Eat broccoli sprouts to inhibit β-amyloid

This 2020 lab study investigated sulforaphane’s effects on an Alzheimer’s disease enzyme:

“BACE1 is the rate-limiting enzyme responsible for the production of Aβ [amyloid-beta] from APP [amyloid precursor protein]. Both the expression level and activity of this enzyme are aberrantly elevated in the brains of patients with AD.

Sulforaphane exhibited six times more potent activity against BACE1 compared to well-known positive controls including resveratrol and quercetin. Sulforaphane presented selective and non-competitive BACE1 inhibitory activity with low off-target inhibition.

Molecular docking simulation was used to analyze whether the compound can reach the target enzyme to produce the biological effect safely and interact with the targeted sites.

The blood–brain barrier (BBB) is constituted by neurovascular units that contain endothelial cells. A previous study reported that gavage administration of sulforaphane penetrated BBB in its intact structure and accumulated in brain tissues with a maximum increase and disappearance after 15 min and 2 h, respectively.” ” Discovery of Sulforaphane as a Potent BACE1 Inhibitor Based on Kinetics and Computational Studies”

Nano-sulforaphane vs. barbecue chemicals

This 2020 chicken study investigated the capability of nano-sulforaphane to protect embryonic survival and neurogenesis from a barbecued meat chemical:

“Common teratogenic [of, relating to, or causing malformations of an embryo or a fetus] factors related to the development of the nervous system, such as alcohol consumption and smoking, have attracted wide attention. Teratogenic factors such as PhIP, the most abundant amine produced in common cooking procedures, can affect early embryonic development, leading to abnormal development of the nervous system.

Nano-sized medicine, in comparison with conventional medicine, leads to increased active concentrations and bioavailability. Both PhIP and nanoparticles can cross the placental barrier and enter the fetus from the external environment.

Chick embryos (100 per group) were incubated with 0.1% DMSO (Control); 20μM, 100μM, 200μM, or 300μM PhIP; or 200μM PhIP + 5μM Nano-SFN [sulforaphane] for 36 h:

  • Mortality rates were 0% for the Control, 8% with 20μM PhIP, 20% with 100μM PhIP, 53% with 200μM PhIP, 85% with 300μM PhIP, and 7% with 200μM PhIP + 5μM Nano-SFN.
  • Neural tube malformation rates [for the remaining live embryos] were 0% for the Control, 5% with 20μM PhIP, 14% with 100μM PhIP, 36% with 200μM PhIP, 14% with 300μM PhIP, and 6% with 200μM PhIP + 5μM Nano-SFN.

Women at the early stage of pregnancy should avoid barbecue. Instead, increase intake amount of cruciferous vegetables, which benefits fetal neural development.” “Nano-sulforaphane attenuates PhIP-induced early abnormal embryonic neuro-development” (not freely available)


Dietary contexts matter

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

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

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

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

DHA exhibits differential influence on epigenetic loci, genes, pathways, and metabolic and cognitive phenotypes under different dietary contexts.” “Multi‐tissue Multi‐omics Nutrigenomics Indicates Context‐specific Effects of DHA on Rat Brain” (not freely available)

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

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

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

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

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

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

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

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

binary isobologram

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

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

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

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

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

Diving for breakfast

Rub some broccoli sprouts on it

This 2020 human/rodent study investigated treating and preventing skin photodamage with sulforaphane:

“Alterations in NRF2 signaling have been implicated in aging and stress-induced skin pigmentation disorders in the skin and hair follicles. NRF2 signaling regulates transcriptional programs involved in adaption and survival of cells in the setting of oxidative stress, and oxidative stress occurs in the setting of photodamage.

[1st human experiment with 14 subjects] Expression levels of NRF2 and its target heme-oxygenase-1 (HO-1) were evaluated by immunofluorescence (IF) in skin biopsies. Expression of NRF2 and HO-1 was significantly reduced in skin from individuals > 45 years old.

[2nd human experiment with 7 different subjects] The left arm was chosen for treatment with BSE [broccoli sprout extract], as there is typically more photodamage on the left arm due to chronic sun exposure through the car window while driving in the US. A photoprotected area of skin on an upper inner arm was also treated.

Expression of total NRF2 and phosphorylated NRF2 (NRF2-P) by IF microscopy was detected at low baseline levels in photoprotected skin, suggesting some activity of the pathway, whereas the expression of total NRF2 and NRF2-P was undetectable in untreated photoexposed skin (Un). There was significantly elevated IF expression and fold change of IF signal of NRF2 and especially NRF2-P in SF [sulforaphane]-treated skin compared with Un skin in most individuals.

There was no evidence of increased total NRF2 or NRF2-P expression in SF-treated photoexposed skin in 2 individuals. There was also no significant improvement in mottled hyperpigmentation or difference in melanin deposition following SF treatment.

[Six mouse confirmation/exploratory studies] SF is known to have several non-NRF2–mediated targets, such as NF-κB and AP-1. However, our findings suggest that negative regulation of UV-mediated hyperpigmentation observed following SF treatment is occurring in an NRF2-dependent fashion:

  • UVB+SF treatment resulted in more than a 50% decrease in skin pigmentation and melanin deposition, indicating that SF could prevent UVB-induced skin pigmentation.
  • The therapeutic effect of SF on reducing UVB-induced skin pigmentation was dependent on keratinocyte-intrinsic IL-6 receptor α (IL-6Rα) signaling that upregulated NRF2, which led to inhibition of melanogenesis.

Our results provide direct in vivo evidence of how NRF2 is involved in response to oxidative stress associated with photodamage and chronic UV exposure. Treatment of human or mouse skin hyperpigmentation with SF provided the proof of concept for targeting the NRF2 pathway as a therapeutic intervention.” “Pathogenic and therapeutic role for NRF2 signaling in ultraviolet light–induced skin pigmentation”

Didn’t understand the 2nd experiment’s human dose of 5 nM sulforaphane. The lead author’s cited 2017 study Randomized, split-body, single-blinded clinical trial of topical broccoli sprout extract: Assessing the feasibility of its use in keratin-based disorders used “500 nmol of sulforaphane/mL.” Unless my math is off, the current study and previous study’s doses weren’t equivalent since 1 nM = 0.001 nmol/mL.

I’d like to know more about subjects who didn’t respond to topical sulforaphane treatment. What happened in their lives to make them dead to an evolutionarily-selected antioxidant and anti-inflammatory signaling pathway that influences many other internal environmental signals? Guess we’ll have to wait for:

“Further clinical studies with an increased number of human subjects, longer treatment regimens, and additional body sites are needed to further assess the long-term effects of NRF2 activation on photoaging.”

See Eat broccoli sprouts for your skin! and Eat broccoli sprouts for your hair! for similar studies.

Owl before sunrise

Week 28 of Changing to a youthful phenotype with broccoli sprouts

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

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

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

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

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

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

sulforaphane peak plasma

So we’re patient.

A research train wreck

I try to highlight research that advances science. Please humor a momentary break.

This 2020 study Effects of cooking methods on total isothiocyanate yield from cruciferous vegetables simulated microwaving broccoli to 210° C (410° F). These researchers knew or should have known that myrosinase inactivates at moderate temperatures, given studies published last century such as this with its “Thermal inactivation proceeded in the temperature range 30−60° C” finding. Without an active enzyme, no isothiocyanates are produced from cooking broccoli.

Incredibly, these researchers proved they knew their study detracted from science by citing Microwave broccoli to increase sulforaphane levels. That study found destructive effects on sulforaphane at temperatures above 60° C (140° F):


The sulforaphane (SFR) amount at HL70° on the right (broccoli heated to 70° C with a 950 W microwave operated on full power) was significantly less than uncooked broccoli (control) on the left!

“This work was supported by the National Cancer Institute.”

I haven’t found words to correspond with the coauthors. Egregious errors speak for themselves.

Eat broccoli sprouts to pivot your internal environment’s signals

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

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

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

No biomarkers excel at defining pharmacodynamic actions in this setting.

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

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

It is equally evident that other modes of action contribute to the molecular responses to SFN in animals and humans. Such polypharmacy may well contribute to the efficacy of the agent in disease prevention and mitigation, but obfuscates the value of specific pharmacodynamic biomarkers in the clinical development and evaluation of SFN.” “Current Landscape of NRF2 Biomarkers in Clinical Trials”

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

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

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

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

DNA methylation epigenetic clocks capture aspects of biological age.”

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

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

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

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

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

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

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

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

Human relevance of rodent sulforaphane studies

After reading through findings of several dozen rodent studies this evening, I thought it would be worthwhile to revisit analysis of human relevance provided by one paper of How much sulforaphane is suitable for healthy people?

“Comparisons of published oral doses of sulforaphane administered to mice or rats and sulforaphane (tablets or sulforaphane-rich broccoli preparations) or glucoraphanin-rich broccoli preparations administered to humans.

The allometric scaling of the murine doses uses the correction factor of 0.081 and those for rat doses 0.162. Human doses were based on an estimate of 70 kg body weights in each study.”

A confession followed:

“Animal studies have not delivered all that might be expected of them. Pre-clinical experimentalists have not thought carefully about the selection of dose (or route) and its relevance to clinical utility.

Over two-thirds of the animal studies have used doses that exceed the highest (and bordering on intolerable) doses of sulforaphane used in humans.

Few studies have included a dose-response. The greater than 4-log spread of doses used in mice appears to be driven by needs for effect reporting in publications rather than optimization of translational science.

Authors of this review have contributed to this dose skewing.”

Let’s narrow this graphic to a human-relevant range:


48 of the 114 rodent study doses were in an allometric range applicable to humans.

Clinically relevant sulforaphane human doses start at a 100 µmol amount (17.73 mg). The graphic normalized human weights to 70 kg, so 100 µmol / 70 kg is 1.43 µmol / kg. Eyeballing the graphic, 43 of the 114 rodent study doses were in an allometric range applicable to human clinical doses.

But only three of the human sulforaphane study doses were above 4 µmol / kg. This indicator of the mentioned “intolerable doses” will limit clinically relevant oral doses to no more than 17.73 mg x (4 / 1.43) ≈ 50 mg in one serving.

Reviewing clinical trials of broccoli sprouts and their compounds described a sulforaphane study with doses above 4 µmol / kg:

“They proposed the intake of 15 capsules of broccoli sprouts at a time, giving 90 mg [508 µmol, 7.26 µmol / kg] of SFN and 180 mg of glucoraphanin, a never before tested dosage, which was established because of the poor life expectancy of the patients and the aggressive characteristics of this type of cancer.

Secondary effects of the chemotherapy, the lack of appetite, nausea, vomits, diarrhea, mouth sores, etc., were factors that made it very difficult for the patients to intake 15 pills at once, as the study initially planned.

Progression of the pancreatic cancer and the GI symptomatology led to a high rate of drop-off of:

  • 72% in the treatment group; and
  • 55% abandonment in the control group!

Therefore, the results were not significant.”

Our model clinical trial Effects of long-term consumption of broccoli sprouts on inflammatory markers in overweight subjects calculated subjects’ mean weight in Table 1 as “85.8 ± 16.7 kg.” Its average glucoraphanin dose per kg body weight was 117 μmol / 85.8 kg = 1.36 μmol / kg.

Per Estimating daily consumption of broccoli sprout compounds, my twice-a-day consumption of a total 131 grams microwaved broccoli sprouts represents a worst-case 52 mg sulforaphane daily intake. This is ≈ 3 µmol / kg per day, the graphic’s second-largest sulforaphane amount cluster. Half that per serving.

Only 8% of the rodent studies were in a sulforaphane range that was both:

  • Clinically relevant to humans as a lower boundary (1.43 µmol / kg); and
  • Tolerable to humans as an upper boundary (4 µmol / kg).

human-rodent clinically relevant tolerable dosages

The main purpose of animal studies is to help humans. Which researchers conducted sulforaphane studies that could actually help humans?

Natural sources of melatonin

This 2020 review subject was melatonin:

“The emergence of naturally occurring melatonin and its isomers in fermented foods has opened an exciting new research area. Melatonin is a hormone, an indolamine that predominantly appears in plants, microorganisms, and mammals.

The precursor of this molecule is solely the amino acid L‐tryptophan. Melatonin ensures a circadian and seasonal signal to vertebrate organisms; it is synthesized through a cascade of enzymatic reactions producing melatonin from serotonin in its final phases. The synthesis of melatonin is observed in almost all organs.

One melatonin molecule has the capacity to scavenge up to 10 ROS versus the other antioxidants that scavenge 1 or even less ROS. Melatonin antioxidant properties are accomplished with the indole ring that stimulates enzyme production (i.e., superoxide dismutase (SOD), glutathione‐peroxidase (Gpx), and catalase (CAT)), which mitigate free radicals to less toxic substances.

In addition to antioxidant properties, it plays a fundamental role in the modulation of various physiological functions, including circadian rhythmicity, bone integrity, and functionalization of the human reproductive system.

The presence of melatonin and its isomers is not exclusive for grapes and grape‐derived products. Other fruits such as sweet and sour cherries and fermented juices of orange and pomegranate may be also of interest.” “Naturally occurring melatonin: Sources and possible ways of its biosynthesis”

Grow a Victory Garden in mason jars

I tried a new process with success during the past 27th week of eating broccoli sprouts every day. My son suggested that mason jars with strainer lids would streamline the broccoli sprout production process. He was right, and then some.

I start a new batch every twelve hours. The left jar contained soaking seeds.

Here are thirteen measurements from this week compared with weights of a similar period last month. Starting amounts of broccoli seeds were all 10.7 grams, batches were rinsed three times each day on a 12 hour-6 hour-6 hour schedule, and weights taken at the 72-hour point:

Higher weights with less variation were reflected in broccoli sprout sizes. Few sprouts grew over one inch in three days when in bowls, but look at them now:

Larger broccoli sprouts taste better, too. After microwaving them on 1000W full power for 35 seconds to ≤ 60°C (140°F), I wait five minutes to allow further myrosinase hydrolization of glucoraphanin and other glucosinolates into sulforaphane and other healthy compounds.

Further changes from what’s outlined in Step 5 of Grow a broccoli sprouts Victory Garden today! include:

  • I don’t shape batches anymore. I do fill each pint jar to the top and let it sit for five minutes in order to soak all seeds and sprouts.
  • I leave cooking water in after microwaving rather than straining it out. Although some leaching of water-soluble glucoraphanin may occur, I drink that water anyway.
  • I don’t mix in mustard, sauerkraut, or other flavorings. Still trying to make unsalted sauerkraut that tastes good.

I mistakenly pasted in a 9/10 p.m. value of 69.9 grams instead of its a.m. value of 66.0. Correcting it in my workbook changed the sample average from 68.8 g to 68.5 g. The correction didn’t change either the sample’s 4.9 g standard deviation value or the null hypothesis’ failed-test 0.0258 p-value.

This post is my one and only experiment with using the “new” retro Word Press block editor to start a new blog post. 😦 Word Press management knew this non-productive change was a non-starter, but foisted it on their users for their own convenience. 😦

They require me – along with hundreds of thousands of Word Press users – to edit blog posts with it. 😦 If retro is better, why don’t we all just go back eight decades to the most primitive text editor?