There are a handful of molecules that I would characterize as being close to a panacea, in that they can help almost every chronic disease. Sulforaphane is one of them. It’s an incredible molecule that’s most known for its ability to kill cancer. It will help you if you’ve got a Th1 or Th2 disorder. It’s an example of a molecule that is an immune stimulant but also an anti-inflammatory, and these are usually contradictory. Read on to discover 30+ other reasons why you should eat your broccoli (sprouts).

What are Sulforaphane and Broccoli Sprouts?

Sulforaphane (SFN) is an isothiocyanate, a sulfur-containing organic compound [1, 2].

It is derived from glucoraphanin and 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 [3].

Three-day-old sprouts of certain cruciferous vegetables contain 10 to 100 times higher concentrations of glucoraphanin than in mature plants [3].

Levels of glucoraphanin and sulforaphane are highest in broccoli sprouts [4].

Sulforaphane has antioxidant, antimicrobial, anticancer, anti-inflammatory, anti-aging, neuroprotective, and anti-diabetic properties [1].

Sulforaphane also protects against cardiovascular and neurodegenerative diseases [1].

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 [5].

Sulforaphane Benefits

Much of the information given below is derived from animal- and laboratory-based studies. Human studies are falling behind, but will hopefully soon follow.

1) Promotes Detoxification

Sulforaphane is an indirect antioxidant. It boosts the antioxidant capacity of cells by at least 2 mechanisms [6]:

  1. Inducing phase 2 detoxification enzymes – Sulforaphane is the most potent inducer of phase 2 enzymes identified to date. It acts by activating Nrf2 and ARE, and increasing glutathione S-transferase activity [4, 2, 7, 8]
  2. Increasing cellular glutathione levels

2) Prevents and Combats Cancer

Of all the molecules I’ve studied, sulforaphane and broccoli sprouts are the most promising at preventing and killing cancer.

A diet rich in Brassica vegetables decreases the risk of cancer [9, 10].

Three to five servings per week are sufficient to decrease the risk of cancer by ∼30% to 40% [9].

Subjects who consumed at least one portion of cruciferous vegetables per week had a significantly reduced risk of oral cavity, pharynx, esophageal, colorectal, breast, and kidney cancers [9].

The great thing about sulforaphane is that it kills cancer cells, but seems to have very little effect on healthy cells [11].

Sulforaphane treatment reduced DNA damage and mutation rate when cancer-causing chemicals bound to DNA [9].

Sulforaphane kills colorectal cancer cells, oral squamous cell carcinoma cells, breast cancer cells, cervical cancer cells, liver cancer cells, prostate cancer cells, and leukemia cells [12, 13, 9, 14].

SFN inhibited the growth of glioblastoma, thyroid, prostate, mammary, tongue, and lung cancer in animals [15, 16, 17, 9, 18, 19].

Broccoli sprouts significantly and dose-dependently inhibited bladder cancer development in rats, and UV-radiation-induced skin cancer development in mice [20, 21].

Sulforaphane combats cancer by multiple mechanisms:

  • SFN inhibits phase I enzymes that can activate pro-carcinogens [9]
  • SFN induces phase II enzymes that are responsible for eliminating chemicals that damage DNA [9]
  • SFN changes gene activation/deactivation, and causes demethylation, thereby restoring the activity of important tumor-suppressing and cell-cycle controlling genes [9, 9]
  • Sulforaphane induces cancer cell death [9]
  • Sulforaphane inhibits the NF-κB pathway, thus reducing inflammation [9]
  • Sulforaphane induces cell cycle arrest, and thereby inhibits cancer cell proliferation [9]

Apart from being effective in its own right, sulforaphane also enhances 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 [9].

However, although sulforaphane was found to be safe and effective in several studies, it was not effective in 2 clinical trials [22, 23].

3) Lowers Cholesterol

Eating glucoraphanin-rich broccoli significantly reduced LDL cholesterol in humans [24].

SFN is produced in the body from glucoraphanin.

In 12 healthy subjects, eating fresh broccoli sprouts (100 g/day) for 1 week decreased total and LDL cholesterol, and increased HDL cholesterol. Broccoli sprouts also improved oxidative stress markers [25].

4) Prevents and Combats Heart & Cardiovascular Disease

A diet rich in Brassica vegetables decreases the risk of cardiovascular disease [9].

Both sulforaphane and broccoli sprouts high in glucoraphanin decreased blood pressure in hypertensive rats [26, 26].

A short dietary treatment of rats with broccoli sprouts protected the heart against oxidative stress and cell death caused by ischemia (reduced blood flow and low oxygen) [27].

Sulforaphane also reduced heart damage after infarct in rats [28].

Sulforaphane protected against the hardening of the arteries (atherosclerosis), and suppressed inflammation in hardened arteries in animals [29, 30].

SFN further possesses antithrombotic activities. SFN inhibited human platelet aggregation and reduced blood clot formation [31].

SFN reduced the mortality of acute lung thromboembolism in mice [32].

Finally, sulforaphane is beneficial in stroke. In rodents, SFN decreased brain infarct (damaged tissue from a stroke) volume, and maintained the blood-brain barrier (BBB) integrity and neurological function after stroke [33, 34].

5) May Combat Obesity

In mice with Western diet-induced obesity, 3 weeks of sulforaphane supplementation reduced weight gain, leptin and insulin levels, and improved insulin resistance, glucose tolerance, and cholesterol [35].

Similarly, in another study, sulforaphane inhibited high-fat-diet-induced obesity and fat accumulation in mice. It also reduced total cholesterol, leptin, and liver triglyceride levels [30].

6) Improves Diabetes

Broccoli sprouts improve many parameters in diabetes. In type 2 diabetics, eating broccoli sprouts increased blood antioxidant capacity and HDL cholesterol, and decreased oxidative stress, triglycerides, insulin, insulin resistance, and CRP [36, 37, 38].

Sulforaphane also prevented diabetes-related complications in animals, such as [36, 39]:

  • Nephropathy
  • Tissue damage
  • Vascular complications
  • Diabetes-induced heart dysfunction
  • Thickening of the heart muscle
  • Heart damage in mice

However, in rats, while SFN had positive effects on diabetes, liver function and cholesterol were aggravated after treatment [40].

7) Can Boost the Immune System

Sulforaphane enhanced bacterial clearance by macrophages and increased the activity of natural killer cells (NK cells) in mice [41].

In studies with aging mice, sulforaphane boosted Th1 immunity and restored or delayed the decline of cellular immunity that happens with aging [42].

8) Antiviral

Broccoli sprouts enhanced human antiviral responses [41].

Broccoli sprouts reduced influenza viral load in humans [41].

SFN exhibited significant antiviral activity against influenza (the flu), HIV, Epstein-Barr virus, and the hepatitis C virus [43, 43].

SFN blocked HIV infection in macrophages. Macrophages play a critical role in HIV infection, forming long-lived viral reservoirs and distributing the virus in the body [44].

On the other hand, SFN may exacerbate infections by viruses that hijack Nrf2, such as the Marburg virus, the Kaposi’s sarcoma-associated herpesvirus (KSHV), and Dengue virus [44].

9) Combats Bacterial and Fungal Infections

In one study, 23 out of 28 tested bacterial and fungal species were inhibited by sulforaphane [45].

Mycobacterium abscessus is frequently found in patients with cystic fibrosis and in immunosuppressed patients. Pretreatment of macrophages with sulforaphane significantly decreased bacterial burden [46].

Human β-defensin-2 (HBD-2) plays an important role against bacterial invasion. Sulforaphane is able to increase antimicrobial peptides such as HBD-2 [47].

10) Protects the Skin

Sulforaphane provides protection against UVA and UVB inflammation, sunburn, and skin damage [48, 49].

UV radiation induces direct DNA damage and inflammation, and suppresses the immune response. Sulforaphane-rich extracts of 3-day-old broccoli sprouts increased phase 2 enzymes in human and mouse skin, protected against UV radiation-induced inflammation and edema in mice, and reduced susceptibility to erythema (skin redness) in humans [50].

Sulforaphane protected skin cells against oxidative stress caused by UVA radiation with a ∼50% reduction in reactive oxygen species (ROS) [9].

UVA irradiation plays a role in the premature aging of the skin by triggering oxidative stress, and inducing collagen degradation, a hallmark of photoaged skin. Pretreatment of mouse skin with sulforaphane protected against UVA-mediated collagen depletion [51].

Sulforaphane improved skin blistering in epidermolysis bullosa simplex [52].

Epidermolysis bullosa simplex (EBS) is a rare inherited condition in which the skin loses its integrity after mechanical trauma.

11) Combats Inflammation

Sulforaphane inactivated nuclear factor kappa-B (NF-κB), a key inducer of inflammation [36].

Sulforaphane also activated Nrf2, which lowered inflammation and decreased proinflammatory mediators in mice [53, 54].

12) May Combat Depression and Anxiety

Inflammation has been recognized as one of the causes of depression. By reducing inflammation, sulforaphane can help combat depression.

Repeated SFN administration reversed depression- and anxiety-like behaviors in chronically stressed mice, likely by inhibiting the hypothalamic-pituitary-adrenal (HPA) axis and inflammatory responses to stress [55, 56].

In another study, Nrf2 deficiency in mice resulted in depressive-like behavior, while the induction of Nrf2 by sulforaphane had antidepressant-like effects [57].

Also, dietary intake of glucoraphanin during the juvenile and adolescent periods in mice prevented the onset of depression-like behaviors at adulthood [56].

13) Protects the Brain and Restores Cognitive Function

Sulforaphane increased neuronal BDNF in mice, a factor that supports the survival of existing neurons and encourages the formation of new neurons and synapses [58].

SFN reduced brain inflammation in various animal models of pathogen-induced neuroinflammation and neurodegenerative disease [59, 60, 60, 61].

Sulforaphane promoted microglia differentiation from pro-inflammatory M1 to anti-inflammatory M2 state. This reduced brain inflammation and restored spatial learning and coordination in rats [62].

Sulforaphane is beneficial in various pathological conditions, as it:

  • Improved cognitive performance and reduced working memory dysfunction in rats after traumatic brain injury [63]
  • Weakened cognitive deficits in mouse models of psychiatric disease. Also, the intake of glucoraphanin during the juvenile and adolescent periods prevented the onset of cognitive deficits at adulthood [64]
  • Alleviated brain swelling in rats, by attenuating the blood-brain barrier disruption, decreasing the levels of pro-inflammatory cytokines, and inhibiting NF-κB; it also increased AQP4 (a water channel protein) levels, thereby reducing brain swelling [65, 66]
  • Prevented memory impairment and increased the survival of hippocampal neurons in diabetic rats [67]

Sulforaphane recovered memory in mice and rats with chemically induced memory impairment [68, 69, 70].

SFN exerted positive effects against brain damage induced by acute CO poisoning in rats [71].

Sulforaphane protected human neurons against prion-mediated neurotoxicity [72].

Insufficient NRF2 activation in humans has been linked to neurodegenerative diseases such as Parkinson’s disease, Alzheimer’s disease, and amyotrophic lateral sclerosis [73].

SFN, as a potent Nrf2 activator, may help in the treatment of these diseases.

14) May Help with Parkinson’s Disease

Parkinson’s disease is characterized by selective loss of dopaminergic neurons in the substantia nigra of the brain. In animal models of Parkinson’s disease, sulforaphane improved deficits in motor coordination and inhibited dopaminergic neuronal loss [74, 75, 76, 77].

15) May Help with Alzheimer’s Disease

Abnormal production and aggregation of amyloid beta (Aβ) peptide are major factors implicated in the pathogenesis of Alzheimer’s disease (AD). Broccoli sprouts protected against Aβ-induced cell death, and sulforaphane inhibited Aβ-related inflammation [78, 79, 80].

Sulforaphane reduced Aβ plaque and neuron loss, and improved cognitive impairment in Alzheimer’s disease-like mouse models [81, 82, 83].

16) May Help with Huntington’s Disease

Sulforaphane activated the protein degradation machinery that promotes huntingtin degradation and reduced huntingtin toxicity in mice [84].

17) May Prevent Seizures

Sulforaphane protected against seizures and elevated the seizure thresholds in mice [85].

18) Improves Schizophrenia

Sulforaphane improved performance in a learning task in outpatients with schizophrenia [86].

Methamphetamine can induce psychosis in susceptible people. Sulforaphane weakened behavioral abnormalities in mice after administration of methamphetamine or phencyclidine, suggesting that it may help with schizophrenia [86].

Sulforaphane protected against antipsychotic-induced toxicity in dopaminergic neurons [87].

19) May Be Beneficial for Substance Abuse

Sulforaphane weakened behavioral and neuropathological changes associated with methamphetamine exposure in mice. Pretreatment with sulforaphane weakened acute hyperlocomotion (increase in movement) in mice after a single administration of methamphetamine [88].

Also, the development of behavioral sensitization after repeated administrations of methamphetamine was significantly reduced by pretreatment with sulforaphane [88].

20) May Improve Autism Symptoms

In a clinical trial, sulforaphane improved behavior in young men with autism [89].

Sulforaphane activates genes that protect cells against oxidative stress, inflammation, and DNA-damage, all of which are associated with autism spectrum disorder [89].

21) Can Protect Against GI Injury and Inflammation

SFN protects the gut against NSAID-related damage. SFN improved aspirin/NSAID-induced injury of the gut in mice, and inhibited gastric ulcers in rats [90, 91, 92].

Nrf2-deficient mice exhibit worse colitis symptoms, indicating that SFN can help in this condition by activating Nrf2 [93].

Indeed, in another study, treatment with SFN decreased inflammation in mice with colitis [94].

22) Combats H. pylori

SFN is beneficial against Helicobacter pylori infections [93].

Broccoli sprouts inhibit the growth of H. pylori [95].

In several human studies, broccoli sprouts decreased H. pylori colonization and reduced stomach inflammation [96, 97, 98].

These effects were temporary because values went back to their original levels 2 months after treatment was discontinued [97].

In another study, broccoli sprout extract did not inhibit H. pylori colonization, but nevertheless protected the stomach lining [99].

In H. pylori-infected type 2 diabetic patients, broccoli sprout powder, in addition to standard triple therapy, considerably improved H. pylori eradication, and also improved heart health in these subjects [100].

H. pylori increases oxidative stress, thereby causing damage to the stomach lining, slowing down damage repair, and eventually inducing gastric cancer. Sulforaphane activates Nrf2-dependent antioxidant enzyme activities, thereby protecting stomach cells from oxidative injury [101].

Sulforaphane can also protect the stomach lining by reducing inflammation [97].

Improved stomach lining health also makes it more difficult for H. pylori to colonize the stomach, which explains the reduced rate of colonization found in some human studies [97].

23) Improves Liver Function

In men with fatty liver, broccoli sprouts improved liver function and decreased ALT, γ-GTP, and ALP [102].

In animals, SFN protected against a wide variety of liver diseases caused by toxic chemicals, drugs, alcohol, and high-calorie diets [102, 103, 104].

Broccoli sprouts activated detoxification and glutathione production, increasing GST while decreasing AST and ALT in rat livers [105].

Sulforaphane inhibited alcohol-induced fatty liver in mice [106].

Many drugs, including sodium valproate, cause liver toxicity. In rats, SFN significantly boosted liver function, reduced ALT, AST, and ALP, and improved valproate-induced liver damage [107].

24) Reduces Health Damage from Pollution

Sulforaphane helped the body detoxify airborne pollutants, pesticides, and heavy metals by activating detoxification systems, mainly the phase II enzymes.

In a farming community exposed to airborne pollutant with a high risk of hepatocellular carcinoma, broccoli sprouts enhanced the detoxification of airborne pollutants and reduced the risks of cancer [108].

Sulforaphane induced phase II enzymes in the upper airway of human subjects [4].

Phase II enzymes have important protective effects against diesel exhaust particles (DEP), ozone, and tobacco smoke [4].

Sulforaphane reduced the pro-inflammatory and pro-allergic effects typically caused by exposure to diesel exhaust particle [109].

Sulforaphane protected human white blood cells (lymphocytes) from pesticide-induced DNA damage [110].

Aflatoxin binds DNA and causes liver cancer. Sulforaphane reduced the binding of aflatoxin to DNA in rats [111].

Sulforaphane inhibited the mutagenicity caused by heterocyclic amines (cooked food mutagens) [112].

Cadmium reduced testosterone, sperm motility, sperm count, and increased sperm deformity in mice. SFN improved sperm quality, testosterone, and antioxidant levels [113].

Sulforaphane lessened liver damage caused by cadmium selenide in mice [114].

Exposure to arsenic increases the risk of lung disease. Sulforaphane blocked DNA damage and mild lung damage caused by 2-week exposure of mice to arsenic-containing dust [115].

25) May Be Beneficial for Airway Inflammation and Asthma

Sulforaphane has had beneficial effects in animals with asthma and airway inflammation, but studies in humans are less conclusive [116].

Broccoli sprout extract suppressed airway inflammation in humans exposed to diesel exhaust particles (equivalent to daily PM exposure levels on a Los Angeles freeway) [117].

Sulforaphane also improved airway and lung constrictions caused by methacholine in 60% of moderate asthmatics. However, in 20% of the asthmatics, sulforaphane worsened the constrictions [6].

In other human trials, broccoli sprouts did not improve asthma, COPD symptoms, or ozone-induced airway inflammation [118, 119, 120].

Patients with chronic obstructive pulmonary disease (COPD) have innate immune dysfunction in the lung, resulting in frequent bacterial infections. Sulforaphane restored bacteria recognition and phagocytosis in lung macrophages from COPD patients [121].

Sulforaphane enhanced bacterial clearance by lung macrophages and reduced inflammation in mice exposed to cigarette smoke for 6 months [121].

26) Combats Autoimmune Inflammation

Sulforaphane decreases autoimmune inflammation [122].

SFN can be beneficial against T-cell driven autoimmune disorders, such as multiple sclerosis-like diseases in animals, but studies in humans are still lagging.

Sulforaphane significantly inhibited the development and severity of MS-like disease in mice, mitigating inflammatory infiltration and demyelination in the spinal cord [122, 93].

Sulforaphane caused improvement by silencing Th17/Th1 responses within the brain/neurons [93].

NRF2-deficient mice have exacerbated pathology in this model [93].

Sulforaphane activated the Nrf2/ARE pathway, which helps combat the disease [122].

27) Sulforaphane Can Reduce Pain

Broccoli sprout extract reduced pain in mice and rats in a dose-dependent manner, possibly by activating the opioid receptors [123].

In mice, sulforaphane lessened pain, reduced pro-inflammatory cytokines, and increased anti-inflammatory cytokines. Sulforaphane blocked COX2 and iNOS in injured nerve cells, the 2 key enzymes implicated in inflammation and neuropathic pain [124].

28) Can Promote Bone Formation

In females, low levels of estrogen, such as during menopause or after an ovary removal surgery, can lead to reduced bone mass (osteoporosis).

Sulforaphane promoted bone formation and increased bone volume (∼20%) in both normal mice and mice without ovaries. Sulforaphane diminished bone resorption, thereby shifting the balance to a state favoring bone acquisition [125].

29) Can Be Beneficial for Arthritis

A sulforaphane-rich diet improved osteoarthritis in mice. Sulforaphane inhibited key metalloproteinases implicated in osteoarthritis, independently of Nrf2, and blocked inflammation through NF-κB to protect against cartilage destruction [126].

Some of the SFN effects may be mediated by Nrf2 because enhanced oxidative stress and cartilage damage were observed in Nrf2-deficient mice with arthritis [93].

SFN reduced the severity of arthritis in mice by decreasing pro-inflammatory cytokines [127].

Several inflammatory autoimmune diseases, such as rheumatoid arthritis and osteoarthritis, switch the polarization of monocytes into classically activated pro-inflammatory macrophages (M1 type).

Sulforaphane blocked the inflammatory responses specific to M1 macrophages (Th1) and shifted macrophage production to M2 macrophages [128].

M2 (Th2) decrease inflammation and encourage tissue repair.

30) Can Prevent Muscle Damage

Sulforaphane prevented muscle damage in rats after acute bouts of exhaustive exercise, by acting as an indirect antioxidant in the muscle [129].

31) May Be Beneficial for Muscular Dystrophy

Sulforaphane reduced dystrophic muscle damage and muscle inflammation in mice by inducing Nrf2 [130, 131].

In mouse models of Duchenne muscular dystrophy, sulforaphane significantly increased muscle mass, muscle force (∼30%), and running distance. Sulforaphane also reduced muscle hypertrophy, heart muscle hypertrophy, and inflammation [132].

32) Can Protect the Kidneys

SFN protected against kidney damage in animals [133, 134].

Chemotherapeutics, such as cisplatin, can be toxic to kidneys. In animals, sulforaphane prevented inflammation and kidney damage caused by cisplatin [133].

33) Can Support Hair Growth

Dihydrotestosterone (DHT) causes androgenic baldness. Sulforaphane increased the production of enzymes that degrade DHT [135].

SNF significantly enhanced hair regeneration in mice, and reduced testosterone and DHT levels in the blood [135].

SFN increased the amount of testosterone degrading enzymes, such as 3α-HSD, in the liver, accelerated the degradation of blood DHT, and reversed the suppression of hair growth by DHT [135].

34) Can Increase Alcohol Tolerance

Many East Asians are highly intolerant to even modest alcohol consumption. These people accumulate acetaldehyde, the primary metabolite of alcohol, because of a genetic polymorphism in aldehyde dehydrogenase (ALDH2) that metabolizes acetaldehyde to nontoxic acetate. Sulforaphane upregulated ALDH2 by dietary means, thereby reducing acetaldehyde toxicity [136].

In mice, SFN dramatically increased tissue ALDH2 and doubled the rate of elimination of acetaldehyde after the administration of alcohol [136].

SFN activated human salivary aldehyde dehydrogenase (hsALDH) and increased its activity towards acetaldehyde [137].

35) May Be Beneficial in Pregnancy and May Increase Offspring Health

When glucoraphanin was administered to pregnant female rats, their offspring had lower blood pressure and less tissue inflammation in adulthood, regardless of their subsequent diet [138].

Administration of broccoli sprouts during pregnancy prevented growth restriction and neurodevelopmental delays and defects in rat pups [139, 140].

36) Protects the Eyes

Oxidative stress due to excessive light exposure can exacerbate a variety of human retinal diseases by accelerating photoreceptor cell death (photoreceptors are cells that receive light and translate it into nerve impulses) [141].

SFN protected human retinal cells from UVA light-induced damage [142].

SFN also protected against photoreceptor degeneration and light-induced retinal damage in mice [143, 144].

SFN dose-dependently induced thioredoxin (TXN) in mouse retina, a factor that protects cells against oxidative stress by maintaining vitamin A and vitamin C levels [143, 144, 141].

Sulforaphane treatment significantly decreased ischemia (reduced oxygen and blood flow), a condition that induces loss of retinal function in mice [145].

SFN protected human lens cells against oxidative stress and could potentially delay the onset of cataracts [146].

Also, SFN may help prevent complications after cataract surgery [147].

Fuchs endothelial corneal dystrophy (FECD) is a condition in which a deficiency in Nrf2 is observed. SFN significantly improved oxidative stress-induced cell death in FECD human cells [148].

37) May Be Beneficial Against Keloids

Sulforaphane inhibited cell growth and reduces collagen in keloid cells [149].

38) May Improve Bladder Dysfunction

In rats with bladder outlet obstruction, SFN treatment increased bladder capacity and bladder compliance [150].

39) May Benefit Children with HGPS

Hutchinson-Gilford progeria syndrome (HGPS) is a rare childhood premature aging disorder linked to mutations in the LMNA gene. Protein clearance and autophagy are impaired in HGPS cells. SFN stimulated protein clearance by autophagy and reversed cellular phenotypic changes, both of which are the hallmarks of HGPS [151].

Sulforaphane Side Effects

1) May Transiently Decrease Genome Stability

Sulforaphane increases the activation of many beneficial genes, including tumor suppressor genes. However, sulforaphane also activates long terminal repeats (LTRs), DNA sequences found within our genome that impair genome stability and cause mutations [152].

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 [152].

Other studies on human volunteers recorded no abnormal events related to broccoli sprout consumption [153].

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 [154].

Also, after feeding raw or steamed broccoli to mice and rats, an increase in DNA adducts (cancer-causing chemicals binding to DNA) was observed [154].

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 can enhance tumorigenesis [155].

2) Excessive Consumption May or May Not Cause 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 [154].

This was also caused by consuming the mature plant and may be caused by other substances found in the broccoli plant, unrelated to sulforaphane.

Foods to Maximize Sulforaphane Bioavailability

Broccoli Sprouts Are the Richest Source of Sulforaphane

The amount of sulforaphane (glucoraphanin) can vary widely in vegetables [3].

Broccoli is not the only cruciferous vegetable which has SFN, but it yields the highest amounts, with glucoraphanin content around 75% of total glucosinolates [3].

Furthermore, 3-day-old broccoli sprouts contain 10 to 100 times higher levels of glucoraphanin than does a mature broccoli [7, 156].

Do not confuse broccoli sprouts with Brussels sprouts.

Myrosinase Is Necessary for Sulforaphane Production

The majority of SFN is formed when glucoraphanin gets processed by myrosinase, upon plant tissue damage (e.g. chopping, chewing). When plant myrosinase is inactive or absent, a small amount of SFN may still be formed by gut bacteria-derived myrosinase activity [157].

Gut bacteria, such as Bifidobacterium, Lactobacillus, and Bacteroides, have been reported to possess myrosinase-like activity [3].

Many available broccoli sprout supplements are myrosinase-inactive [3, 158].

SFN absorption was sevenfold lower for glucoraphanin supplements than equivalent glucoraphanin-containing fresh broccoli sprouts with the active enzyme [157].

SFN absorption from a glucoraphanin powder devoid of myrosinase activity improved when consumed along with an active source of myrosinase (such as air-dried broccoli sprouts) [157].

Also, combining broccoli sprouts with the broccoli powder enhanced SFN absorption from the broccoli powder [159].

Processing Inactivates Myrosinase

The bioavailability of sulforaphane from fresh broccoli is much higher than that from cooked broccoli [9].

Higher amounts of sulforaphane were found in the blood and urine when broccoli was eaten raw (bioavailability of 37%) versus cooked (3.4%) [160].

Cooking and/or blanching (during freezing process) of cruciferous vegetables inactivates myrosinase and decreases sulforaphane bioavailability [9].

Boiling for more than 1 minute, or steaming for more than 4 to 5 minutes, inactivates myrosinase [161].

Myrosinase Enhancers

Mustard seeds contain a more resilient form of myrosinase. The addition of powdered mustard seeds to heat-processed broccoli significantly increased the production of sulforaphane [162].

Avoid Nitrile Formation

Broccoli also contains significant amounts of epithiospecifier protein (ESP), an inhibitor of myrosinase. ESP produces inactive sulforaphane nitrile. Under certain conditions, as much as 75% nitrile is created. [161]

ESP is more heat sensitive than myrosinase. Steaming for 1 to 3 minutes provides less nitrile and more sulforaphane yield from a broccoli meal [163].

Sulforaphane Metabolism

Sulforaphane is rapidly absorbed, peaking in the blood as early as 1 to 3 hours after ingestion [3, 164].

Once SFN is distributed, there is evidence that it can accumulate in tissues and produce anticancer blocking and suppressing effects [165].

In the blood, sulforaphane-glutathione accounts for more than 50% of total sulforaphane metabolites [9].

SFN and its metabolites are cleared from the body within 12 to 72 hours of dosing, by urinary excretion [165, 9, 164].

Maintenance of SFN concentrations in the body can be achieved by consuming recommended servings of cruciferous vegetables once a day [165].

Additional Information

Your Genetics And Sulforaphane Metabolism

GSTs are a large family of glutathione conjugating enzymes, which attach glutathione to the substance that needs to be detoxified out of the body. Three of them, GSTM1, GSTP1, and GSTT1 have been implicated in the metabolism of isothiocyanates, and sulforaphane in particular [143].

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 [143].

Individuals with GSTM1-null mutations may benefit more from SFN due to the decreased degradation of SFN, which therefore increases exposure [143].

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 [143].

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 [143].

Broccoli sprouts are more effective in detoxification when GSTT1-positive carriers are exposed to airborne pollution compared to the null carriers [8].

SNPs in the GSTP1 gene

My Experience with Broccoli Sprouts

I started consuming broccoli sprouts about 5 years ago, but stopped about 9 months ago after I didn’t notice any significant effects.

I used to cut the top or green part off and put them on a salad.

I decided to revisit broccoli sprouts as a result of me being afraid of cancer and an improved understanding of gut health.

In particular, indoles in cruciferous veggies are very important for gut health. Indoles shift the metabolism of tryptophan to serotonin, instead of kynurenine [166].

I’ve also been afraid of getting/having a possible bacterial infection, which often produces products that block the vitamin D receptor and cause autoimmune disease. Broccoli sprouts are strong antimicrobials.

However, I realized there was a gap between my experience and the research. Whenever this happens, I step back and ask why. In this case, I figured I just wasn’t getting enough.

So then, I thought it would be too annoying to buy more broccoli sprouts and cut the tops off. I then wondered what would happen if I just put the whole container in the blender – with the bottom.

I didn’t do that before because I wasn’t sure if the bottom part was edible. Well, I still don’t know, but years of experimentation have made me somewhat fearless (perhaps a little too much for my own good).

My result? The effects are day and night from consuming the green part to putting the whole thing in a blender.

It’s extremely powerful. The effects are similar to high dose R-lipoic acid (700 mg), but it’s better. Both are HDAC inhibitors. The broccoli sprouts are also antimicrobial, which lipoic acid is not.

It’s a relaxant, an antidepressant, a potent anti-inflammatory, and an antioxidant. It felt like it would steamroll any negative gut pathogens in its way.

Overall, it’s very powerful, and I now know I’m getting the full effects when I do this. I wouldn’t want any more of an effect, anyway.

It’s critical that you put the whole container in the blender. I usually get 4 oz. containers.

On the downside, it temporarily decreases cognitive function, as do all powerful antioxidants. The brain needs some ROS to function properly. It’s honestly too strong to take daily. But, if I had cancer, I would take it daily.

When I take it at night it keeps me up, so I don’t recommend taking it at night.

Sulforaphane Mechanism of Action

Sulforaphane Is an Indirect Antioxidant:

Sulforaphane Inhibits Inflammation:

Sulforaphane Changes Gene Expression:

  • 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 [9, 11]
  • Sulforaphane inhibits DNMT1 and DNMT3A [9]
  • SFN is one of the most potent (histone deacetylase) HDAC inhibitors found to date [12]
  • SFN inhibits HDAC1, HDAC2, HDAC3, and HDAC4 [12, 9]
  • SFN decreases miR-21 and TERT [12]

Sulforaphane Induces Cell Death (Apoptosis) in Cancer:

Sulforaphane Inhibits Weight Gain:

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About the Author

Biljana Novkovic - PHD (ECOLOGICAL GENETICS) - Writer at Selfhacked

Dr. Biljana Novkovic, PhD

PhD (Ecological Genetics)

Biljana received her PhD from Hokkaido University.

Before joining SelfHacked, she was a research scientist with extensive field and laboratory experience. She spent 4 years reviewing the scientific literature on supplements, lab tests and other areas of health sciences. She is passionate about releasing the most accurate science & health information available on topics, and she's meticulous when writing and reviewing articles to make sure the science is sound. She believes that SelfHacked has the best science that is also layperson-friendly on the web.

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