- What is Sulforaphane? + Foods (Kale, Broccoli Sprouts)
- What are Sulforaphane and Broccoli Sprouts?
- Prostate Cancer
- Research in Other Cancers
- Possible Mechanisms
- Sulforaphane Side Effects
- 1) Genome Stability
- 2) Liver Toxicity
- Food Sources
- Genetics And Sulforaphane Metabolism
- SNPs in the GSTM1 gene
- SNPs in the GSTT1 gene
- SNPs in the GSTP1 gene
- As an Indirect Antioxidant:
- Gene Expression:
- Weight Management:
- Further Reading
- The Best 12 Foods to Reverse Aging with Sulforaphane
- Reverse Aging with Sulforaphane
- What is Sulforaphane?
- 1. Slows Aging
- 2. Stops Inflammation
- 3. Fights Cancer
- 4. Protects Your Brain
- 5. Protects Your Heart
- 6. Sulforaphane Detoxifies
- 7. Keeps You Thin
- 8. Reverses Diabetes
- 9. Lowers Cholesterol
- 10. Treats Depression and Anxiety
- Does Sulforaphane Have Any Side Effects?
- How Do You Maximize Sulforaphane from Your Vegetables?
- 1. Broccoli Sprouts
- 2. Broccoli
- 3. Cauliflower
- 4. Kale
- Practical Tips
- Broccoli and why it isn’t enough
- Quick fix: add natural myrosinase
- Alternative: Use Supplements
- Health Dangers of Cruciferous Vegetables
- Health Dangers of Cruciferous Vegetables – What are they?
- Health Dangers of Cruciferous Vegetables – “Broccoli Bomb”
- Sulforaphane and Cancer
- I see it through another lense though
- Health Dangers of Cruciferous Vegetables – Thyroid Health
- Health Dangers of Cruciferous Vegetables – What to do
What is Sulforaphane? + Foods (Kale, Broccoli Sprouts)
Why should you eat your greens? Sulforaphane, an active compound in broccoli and other Brassica vegetables, may help prevent prostate cancer from recurring. Read on to learn about this beneficial compound and where to get it in your diet.
What are Sulforaphane and Broccoli Sprouts?
Sulforaphane (SFN) is an isothiocyanate, a sulfur-containing organic compound [1, 2].
It is found in cruciferous vegetables such as broccoli, cabbage, cauliflower, Brussels sprouts, and kale [1, 2].
Sulforaphane is produced when glucoraphanin comes into contact with the enzyme myrosinase, contained within the same cells but in different compartments [1, 3].
For example, cutting, chewing, or otherwise disrupting the broccoli plant cells initiates the production of sulforaphane. Compared to the stable glucoraphanin, sulforaphane begins degrading soon after production .
Three-day-old sprouts of certain cruciferous vegetables contain 10 to 100 times higher concentrations of glucoraphanin than in mature plants .
Levels of glucoraphanin and sulforaphane are highest in broccoli sprouts .
Sulforaphane has antioxidant, antimicrobial, anticancer, anti-inflammatory, anti-aging, neuroprotective, and anti-diabetic properties .
Sulforaphane also protects against cardiovascular and neurodegenerative diseases .
Apart from sulforaphane, broccoli sprouts contain many other bioactive, health-promoting compounds, such as gallic, chlorogenic, ferulic, sinapinic, benzoic and salicylic acids, quercetin, kaempferol, and vitamin C .
To learn about the many potential benefits of sulforaphane and sulforaphane-rich vegetables, check out this post.
Sulforaphane (in the form of broccoli sprout extract) boasts some relatively strong clinical evidence for a role in the prevention of prostate cancer and management strategies for preventing recurrence of prostate cancer.
In multiple clinical studies, men with recurrent prostate cancer who took 60 mg of sulforaphane per day had less prostate specific antigen (PSA, a marker used to measure prostate cancer progression) than those who did not take sulforaphane [6, 7].
That being said, the FDA has not approved sulforaphane for the prevention of prostate cancer recurrence. Talk to your doctor before supplementing.
Research in Other Cancers
While studies have advanced the furthest for sulforaphane in prostate cancer, it is also under investigation for possible action against other types of cancer. Sulforaphane is considered a promising compound for a few reasons; not least of these is that people who eat sulforaphane-rich Brassica vegetables are significantly less ly to develop cancer [8, 9].
Three to five servings of Brassicas per week are associated with a 30% to 40% decline in the incidence of cancer compared to people who don’t eat these vegetables .
Subjects who consumed at least one portion of cruciferous vegetables per week were less ly to develop oral cavity, pharynx, esophageal, colorectal, breast, and kidney cancers .
Researchers are also investigating the potential of sulforaphane against glioblastoma, thyroid, prostate, mammary, tongue, and lung cancer in animals [10, 11, 12, 8, 13, 14].
Broccoli sprouts also significantly and dose-dependently inhibited bladder cancer development in rats, and UV-radiation-induced skin cancer development in mice [15, 16].
- SFN inhibits phase I enzymes that can activate pro-carcinogens 
- SFN induces phase II enzymes that are responsible for eliminating chemicals that damage DNA 
- SFN changes gene activation/deactivation, and causes demethylation, thereby restoring the activity of important tumor-suppressing and cell-cycle controlling genes 
- Sulforaphane induces cancer cell death 
- Sulforaphane inhibits the NF-κB pathway, thus reducing inflammation 
- Sulforaphane induces cell cycle arrest, and thereby inhibits cancer cell proliferation 
Apart from being effective in its own right, sulforaphane may also enhance the efficacy of anti-cancer drugs including cisplatin, gemcitabine, doxorubicin, and 5-fluorouracil, toward pancreatic and prostate cancer cells, while limiting their toxicity to normal cells .
However, although sulforaphane was found to be safe and effective in several studies, it was not effective in two clinical trials [7, 17].
Additional studies are still required before sulforaphane could be incorporated into conventional cancer therapies. Talk to your doctor before attempting to use sulforaphane and sulforaphane-rich foods for any medical purpose, let alone cancer prevention or treatment.
Sulforaphane Side Effects
Sulforaphane is considered safe when consumed in the amounts available in broccoli and other greens, and very few side effects have been observed in clinical trials of broccoli sprouts, their extracts, or purified sulforaphane. However, supplements are not standardized, and we do not have sufficient data to determine the safety of long-term sulforaphane use. Talk to your doctor to avoid adverse effects or unexpected interactions.
1) Genome Stability
Sulforaphane appears to increase the activation of many beneficial genes, including tumor suppressor genes. However, sulforaphane may also activate long terminal repeats (LTRs), DNA sequences found within our genome that impair genome stability and cause mutations .
Consumption of broccoli sprouts by human volunteers caused a 10-fold increase in LTR activation in white blood cells. These effects are transient, and it remains to be determined whether they are biologically meaningful .
Other studies on human volunteers recorded no abnormal events related to broccoli sprout consumption .
Genotoxic effects were observed in unpublished studies with pigs fed with 600 g of raw broccoli for 12 days. These pigs had an increase in DNA strand breaks by 21% in the colon .
Also, after feeding raw or steamed broccoli to mice and rats, an increase in DNA adducts (cancer-causing chemicals binding to DNA) was observed .
However, all these effects in animals were observed for mature broccoli plant consumption. An additional benefit of broccoli sprouts is that they contain negligible quantities of indole glucosinolates, which predominate in the mature vegetable, and may give rise to degradation products (e.g., indole-3-carbinol). This may enhance tumorigenesis .
2) Liver Toxicity
There is a single case report of liver toxicity after drinking large amounts of broccoli juice for 4 weeks (800 ml/day). Transaminases, aspartate aminotransferase, and c-glutamyltrans-peptidase were elevated but decreased to normal within 15 days .
This was also caused by consuming the mature plant; the contribution of sulforaphane is unknown. Until we know more, caution is advised.
The amount of sulforaphane (glucoraphanin) can vary widely in vegetables .
Broccoli is not the only cruciferous vegetable which has SFN, but it yields the highest amounts, with glucoraphanin content around 75% of total glucosinolates .
Furthermore, 3-day-old broccoli sprouts contain 10 to 100 times higher levels of glucoraphanin than does a mature broccoli [22, 23].
Do not confuse broccoli sprouts with Brussels sprouts (though Brussels sprouts also contain sulforaphane) .
Vegetables with high sulforaphane content include [24, 25]:
- Broccoli sprouts
- Brussels sprouts
Genetics And Sulforaphane Metabolism
GSTs are a large family of glutathione conjugating enzymes, which attach glutathione to the substance that needs to be detoxified the body. Three of them, GSTM1, GSTP1, and GSTT1 have been implicated in the metabolism of isothiocyanates, and sulforaphane in particular .
SNPs in the GSTM1 gene
Null mutations in GSTM1 result in the absence of a functional enzyme. The frequency of the GSTM1-null variant is estimated to be between 27 and 53% in human populations .
Individuals with GSTM1-null mutations may benefit more from SFN due to the decreased degradation of SFN, which therefore increases exposure .
However, several other studies suggest otherwise. In these studies, GSTM1-positive individuals benefited more from either broccoli or cruciferous vegetable consumption compared to GSTM1-null individuals. GSTM1-null carriers excrete more SFN and SFN-metabolites, and excretion is faster .
SNPs in the GSTT1 gene
Null mutations in the GSTT1 gene result in the absence of a functional enzyme. The frequency of the GSTT1-null variation has been estimated to be between 10 and 21% for Caucasian populations and as high as 64% for Asian populations .
Broccoli sprouts are more effective in detoxification when GSTT1-positive carriers are exposed to airborne pollution compared to the null carriers .
SNPs in the GSTP1 gene
As an Indirect Antioxidant:
- SFN activates Nrf2 by binding Keap1 [8, 28]
- SFN reacts with Keap1, thereby releasing Nrf2 from Keap1 binding 
- SFN promotes ARE-driven gene expression [8, 28]
- SFN increases other phase II enzymes: NQO1, GSTA1, and HO-1 [30, 31, 32, 33]
- SFN inhibits phase I enzymes CYP1A1, CYP1A2, CYP1B1, CYP2B2, and CYP3A4 [22, 8]
- SFN blocks SXR 
- SFN inhibits NfkB [34, 8, 35]
- SFN decreases TNF-α, NLRP3, IL-1β, IL-18, IFN-gamma and IL6 [36, 37, 38, 39, 40, 41]
- SFN increases IL-10, IL-4, Arg1, and YM-1 [36, 41, 33, 42]
- SFN decreases NO, iNOS and COX-2 [37, 41, 43]
- SFN silences Th17/Th1 responses [44, 33]
- SFN decreases IL-17 [39, 44]
- SFN decreases TGF-β/Smad 
- SFN decreases IL-23 and IL-12 expression 
- SFN decreases MMP-9 [33, 43]
- SFN decreases LDH and PGE2 
- DNA hypermethylation can inhibit tumor suppressor genes and genes involved in cell cycle regulation and apoptosis (cell death). DNA methyltransferases (DNMTs) methylate DNA, and an overexpression of DNMTs is observed in a number of cancers, including leukemia, gastric, lung, and prostate cancer [8, 46]
- Sulforaphane inhibits DNMT1 and DNMT3A 
- SFN is one of the most potent (histone deacetylase) HDAC inhibitors found to date 
- SFN inhibits HDAC1, HDAC2, HDAC3, and HDAC4 [47, 8]
- SFN decreases miR-21 and TERT 
- SFN‐induced browning of white adipocytes (fat cells) 
- SFN decreases PPARγ and C/EBPα 
- SFN increases AMPK 
- 7+ Sulforaphane Benefits (Broccoli Sprouts or Supplements)
The Best 12 Foods to Reverse Aging with Sulforaphane
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Reverse Aging with Sulforaphane
Could sulforaphane be the best superfood you have never heard of? ��If so, that would make broccoli sprouts the healthiest food on this planet. ��In this article, I’ll share the science behind why sulforaphane may be the best way to reverse and prevent almost every medical condition. ��I’ll also reveal the best 12 foods to reverse aging with sulforaphane.
What is Sulforaphane?
Sulforaphane is a sulfur-containing food molecule that reverses aging, stops inflammation, kills cancer, protects the brain, and puts an end to cardiovascular disease.
��While sulforaphane is found naturally in cruciferous vegetables, these vegetables must be prepared and eaten in the right way to maximize the bioavailability of sulforaphane.
��And it is this special preparation that explains why broccoli sprouts have so much more sulforaphane than all of the other cruciferous vegetables combined.
1. Slows Aging
Sulforaphane turns on your genes which make Nrf2. ��Studies show that Nrf2 is the master protein in the body to slow aging by activating whatever longevity genes you may have.
While you have probably never heard of Nrf2, there have now been more than 5,500 scientific studies published on Nrf2. ��What we do know is that Nrf2 prevents the cells in your body from growing old by protecting them from inflammation, free radicals, and the many other things that wear your cells out over time.
2. Stops Inflammation
Chronic over stimulation of the immune system causes inflammation. ��Chronic inflammation in turn causes rusting of our bodies.
Inflammation that is never turned off is one of the root causes of premature aging, autoimmune disease, arthritis, cancer, dementia, and heart disease. ��Through activation of Nrf2, studies show that sulforaphane stops inflammation and recalibrates the immune system to function properly again.
3. Fights Cancer
Cancer is perhaps the most feared of all human conditions. ��And when it comes to cancer fighting foods, sulforaphane seems to be the best.
People eating the most cruciferous vegetables have long been known to have very��low rates of cancer. ��In studies, sulforaphane is incredibly effective in stopping most forms of cancer in animals.
how effective sulforaphane is in destroying cancer in the laboratory, researchers are now studying it in humans. ��For example, there are now 12 studies assessing the cancer fighting effects of sulforaphane in humans.
4. Protects Your Brain
No one wants to lose their memories. ��As I discussed in blog number 81, BDNF or brain derived neurotrophic factor, is the most important protein to have around in your body if you want a sharp brain throughout your life.
Fortunately, studies show that sulforaphane also boosts BDNF. ��Perhaps this boost in BDNF helps to explain why studies of diabetic rats, who are known to quickly develop dementia, can preserve their memories with sulforaphane.
5. Protects Your Heart
It has often been said that you are only as old as your arteries. ��Indeed, your biological age is directly linked to how much plaque is in your arteries. ��If you can keep the plaque out, your body will stay young.
When it comes to staying young and preventing cardiovascular disease, you need more sulforaphane. ��As with cancer, many studies have reported that those people eating the most sulforaphane from cruciferous vegetables live longer and are much less ly to get heart disease.
Specifically, sulforaphane prevents atherosclerosis or plaque build up. ��For example, in one interesting study researchers pumped rabbits full of the highest cholesterol containing food they could find. ��Despite a diet literally off the charts in cholesterol, the rabbits who were also fed sulforaphane foods didn’t get hardening of their arteries.
6. Sulforaphane Detoxifies
If you do a quick Google search you will find many ads for ways you can detoxify your body. ��Sadly, most of these are scams.
If you really want to detoxify your body then you need sulforaphane. For example, sulforaphane has been shown in studies to detoxify pesticides on our food.
For those of you who barbecued meat, but don’t want to increase your risk of cancer from the heterocyclic amines that form when you cook meat, eat sulforaphane foods with your meat.��Studies show that sulforaphane can block up to 60% of these heterocyclic amines cancer causing compounds.
Studies also show that sulforaphane can detoxify the polluted air we breath into our bodies. ��In fact, one interesting study from a very polluted city in China showed that broccoli sprout juice detoxified the chemicals found in polluted air. ��Specifically, broccoli sprout juice detoxified 61% of benzene, which is a known carcinogen from air pollution.
7. Keeps You Thin
If you want to gain weight really fast, just eat the Standard American Diet (SAD). ��The Standard American Diet makes it almost impossible for anyone to maintain a healthy weight. ��This is because all of the sugars and processed carbohydrates screw up countless metabolic and hormonal pathways in your body.
In an interesting study, researchers put mice on the Standard American Diet. ��Not only did these mice quickly become very obese, they also became insulin resistant, had sky high cholesterol levels, and developed atherosclerosis.
Where this study gets interesting is that sulforaphane blocked the effects of the Standard American Diet. ��In other words, hunger hormone levels dropped so the mice weren’t always so hungry and lost weight. ��Insulin metabolism normalized. ��Blood pressure and cholesterol levels dropped and atherosclerosis was reversed.
8. Reverses Diabetes
Diabetes, or high blood sugar levels, is one of the fastest ways to age your arteries. ��Exciting new research is showing that sulforaphane may ultimately become the best diabetes drug.
Indeed, in a recently published study, researchers from the University of Gothenburg in Sweden enrolled 97 obese people with type 2 diabetes. ��They then randomized these people to either broccoli sprouts or placebo.
After just 12 weeks, those people randomized to broccoli sprouts had blood sugar readings 10% lower than those randomized to a placebo. ��Probably the best part of this study is that researchers didn’t see all of the side effects that you would expect to see from the typical diabetes drug.
9. Lowers Cholesterol
Across the world, studies show that the longest lived groups of people all have low cholesterol levels. ��This is probably because when cholesterol levels are low, aging of your arteries slows to a crawl.
While few people want to take a statin drug to reduce high cholesterol, one possible alternative could be broccoli sprouts. ��Indeed, in one study broccoli sprouts reduced LDL or bad cholesterol by 7%.
Of course, if you have already been prescribed a statin don’t stop it. ��In fact, don’t ever act on anything I share in an article without talking to your physician first.
10. Treats Depression and Anxiety
More and more studies��are pointing to inflammation as the cause of depression, anxiety, and other mental health conditions. ��As sulforaphane is a powerful anti-inflammatory compound, then one would expect sulforaphane to help depression and anxiety.
While there aren’t any good studies showing that sulforaphane treats depression and anxiety in humans, it certainly seems to help mice with their depression and anxiety. ��Indeed, studies show that by blocking excessive inflammation in mice, sulforaphane makes mice less stressed and happier.
Does Sulforaphane Have Any Side Effects?
Fortunately, I have never seen any side effects from eating too many cruciferous vegetables in my cardiology practice. ��However, just because I have never seen any doesn’t mean it couldn’t happen.
For example, there is a theoretical risk of developing a thyroid goiter from eating too many crucriferous vegetables. ��Despite this theoretical risk, I could find no studies showing that this happens in people who are eating a healthy diet which includes adequate amounts of iodine for optimal thyroid function.
Other possible side effects reported in the medical literature include DNA disruption from massive quantities of broccoli sprouts. ��wise, there was a case report of liver toxicity from drinking huge amounts of broccoli sprout juice.
How Do You Maximize Sulforaphane from Your Vegetables?
Cutting or chewing cruciferous vegetables unlocks sulforaphane. ��However, cooking cruciferous vegetables destroys sulforaphane. ��Thus, to unlock sulforaphane it is best to eat cruciferous vegetables raw.
As you undoubtedly have learned by making it this far in the article, raw cruciferous vegetables are the key to unlocking sulforaphane. ��However, when it comes to sulforaphane, not all cruciferous vegetables are created equally. ��Below, are the top foods for sulforaphane.
1. Broccoli Sprouts
Of all the foods studied, broccoli sprouts have the highest amount of sulforaphane. ��Indeed, studies show that broccoli sprouts have anywhere from 10 to 100 times the amount of sulforaphane than do the mature broccoli plants.
Fortunately, it is easy and very inexpensive to sprout your own broccoli at home. ��Most people just do it inside of their kitchen window.
For those of you who prefer not to sprout your own broccoli, there are other options. ��For example, our local Whole Foods grocery store sells broccoli sprouts.
While mature broccoli lacks the mega dose of sulforaphane that the sprouts do, it still has a lot of sulforaphane. ��In fact, of the cruciferous vegetables, broccoli and cauliflower pack the most.
As with broccoli sprouts, I was also surprised to learn that cauliflower sprouts are also high in sulforaphane. ��However, as no one that I know eats cauliflower sprouts, just sticking to the adult form will still give you a good dose of sulforaphane.
Kale is another one of my favorite foods that I eat on most days. ��Nutrient for nutrient, it is hard to find a food that packs in more than kale.
thousands of medical studies, sulforaphane may be the best superfood. ��As these studies are so convincing, I make it a practice to include several cups of raw broccoli, kale, or cauliflower into my diet every day. ��This practice fits well with the many studies showing that people eating cruciferous vegetables live longer and have less cancer and heart disease.
As we really don’t know what the upper limit of sulforaphane is that we can safely enjoy, I don’t eat broccoli sprouts that often. ��This is because I haven’t seen any long-term studies of people getting mega doses of sulforaphane from broccoli sprouts. ��Until these studies are done, I’ll play it safe and reserve broccoli sprouts as an occasional treat.
What is your take on broccoli sprouts? ��I would love to hear from you. ��Please leave your thoughts and questions below.
As always, I’ll try my best to answer every question as quickly as I can. ��If you want to learn more about how food choices prevent disease and promote longevity, please be sure to read our new book, The Longevity Plan, subscribe to our free weekly newsletter, or listen to our podcast.
Disclaimer Policy: This website is intended to give general information and does not provide medical advice. This website does not create a doctor-patient relationship between you and Dr. John Day.
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Broccoli and why it isn’t enough
In the first post of the sulforaphane series, we covered that consuming sulforaphane can lower inflammation. Now let’s talk about why eating tons of cooked broccoli may have zero effect.
Ok, so I told a white lie in the first post: Cruciferous vegetables such as broccoli, cauliflower and cabbage don’t contain actual sulforaphane.
What they do contain however is the precursor of sulphoraphane. It’s called glucoraphanin, and it accumulates in the vegetable’s florets and leaves. Only on consumption does it turn into sulforaphane.
This requires the help of the enzyme myrosinase.
This enzyme is turned on when the raw vegetable is crushed, chopped or chewed. It is usually delivered with the vegetable but unfortunately is often denatured when cooked.
When an enzyme is denatured, it can no longer do its job because it has lost its structure. Think of a paperclip that is bent open.
You can still say it is a paperclip, but it can no longer perform the function of holding papers together. That’s what happens to enzymes when they become denatured.
Does that mean, I’ll have to eat my vegetables raw from now on? No. Luckily, there are other enzymes found in a healthy colon, which can partly take over the job of myrosinase.
Additionally, lightly steaming cruciferous vegetables will allow the myrosinase to keep functioning, but it means your vegetables will be very crunchy.
If you your vegetables soft you have to find a different source of myrosinase. Here are your options:
Quick fix: add natural myrosinase
Simply sprinkle some broccoli sprouts, mustard seeds, horseradish, daikon or wasabi over your cooked vegetables. These have so much myrosinase that they manage to turn most of the glucoraphanin in your cooked cruciferous vegetables into sulforaphane.
Unfortunately, the amount of glucoraphanin in mature broccoli varies quite widely. That’s why broccoli sprouts—which contain 20-100 times more glucoraphanin than mature broccoli—are now considered the “gold standard” for studying sulforaphane and its health effects.1
Glucoraphanin Yield from raw cruciferous vegetables2
(Numbers are not exclusively glucoraphanin, but isothiocyanates in total, which do not all turn into sulforaphane.)
|Broccoli||6.9 (2.6 – 18.1)|
|Cabbage||31.7 (0.5 – 77.9)|
|Cauliflower||1.5 (0.7 – 2.7)|
|Brussels sprout||9.6 (0.6 – 21.1)|
|Kale||3.7 (0.4 – 12.9)|
|Mustard Green||61.3 (0.4 – 137.9)|
Alternative: Use Supplements
There are some supplements that have synthesized sulforaphane, but these are not very stable and should be refrigerated. There are two on the market that have been investigated in the scientific community. Note, we’re not affiliated with either of them.
One is a stabilized form of sulforaphane called Prostaphane containing the equivalent of 100 g of raw broccoli per tablet. It needs to be refrigerated at all times and is only available in France and neighboring countries at the moment.
3 The other contains glucoraphanin and myrosinase and is called Avmacol, unfortunately it’s currently not available outside the US.
In order to understand how sulforaphane actually works once we have it in our bodies, we need to take a short trip down its biochemical pathway. Sulforaphane can activate the transcription factor Nrf2. A transcription factor is something that can influence which genes are transcribed from DNA into messenger RNA, called mRNA. mRNA moves the nucleus and can be translated into proteins.
MND Research Blog
Proteins the ones found in egg white or meat? Yes, these foods contain proteins, but the proteins we are talking about are the ones that do most of the heavy lifting inside the cell.
They make sure things get transported in and the cell, make reactions happen and make replication possible. Another example of important protein features is cellular defense.
And that’s precisely what the Nrf2 pathway does: it turns on genes that protect the cell from inflammation. So how does that actually work? Think of Nrf2 as the commander and proteins as the SWAT team.
Once in the nucleus Nrf2 turns on over hundreds of genes involved in cellular defense by activating something called the antioxident response element.4 Nrf2 also activates cytoprotective genes encoding antioxidant enzymes and detoxifying enzymes.5
If none of that makes sense to you, simply remember this: Normally, Nrf2 is turned on every 129 minutes, but when stimulated by sulforaphane it is activated every 80 minutes.6 This means you are supercharging your Nrf2 pathway when you consume sulforaphane.
Adding glucoraphanin to your diet and combining it with myrosinase gives your cells access to all the super powers of sulforaphane. How do you sprout broccoli yourself? And how much sulforaphane should you consume? We’ll talk all about that in part 3 of the sulforaphane series.
Health Dangers of Cruciferous Vegetables
In our look at the Health Dangers of a Plant-based Diet we turn to the cruciferous vegetables. You might be surprised to learn that broccoli and brussel sprouts have a dark side. I mean these are the vegetables that kill cancer, right? How can there possibly be health dangers of cruciferous vegetables?
Well just other plants, these vegetables place a high priority on survival. And this means protecting themselves with phytochemicals. The cruciferous vegetables use a special chemical called glucosinolate to deter pests. [r, r] Here we’ll look at glucosinolates and their role in the health dangers of cruciferous vegetables.
Health Dangers of Cruciferous Vegetables – What are they?
Last week as I was walking to perimeter of the grocery store (headed to the butcher) I realized how many vegetables are from the cruciferous family. It’s not just broccoli and brussel sprouts. But it also includes cabbage and cauliflower, kale and collards, radishes and arugula, mustard greens and mustard seeds, and the list goes on.
The crucifers are just every single plant specie commonly eaten today; it’s vastly different from its pre-agriculture predecessor. We transformed these plants through artificial selection to get the biggest, most pest-resistant breeds possible.
Cabbage, broccoli, cauliflower, brussels sprouts and kale are all different cultivars of a single species, Brassica oleracea. But generation by generation, we engineered this one plant’s leaves, stems and flowers into new “foods.”
You may be familiar with these crucifers because of their pungent smell. It’s the sulfur. And it’s a part of their defense.
Health Dangers of Cruciferous Vegetables – “Broccoli Bomb”
The crucifers broccoli have this chemical called glucosinolate. I to think of this chemical as the main ingredient of the “bomb.” They also have another chemical called myrosinase. I think of this as the “matchstick” that lights the bomb.
While growing out in a field the bomb and the matchstick sit in separate compartments so that the broccoli doesn’t blow itself up.
But when a little hungry animal comes looking for a snack and bites into the broccoli the bomb gets lit by the match. The explosion that results are bioactive chemicals call isothiocyanates. [r, r] One of the most well-studied isothiocyanate is call sulforaphane.
Sulforaphane is a pungent molecule (perhaps you’ve cooked broccoli and smelled it…) that can deter and kill insects, bacteria, and fungi. It causes cellular apoptosis (cell death). This happens in the cells of these small predators as well as human cells.
If you eat broccoli about 75% of the sulforaphane will be absorbed into the bloodstream and taken up by cells.
Once inside sulforaphane can damage important intracellular structures mitochondria and enzymes.
The damage increases reactive oxygen species (ROS). And in an attempt to limit the damage, glutathione, our powerful endogenous antioxidant, binds with sulforaphane to get rid of it as quickly as possible (~2-3 hours after eating it). [r] This depletes our glutathione (our most potent human antioxidant) leaving cells vulnerable to further oxidative damage.
Sulforaphane can even disrupt epithelial barriers providing yet another plant chemical that can contribute to “leaky gut.” [r, r]
Sulforaphane and Cancer
It’s not surprising that this cell killer has been recognized as an anticancer chemical. It kills cells. Cancer cells and healthy cells. [r, r, r]
Isothiocyanates sulforaphane trigger the activation of Phase II enzymes. [r] This is turning up the dial on the human immune system.
For some reason, research paints this in a positive light. Sulforaphane is a hero. Isothiocyanates increase our natural antioxidants. They say it’s a hormetic response. [r] If it doesn’t kill you, it makes you stronger.
I see it through another lense though
When the body encounters something that is damaging, it wants to get rid of it. To do this it will upregulate an army to fight it. Some of these troops are antioxidants our friend glutathione. While this is good in the context of fighting a cancerous cell or ridding the body of sulforaphane, I don’t think sending the troops to battle on a constant basis should be seen as a good thing.
The fact that the body puts such a vast importance on getting rid of sulforaphane as quickly as possible suggest to me that it’s more of a danger than a cancer-killing sidekick.
For me, a helpful analogy is to relate to chemotherapy treatment. It is very effective at killing cells. And while the intent is to kill cancerous cells, there is often a significant amount of “friendly fire” and the death of healthy cells as well.
Most people don’t take low dose chemotherapy as a cancer prevention strategy. There’s a reason for this.
Health Dangers of Cruciferous Vegetables – Thyroid Health
The isothiocyanates created by chewing up broccoli can have potent antithyroid effects and interfere with thyroid hormone production. They compete with iodine and thereby block its uptake by the thyroid. With inadequate iodine there is decreased production of thyroxine and potential for hypothyroidism. [r]
The abnormal absorption of iodine also provokes hypertrophy of the thyroid and goiter. [r]
And it’s not just humans, but animals too.
Oil meals, rapeseed meal for example, are important protein supplements for livestock. And they are high in glucosinolates. Animals can tolerate up to 5-10% rapeseed meal in their diets before suffering from goiters, depressed growth, gastrointestinal irritation, anemia, perosis, poor egg production, and liver and kidney lesions. [r, r]
The high sulfur diet can result in trace mineral deficiencies and polioencephalomalacia, a neurologic disease in ruminants.
Health Dangers of Cruciferous Vegetables – What to do
If you decide to eat cruciferous vegetables, it’s a good idea to take some protective measures.
- Adding extra iodine to counteract the thiocyanates is helpful. However, additional iodine consumption cannot counteract other glucosinolate byproducts oxazolidine-2-thiones which also blocks iodine preventing thyroxine production. [r]
- Avoid sprouts and seeds as they can have orders of magnitude more glucosinolate than matured plants. Plants protect their babies. Eat them with caution.
- Freezing as well as boiling them can help reduce the glucosinolate concentration (~50%).
Heat actually destroys the myrosinase (the matchstick that lights the bomb); however, the bacteria in our gut can act as the lighter, so sulforaphane will still be produced. [r]
As with other plant chemicals, the poison is in the dose, and an individual’s ability (or lack thereof) to disarm the plant poisons.
An elimination diet ( “Level 3” in the “30 Day Guide to Going Full Carnivore“) is a very effective way to determine your ability to handle certain plant foods, which (if any…) are ok, and in what quantity.
[NOTE: You can now access the complete “Health Dangers of a Plant-Based Diet” series here]: