR + Myr, on average, doubled the bioavailability of SF (39.8 ± 3.1%) compared to GR alone (18.6 ± 3.1%), and increased the conversion rate in the first 8 h (25.4% ± 2.7%) compared to GR alone (8.0% ± 2.7) based on measurement of urinary metabolites. The majority of subjects given GR as BSE with exogenous Myr and Vit C, converted GR to SF notably faster (e.g., within the first 8 h), than those given GR and Vit C alone.

One of the most likely explanations for the pronounced differences is that when SF was produced as a result of added exogenous Myr, it was produced and absorbed in the small intestine and metabolized primarily to its glutathione (GSH) derivatives and excreted in urine. This is a more rapid process than when GR passes into the large intestine and then is acted upon by the greater bacterial population within that terminal segment of the gastrointestinal system.

No differences were observed in the 8 to 24 h urine collection (Time 24 h) between the two treatments: 11.7 ± 1.3% for GR + Myr vs. 8.9 ± 1.3% for GR alone. Bacterial communities did not differ between low/high GR converters following supplementation.

Many bacteria which persist in the small intestine and upper large intestine, as well as in mucosal-associated fractions, are not well represented in feces. The lack of anatomically specific microbial communities in the human gut limits our knowledge of GR conversion in people.”

https://www.nature.com/articles/s41598-026-39389-4 “Exogenous myrosinase from mustard seed increases bioavailability of sulforaphane from a glucoraphanin-rich broccoli seed extract in a randomized clinical study”

1. Lost in this study’s shuffle was the reason why sulforaphane’s effects are beneficial in the first place. As Switch on your Nrf2 signaling pathway pointed out:

“We use N-acetylcysteine (NAC) in the lab all the time because it stops an Nrf2 activation. So that weak pro-oxidant signal that activates 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.”

It’s relevant to the Nrf2 activating effects of sulforaphane when antioxidant vitamin C taken to increase myrosinase hydrolyzation of glucoraphanin to sulforaphane if this vitamin C dose may also block Nrf2 activation. An increase of sulforaphane and its metabolites wouldn’t physiologically matter if their beneficial effects were simultaneously blocked.

2. Another indicator that these researchers lost the plot was shown when they asserted: “These data suggest that the present study may not have included sufficient AA to optimize Myr enzyme activity in vivo, another consideration for future studies” based on comparing the in vitro Reference 21 ascorbic acid doses (0, 11, 44, 88, or 154 mg AA/capsule). I don’t have access to Reference 21 to see whether it also didn’t assess Nrf2 activation.

3. For comparison of this study’s 50 mg glucoraphanin dose on two non-consecutive days, the cited Our model clinical trial for Changing to a youthful phenotype with broccoli sprouts provided daily 30 grams of fresh broccoli sprouts that contained an estimated 51 mg of glucoraphanin for ten weeks. Although no broccoli sprout preparation or intake guidelines were enforced, unassisted glucoraphanin conversion to sulforaphane had many beneficial effects in that trial.

4. These researchers stated “No differences were observed in the 8 to 24 h urine collection (Time 24 h) between the two treatments.” Whether the faster small intestine absorption of sulforaphane had benefits over the slower large intestine absorption wasn’t investigated.

5. I’ve previously corresponded with one of this study’s coauthors, and think their research group could do better work without the retired broccoli sprout expert. Maybe they would take more confident ownership of their work if they let him ride off into the sunset, and decide for themselves what predictable findings would be in their research effort’s scope?

Maybe they wouldn’t let fester the same old issues in his papers? It doesn’t say anything good about current research if its main findings just repeat last decade’s findings.

For example, Table S4 has stories that weren’t told. It conforms to the expert’s cited 2015 study findings, but presenting averages doesn’t reveal causes for individual differences. So questions on the individual level continue to be unanswered, such as:

  • Subject 8 had more than a fivefold increase of glucoraphanin-only conversion to glucoraphanin + myrosinase conversion. What blocked the other subjects from achieving similar results?
  • Why was Subject 10 so far behind everyone else’s capabilities? They would have had to increase their glucoraphanin-only conversion by fourfold just to get to the next lowest person’s level, Subject 15, but sixfold to get to Subject 15’s glucoraphanin + myrosinase conversion level.

6. Every researcher wants to have an impact on their field. The time to think over how to newly research possible impactful outcomes is before the study starts.

Since I’m in my seventh year of eating broccoli sprouts every day, I would have paid close attention to more rigorous bioavailability, more exact microbiota collection techniques, or detailed exploration of differences in people’s responses to the same treatments, all of which were predictable issues beforehand. I didn’t really care for listing them in the Discussion section, then dismissing investigations of these findings for some future research to explore.

Self-reinforcing feedback loops of aging

gettingwell4 4-5 stars Advanced knowledge, Epigenetics, Memory, Stress, Telomeres , , , ,

A 2026 rodent study investigated age-associated queuine decline. Queuine is characterized as a “longevity vitamin” in the cited 2018 review Prolonging healthy aging: Longevity vitamins and proteins, along with ergothioneine, astaxanthin, and taurine.

“The contribution of transfer RNA (tRNA)-specific modifications to aging remains largely unexplored. We systematically profile tRNA modifications across multiple organs, species, and senescence models, and identify mannosyl-queuosine (manQ) as the first tRNA-specific modification that consistently declines with age.

Across species, queuine supplementation extends lifespan and enhances healthspan. In naturally aging mice, long-term oral administration beginning at 16-months-old (human equivalent 50 years) extends mean lifespan by 15.3%, reduces DNA methylation age, improves cognitive and motor performance, strengthens antioxidant defenses, remodels the gut microbiota, and alleviates inflammation and metabolic dysfunction without detectable toxicity.

These findings establish tRNA epitranscriptomic remodeling as a previously unrecognized layer of aging regulation, and identify restoration of manQ through queuine supplementation as a multi-system strategy to delay aging.

manQ hypomodification is selective rather than reflecting global tRNA depletion. Aging preferentially reduces the manQ-containing tRNAAsp fragment while leaving the corresponding unmodified tRNAAsp fragment, and other queuosine-modified tRNAs, relatively unchanged.

This pattern supports a regulated defect in modification homeostasis rather than a generalized change in transcript abundance. Such specificity argues that manQ loss is not merely a passive consequence of tissue degeneration, but instead represents a conserved, biologically meaningful aging-associated event with mechanistic impact.

Because proteostasis intersects with multiple canonical hallmarks (e.g. mitochondrial dysfunction, impaired stress resilience, and altered intercellular communication), translation-coupled proteome destabilization offers a unifying explanation for how a single tRNA modification defect can elicit multi-system consequences. In this view, manQ decline is not merely one of many molecular changes observed in aging, but rather a proximate determinant capable of amplifying downstream hallmarks through a common axis of proteome quality control.

Our findings further suggest that manQ depletion may engage self-reinforcing feedback loops that accelerate aging trajectories. This architecture offers a conceptual framework in which aging progressively erodes ‘epitranscriptomic integrity’ at the tRNA level, pushing translation toward an error-prone regime that accelerates proteostatic collapse and functional decline.

A distinctive implication of this work is that queuine introduces a microbiota-host epitranscriptomic axis into aging biology. Queuine is produced by gut microbiota and cannot be synthesized de novo by mammals. These findings expand the conceptual scope of geroscience by placing a microbiota-derived nutrient upstream of translational quality control.

Queuine supplementation offers a distinct therapeutic logic: rather than modulating a single signaling cascade, it restores a tRNA modification state that governs translational fidelity – an upstream determinant of proteome quality that can, in principle, influence multiple downstream hallmarks concurrently. These findings highlight an intervention paradigm centered on restoring molecular fidelity, rather than suppressing a single downstream phenotype, as a strategy to delay systemic aging.”

https://www.biorxiv.org/content/10.64898/2026.03.22.713446v1.full “Evolutionarily Conserved Decline of tRNA Mannosyl-Queuosine Links Translational Regulation to Aging and Is Reversed by Queuine”

Treat your gut microbiota well. Give them what they want, and expect reciprocity.

The hops compound xanthohumol

gettingwell4 4-5 stars Advanced knowledge, Stress

Two 2026 papers, with the first an in vitro study of over 2000 compounds to select those that best inhibit BACH1:

“BACH1 regulates the cellular oxidative stress responses by suppressing expression of cytoprotective genes. Dysregulated BACH1 activity has been implicated in a range of pathologies, including chronic inflammatory diseases, fibrosis, and cancer, making it a promising therapeutic target.

We identified four structurally distinct compounds that robustly inhibit BACH1 function. Notably, these compounds simultaneously activate transcription factor NRF2, suggesting the potential for a broader modulation of oxidative stress pathways.

However, while NRF2 induces expression of genes that protect against oxidative stress and inflammation and suppress ferroptosis, BACH1 represses them. While NRF2 broadly activates cytoprotective genes, BACH1 inhibition triggers a more restricted response but with a strong upregulation of HMOX1 (significantly stronger than the one obtained upon NRF2 activation).

As such, combined NRF2 activation and BACH1 inactivation is expected to produce a more potent antioxidant and anti-inflammatory effect than targeting either factor alone. Moreover, BACH1 regulates unique targets not shared with NRF2 and can dominantly repress genes even in the presence of active NRF2. This confers BACH1 inhibition distinct therapeutic value, particularly in contexts such as cancer cell invasion, where its suppression yields anti-metastatic effects.

  1. Auranofin is an FDA-approved gold salt used in rheumatoid arthritis whose primary mechanism of action is inhibition of thioredoxin reductases (TrxRs).
  2. Xanthohumol is a natural compound, prenylated chalcone, that belongs to the flavonoid family, with reported antimicrobial, anti-inflammatory, and antioxidant activities, and demonstrated safety in phase I and phase II trials.
  3. Alantolactone is a natural compound, member of the sesquiterpene lactone class with anti-inflammatory and antioxidant effects, and has been tested in several animal models without reported toxicity.
  4. CH55 is a synthetic retinoid with high affinity for RAR-α and RAR-β and antifibrotic activity and has not been yet tested in vivo.

In summary, this work establishes a robust screening platform for identification of functional BACH1 inhibitors, and provides new chemical scaffolds with potential for future therapeutic development.”

https://papers.ssrn.com/sol3/papers.cfm?abstract_id=6439073 “Development of a High-Throughput Screening Platform for Identification of Functional BACH1 Inhibitors Reveals Compounds with Anti-Invasive Potential”

Xanthohumol is ninth on the Nrf2 activator list. BACH1 interactions were also covered in Part 3 of Broccoli sprouts activate the AMPK pathway.

A 2026 paper that was too recent to be referenced in the above study described two xanthohumol clinical trials. The first trial was designed to assess bioavailability in healthy people (6 men and 6 women), and the second was designed to determine bioactivity in 16 healthy women:

“The aim of the present project was to systematically investigate bioavailability of native xanthohumol compared to micellar xanthohumol at two doses (86 mg vs. 172 mg) in a randomized crossover trial. We furthermore examined short-term effects of xanthohumol on resting energy expenditure (REE), blood pressure (BP), and heart rate (HR) in a randomized placebo-controlled crossover study.

Micellar solubilization significantly increased area under the curve (AUC), maximum plasma concentration of xanthohumol (Cmax), timepoint of maximum plasma concentration of xanthohumol (tmax), and apparent bioavailability compared to native xanthohumol. The dose also significantly influenced plasma kinetics, but apparent bioavailability and tmax were dose-independent in contrast to AUC and Cmax. In our subsequent study, xanthohumol did not affect REE, substrate oxidation, BP, or HR.

Two properties of xanthohumol impair its bioavailability. First, xanthohumol is relatively unstable in an acidic environment, and second, xanthohumol is highly lipophilic and hydrophobic, insoluble in the aqueous environment of the intestinal lumen, and poorly absorbed into enterocytes.

In addition to determining typical plasma kinetic parameters (e.g., Cmax, tmax, and AUC), we also calculated the amount of xanthohumol absorbed using maximum plasma xanthohumol concentration. These estimated amounts are minimum quantities of xanthohumol that had to be absorbed to achieve observed plasma xanthohumol concentrations.

Results of these calculations emphasized the relatively poor bioavailability of xanthohumol in humans. Only ∼0.1% and ∼1.2% of native and micellar xanthohumol were absorbed, respectively.

However, a limitation of this plasma estimation is that fractional absorption of xanthohumol was underestimated because distribution of xanthohumol in cells and tissues was not taken into account. It is likely that more xanthohumol was actually absorbed. Whether the bioavailability of xanthohumol is sufficient for physiological efficacy must be investigated further in humans.

In conclusion, oral bioavailability of micellar xanthohumol was higher than that of native xanthohumol. Systemic availability of xanthohumol did not differ between men and women. Our study provides no evidence that xanthohumol acutely affects REE, BP, and HR.”

https://onlinelibrary.wiley.com/doi/10.1002/mnfr.70413 “The Bioavailability of Xanthohumol in Humans and the Influence of Formulation and Dose: Randomized Controlled Trial Data”

2026 diet and supplement changes

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I switch things around pretty often, but I haven’t said much about diet and supplement changes since this time last year. Here’s what I’ve done in terms of changes that I’ve since abandoned or reduced, followed by additions or increases that I’ve kept.

Abandoned and reduced items

1. I stopped using Avena sativa oats to grow 3-day-old oats sprouts. I again ran into the same situation where I got < 10% yield.

The first time this happened in 2023, I related to the Montana farmer that degraded seed vitality was probably caused by the way that Amazon handled their oat products. I’m the customer, though, and I won’t make it my problem if the vendor can’t meet expectations.

I switched to sprouting Avena nuda oats based on Sprouting hulless oats. I’ll note that this Illinois farmer doesn’t let Amazon handle their organic Avena nuda oats, and they add on post office shipping costs. They don’t recommend sprouting, probably because of liability, although I’ve had a 91% germination rate over three days. I might have ordered Avena sativa oats directly from the Montana farmer bypassing Amazon if they were also organic.

2. I stopped taking alpha ketoglutarate. In my view, increasing tricarboxylic acid (TCA) cycle intermediate metabolites such as alpha ketoglutarate and CoQ10 should not be the primary way to improve mitochondrial electron transport chain function.

Instead of biochemical considerations, focus on photon modulation, which precedes biochemical reactions. Which means mitochondrial studies should be controlled for light exposures, and very few of them do that, although it’s the way nature works.

This past winter I increased indoor non-LED light exposure within a circadian rhythm framework. I’ll switch back to walking the beach at sunrise from being out in mid-day sun after it gets a little bit warmer.

3. I’ve taken creatine on and off during the past year. There’s a bit of literature on its use for improving methyltransferase system components like homocysteine.

Stopping creatine fits one of the overall patterns that studies demonstrate – people who are initially deficient in the studied item get a benefit, while people who are initially sufficient don’t benefit from treatment. I’ve always tested mid-range for homocysteine, which is desirable.

4. I had some cocoa powder lying around for a year or two, and I used it this past winter to improve the taste of coffee I bought on sale. Cocoa flavanols are supposed to improve various health measures. But I haven’t been provided access to the most recent human studies, so I won’t repeat their results without reading their details.

5. I saw this at Costco, and picked up a package:

A 2025 review covered pecan research, Pecans and Human Health: Distinctive Benefits of an American Nut. Eating pecans seems to have some health benefits, and they taste alright.

For me, though, the dryness of a chewed pecan bolus creates a swallowing problem that walnuts don’t have. YMMV.

6. I stopped taking 2 g magnesium L-threonate. I’ve always tested high for magnesium without using a specific supplement.

7. I reduced D3 by 25 mcg to a daily 2400 IU. Winter is over.

New and increased items

1. I curated five 2025 ergothioneine studies in Human studies of ergothioneine after stopping mushroom intake via AGE-less chicken soup. I wasn’t thrilled that none of them investigated long-term effects of persistent plasma ergothioneine levels.

This year I decided to start taking the higher 25 mg dose of the first study once a week. That should produce some benefits at a lower ergothioneine blood level than daily doses produce. I’ll check periodically for 2026 research.

2. The only paper I’ve curated on deuterium (heavy hydrogen) is Taurine and mitochondrial health. I started using Icelandic glacier water to make coffee and tea, and for just drinking.

It isn’t advertised as deuterium-depleted water, and it isn’t manufactured as such. But I think any glacier water contains less deuterium than local water. I use local filtered water for sprouting and cooking.

3. Per The return of the free radical theory of aging I started taking extra vitamin C separately from other supplements in the form of Now brand liposomal 1 gram twice daily this past winter. That study found vitamin C to be an anti-aging compound for primates.

Reference 72 of that 2026 paper is a freely available 2025 study https://www.cell.com/cell-stem-cell/fulltext/S1934-5909(25)00339-X “Vitamin C conveys geroprotection on primate ovaries” that used the same vitamin C dose and duration in macaques to find:

“VC slowed aging in various ovarian cell types. Moreover, VC protected human ovarian endothelial and stromal cells (SCs) from aging partially via NRF2 activation. This study establishes a proof-of-concept for delaying primate ovarian aging with a single compound, and provides important insights into preventing and treating degenerative diseases related to ovarian aging.”

4. I restarted taking inulin last year, about 3 grams (a heaping teaspoon) daily after posting Inulin vs. FOS. My 2.5 year-old grandchild takes a level teaspoon daily, as inulin’s beneficial effects aren’t just for old people.

5. I started taking 12 mg astaxanthin twice in the morning. I use Nrf2 activators in the morning because Nrf2 is especially involved in the circadian cycle, as noted in papers such as Broccoli sprouts activate the AMPK pathway, Part 4.

6. I increased daily raw egg consumption from 3 eggs a day to 3 eggs twice daily.

7. This year, Ovega 3 algae oil DHA 420 mg/EPA 140 mg became no longer available AFAIK. I substituted Vegan Omega 3 algae oil DHA 300 mg/EPA 150 mg in the morning and Sports Research Omega 3 fish oil DHA 310 mg/EPA 690 mg in the afternoon.

8. I picked up this Korean seaweed in a 10-pack at Costco. The label doesn’t say what its iodine content is. I eat it as a snack whenever I get a salt craving, maybe once a week.

The return of the free radical theory of aging

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A 2026 primate study investigated effects of vitamin C:

“Here, we define a conserved iron-lipid axis driving primate aging, termed ‘ferro-aging.’ Multi-tissue profiling in humans and non-human primates reveals age-progressive iron accumulation, fueling chronic lipid peroxidation orchestrated by acyl-coenzyme A (CoA) synthetase long-chain family member 4 (ACSL 4). Distinct from acute ferroptosis, this ACSL4-mediated process promotes cellular senescence and systemic functional decline.

We identify vitamin C (VC) as a direct inhibitor of ACSL4. Long-term VC administration in aged monkeys for over 40 months potently reduces ferro-aging signatures across tissues, attenuates multi-organ pathology, and improves neurological and metabolic functions. Multi-omic aging clocks indicate the VC-mediated reversal of biological age.

Despite decades of interest in oxidative stress, largely sparked by the free radical theory of aging, efforts to modulate it broadly with antioxidants have yielded inconsistent or neutral outcomes, highlighting the theory’s limitations and underscoring the need to identify more specific, upstream drivers. A critical challenge remains: determining whether the iron-lipid axis constitutes a core upstream driver of aging in primates and, if so, whether it is therapeutically targetable.

In this study, we bridge these gaps. We define an iron-triggered, ACSL4-governed, lipid peroxidation-driven program that escalates with age across diverse cell types and multiple organs in non-human primates.

VC treatment dose-dependently increased Nrf2 phosphorylation and activation. VC orchestrates a dual-defense strategy against ferro-aging: it directly suppresses the pro-aging lipid peroxidation driver ACSL4, while in parallel, it bolsters the cell’s intrinsic antioxidant capacity via Nrf2 pathway activation.

Middle-aged cynomolgus monkeys (12–16 years old, approximating human 40–50 years) received daily oral VC (30 mg/kg group) or a control treatment for 40 months under standardized conditions.

Structural MRI analysis demonstrated that VC intervention counteracted age-related brain atrophy. Using general linear mixed models, we found that VC restored cortical surface area in the frontal lobes of aged monkeys. Regional analysis identified enlargement in four regions of the orbital frontal cortex, an area critical for adaptive behavior.

Diffusion MRI-based connectomics revealed that, compared with young animals, aged monkeys exhibited reduced structural connectivity in 18 brain regions. VC treatment restored connectivity in 9 of these regions, which were predominantly located in the posterior parietal cortex, a hub for spatial awareness and decision-making.

VC exerted robust neuroprotective effects. It attenuated heterochromatin loss (increased H3K9me3) in the prefrontal cortex and hippocampus and reduced abnormal protein aggregates, including cytosolic aggresomes and Aβ. Additionally, VC lowered the abundance of activated microglia and astrocytes and suppressed expression of the innate immune sensor cGAS in the hippocampus.

VC supplementation reduced the estimated biological age across multiple organs. At the epigenetic level, VC lowered DNA methylation age in several tissues, including brain, brown adipose tissue, muscle, skin, aorta, and kidney. In the hippocampus, the most substantial reductions in biological age occurred in microglia, oligodendroglia, and oligodendrocyte precursor cells. In the pancreas, alpha cells, beta cells, and ductal cells showed the greatest rejuvenation.

In summary, chronic VC supplementation inhibits the ferro-aging pathway, reduces multidimensional biological age across primate organs, and ameliorates a spectrum of functional declines in nervous and metabolic systems. Our work establishes ACSL4 inhibition as a promising and translationally relevant therapeutic strategy for mitigating aging-related decline.

A long-term, 40-month intervention study in aged non-human primates is a highly translational model given their shared inability with humans to synthesize VC endogenously. The finding that a single, safe nutrient can reverse multidimensional aging clocks in a primate has profound implications for translational longevity medicine.”

https://www.sciencedirect.com/science/article/abs/pii/S1550413126000537 “Vitamin C inhibits ACSL4 to alleviate ferro-aging in primates” (not freely available) Thanks to Dr. Pradeep Reddy for providing a copy.

Grok’s take on this study:

“For humans (who, like macaques, cannot synthesize vitamin C), the Recommended Dietary Allowance (RDA) is 75–90 mg/day for adults (~1–1.5 mg/kg for a 60–70 kg person) to prevent deficiency. Upper safe intake levels are much higher: up to 2,000 mg/day (Tolerable Upper Intake Level) is considered safe for most adults, with no established adverse effects at that level from food/supplements.

Treated monkeys represent advanced aging stages (likely equivalent to human 50s–70s+ based on ‘aged’ designation and long-term intervention effects), extending the prior 12–16-year monkey range (human ~35–55) to broader anti-aging applications. While human trials are needed, the primate evidence (long-duration, systemic benefits) strengthens the case for high-dose, sustained vitamin C as a strategy against ferro-aging in humans. It elevates vitamin C from a nutrient to a targeted anti-aging compound in primates.”

Coincidentally, I started taking extra vitamin C separately from other supplements in the form of liposomal 1 gram twice daily this past winter. Can’t say that it had any effects on my intended target, avoiding sniffles and sneezing, as allergy season kicked off in early February. With this study’s findings, I’ll continue.

Eat broccoli sprouts for ALS?

gettingwell4 4-5 stars Advanced knowledge, Acetylcholine, Cerebellum, Cerebrum, Dopamine, Epigenetics, Glutamate, Hippocampus, Immune system, Limbic system, Lower brain, Memory, Neurochemicals, Serotonin, Stress , ,

A 2026 rodent study investigated sulforaphane’s ability to affect ALS-like symptoms:

“The objective of this study was to evaluate neuroprotective efficacy and safety of sulforaphane (SUFP) in a methylmercury (MMHg⁺)-induced preclinical rat model of amyotrophic lateral sclerosis (ALS). ALS is characterized by progressive motor neuron degeneration and muscle wasting, leading to impairments in gait, swallowing, salivation, and routine motor activities.

64 animals were classified into eight groups: 1st: normal control, 2nd: vehicle control; 3rd: SUFP perse (4 mg/kg, i.p.), 4th: MMHg + (5 mg/kg, p.o.), 5th: MMHg + 5 + SUFP (2 mg/kg, i.p.), 6th: MMHg+ 5 + SUFP (4 mg/kg, i.p.), 7th: MMHg+ 5 + omaveloxolone (OVX) (30 mg/kg, i.p.), and 8th: MMHg + 5 + dimethyl fumarate (DIMT) (50 mg/kg, i.p.). Neurotoxin MMHg + was orally administered at 5 mg/kg for the first 21 days. For the next 22 days, SUFP, OVX, and DIMT were administered intraperitoneally (i.p.).

SUFP modulates neurotransmitter levels such as acetylcholine (A), dopamine (B), GABA (C), glutamate (D), and serotonin (E).

SUFP4 exerted broad neuroprotective effects in ALS pathology by restoring antioxidant proteins (Nrf2, HO-1, SIRT1), suppressing apoptotic (Bax, caspase-3, Bcl-2) and inflammatory markers (TNF-α, IL-1β), and enhancing the anti-inflammatory cytokine IL-10. It also downregulated stress-related signaling pathways (PI3K/Akt, p75NTRECD, MAPKs) associated with neurodegeneration. These molecular effects translated into meaningful functional recovery, as evidenced by improvements in grip strength, locomotor performance, spatial memory, and depressive-like behavior.

Histopathological evaluation demonstrated attenuation of demyelination and preservation of neuronal architecture including the cerebral cortex, hippocampus, striatum, midbrain, and cerebellum. Beyond central neuroprotection, SUFP exerted systemic benefits by normalizing hepatic enzymes, improving skeletal muscle integrity, restoring redox balance, stabilizing neurofilament and myelin-associated proteins, and correcting hematological alterations.

Despite limitations related to study duration and animal sex, this work strongly positions SUFP as a promising, multi-target therapeutic candidate for ALS with both neural and systemic protective efficacy.”

https://link.springer.com/article/10.1007/s12035-026-05683-5 “Sulforaphane-Mediated Multitarget Therapeutic Effects in Methylmercury-Induced ALS-Like Pathology: Comparative Analysis and Multifaceted Approach to Neuroprotection and Systemic Recovery” (not freely available) Thanks to Dr. Sidharth Mehan for providing a copy.

Unlike A Nrf2 treatment for ALS?, this study didn’t present evidence that its treatment compound was effective for preventing ALS. For one thing, currently-known disease factors involving heat shock proteins and associated genes, some of which are Nrf2 targets, weren’t investigated.

Two Nrf2 activators were used in both studies as comparators of Nrf2 activation effects. Neither omaveloxolone nor dimethyl fumarate are ALS causal treatments, though, and have undesirable side effects.

A human equivalent of this study’s higher sulforaphane dose is ((4 mg x .162) x 70 kg) = 45 mg. 45 mg of sulforaphane might be too much to consistently take at one time because of unpalatability. But I documented taking an estimated 52 mg for a year during 2020-2021 by eating microwaved 3-day-old broccoli sprouts twice a day.

Nrf2 and stem cells

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A 2026 review subject was mechanisms and therapeutic potential for Nrf2 activators in combination with mesenchymal stem cells:

“Mesenchymal stromal/stem cells (MSCs) are multipotent stem cells that can be isolated from various tissues – such as bone marrow (BM), umbilical cord (UC), adipose tissue (AD), dental pulp (DP), hair follicle (HF), and placenta – and differentiated into multiple lineages under appropriate conditions. Their functional repertoire includes immunomodulation, homing, and differentiation, which collectively help establish a balanced inflammatory and regenerative niche within damaged tissues during severe inflammation. MSCs-derived extracellular vesicles (MSCs-EVs) and conditioned medium (MSCs-CM) play remarkable roles, exhibiting potent anti-inflammatory and antioxidant properties that offer novel therapeutic alternatives for inflammatory diseases.

Therapeutic capacity of MSCs in inflammatory conditions is increasingly attributed to their potent paracrine activity rather than solely to their differentiation potential. A key mechanism underlying this paracrine effect is activation of the Nrf2 antioxidant pathway.

MSCs and their secreted products including exosomes (Exos), EVs, and CM, activate Nrf2 through multi-dimensional/target mechanisms, thereby enhancing cellular antioxidant defenses, modulating immune responses, and promoting tissue repair. It is noteworthy that therapeutic efficacy of MSCs and their derivatives can be enhanced through external modulation, including pretreatment with natural compounds.

Preconditioning refers to brief treatment of MSCs or their derivatives with physical, chemical, or biological factors prior to application, aiming to enhance their ability to counteract oxidative stress and improve their therapeutic efficacy. Flavonoids precondition and prime MSCs via the direct Keap1-Nrf2 pathway or indirect PI3K-Akt pathway, which enhances cellular resilience to adverse conditions by reducing apoptosis and promoting survival. Primed MSCs, in turn, remodel the microenvironment through an altered secretory profile, releasing bioactive factors that create more favorable conditions for their own persistence.

The core logic of these strategies lies in simulating or inducing adaptive stress, such as employing specific chemical molecules or drug stimuli, or utilizing physical / microenvironmental preconditioning to mimic specific physical conditions of the in vivo injury environment. The most straightforward strategy is overexpression of Nrf2 or its key downstream effector molecules.

The majority of existing studies remain at the level of observing correlations with Nrf2 upregulation, and there is still a lack of precise causal validation regarding key upstream signals – such as specific cytokines, miRNAs, or proteins – through which MSCs or derivatives initiate Nrf2 activation. Mechanistic insights are predominantly derived from in vivo or rodent (mouse/rat) model experiments, with a notable absence of clinical validation, insufficient long-term safety and pharmacokinetic data, and a lack of standardization in administration routes and dosages, all of which hinder clinical translation.

The essential role of the Nrf2 pathway has not been rigorously confirmed, as most studies have not employed reverse genetic validation using Nrf2-knockout animals or specific inhibitors. Consequently, it remains unclear whether therapeutic effects are necessarily and exclusively dependent on Nrf2, and potential synergistic contributions from other pathways may have been overlooked.

Most natural flavonoids face challenges such as low oral bioavailability, rapid metabolism, and poor targeting. Numerous challenges remain to be addressed in order to translate these promising preclinical findings into clinical practice. Future research should focus on the following aspects:

  1. Elucidating precise upstream molecular mechanisms by which MSCs activate Nrf2;
  2. Employing more clinically relevant chronic disorder models;
  3. Systematically evaluating long-term safety, optimal delivery strategies (including dosage and route of administration), and immunogenicity of MSCs-based therapies;
  4. Validating selection criteria (optimal source), quality control, batch-to-batch consistency of MSCs, and addressing regulatory and ethical barriers to clinical translation; and
  5. Integrating molecular docking, ADMET (Absorption, Distribution, Metabolism, Excretion, Toxicity) prediction, and in vitro and in vivo validation to further elucidate regulatory effects of flavonoids and enhance understanding of their mechanisms of action.”

https://link.springer.com/article/10.1186/s13287-026-04925-6 “Activation of Nrf2 with natural flavonoids and mesenchymal stromal/stem cells: mechanisms and therapeutic potential for inflammatory diseases” (click pdf)

This paper was overly long at 127 pages, so I focused on the later sections. None of these treatments are currently ready for clinical trials.

I also didn’t mention specific flavonoids as Nrf2 activators. It’s beyond a reviewer’s task to rank Nrf2 activators, and a study’s researchers seldom address why they used a poorly-activating flavonoid instead of a higher-ranked natural plant compound such as sulforaphane.