Sulforaphane: Health Benefits of Broccoli Sprouts And How They Help Fight Cancer

Sulforaphane is an organic compound containing sulfur, found in cruciferous vegetables such as broccoli, cabbage, Brussels sprouts, and kale. It has many benefits associated with it. It can boost the immune system and help prevent cancer.

This phytochemical has been studied extensively for its potential to prevent and treat cancer, especially breast and prostate cancers. And now you can add another health benefit: better brain function! It is reported that sulforaphane increases the efficiency of mitochondria. This makes it an effective way to fight age-related cognitive decline and neurodegenerative diseases like Alzheimer’s disease or Parkinson’s disease.

While the benefits of sulforaphane have been recognized for years, there is still much more to learn. Do you want to know how it can help fight cancer and other health issues? Read on!

alfalfa and broccoli sprouts on white spoons

What is sulforaphane?

Sulforaphane is a secondary plant substance from the isothiocyanate family (also called mustard oils or mustard oil glycosides), which is only found in certain plants. Cruciferous plants such as asparagus, bok choy, broccoli, cauliflower, and kale are high in this phytochemical. This is because cruciferous plants contain the enzyme myrosinase on the one hand and the glucosinolate glucoraphanin on the other. Myrosinase is an enzyme that converts glucoraphanin to the active form of sulforaphane. Chopping or chewing can do this conversion, or certain bacteria can produce it in the gut. Sulforaphane has preventive and therapeutic benefits for diseases such as cancer or diabetes. More on this in a moment.


How does sulforaphane work?

First, let’s talk about how sulforaphane works its magic. On the one hand, this phytochemical has an antimicrobial effect. This means that it can effectively fight viruses, fungi, and bacteria. On the other hand, it has an antioxidant effect. As a very strong antioxidant, it activates the body’s own enzymes that support the detoxification of the liver. It neutralizes carcinogenic free radicals and removes them from the body before they can do much damage. Because sulforaphane works indirectly, i.e. it is not used up even in this process, it remains in the body for a long time and can be highly effective for up to 5 days after consumption.


Antioxidant effect of sulforaphane

Sulforaphane has been the focus of scientific attention in recent years. Mainly to research the antioxidant effect of this phytochemical. Compared to other antioxidants, this is something very special, as the plant substance does not destroy free radicals directly, but indirectly. But how does this work? By activating detoxification enzymes in our liver (also called phase II enzymes), which filter-free radicals out of our body.

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Health benefits of sulforaphane

There are many potential benefits to sulforaphane. It can neutralize free radicals in your body, reduce inflammation, and protect you from mutations that may lead to cancer. It has been shown to slow tumor growth and, in some cases prevent the spread of tumors.


Sulforaphane and cancer

Cancer is a deadly disease that affects many people every year. While scientists have been searching for a cure for cancer for many years, they have yet to find a definitive solution. However, there may be hope on the horizon as sulforaphane.


Research on sulforaphane and cancer

Sulforaphane is often said to have anti-cancer effects on tumor stem cells. It has been shown to reduce the size and number of cancer cells in both test-tube and animal studies. In addition, it may also prevent cancer cell growth by releasing antioxidant and detoxification enzymes that protect against carcinogens. Population studies show that a higher intake of cruciferous vegetables (like broccoli) correlates with a reduced risk of cancer.

Many studies have now proven the effectiveness of sulforaphane for various tumors. Results show that sulforaphane is effective against leukemia and skin cancer. In 2006, studies at Rutgers University showed that sulforaphane can activate the body’s own protective mechanisms and thus stop the onset of cancer, even in those at genetic risk of colon cancer. Further studies have shown that sulforaphane can also be effective against breast cancer, prostate cancer, and stomach cancer.

While we need further research to confirm these findings, sulforaphane shows promise as an anticancer agent. It should be noted that concentrated forms of sulforaphane (such as broccoli sprouts or dried broccoli) are more effective than raw broccoli at preventing cancer. Sulforaphane appears to be most effective when combined with other compounds, such as vitamins and minerals.


Sulforaphane as cancer interventions

Sulforaphane is not only used for cancer prophylaxis but also in chemotherapy and cancer therapy. Some even call it the most powerful weapon in the fight against tumors. Especially because this phytochemical has also shown amazing results in advanced cancer (in tumor stem cells, among other things). How can this be? Sulforaphane intervenes in the division process of cells and destroys the microtubules (these are protein complexes inside cells) of cancer cells. If the microtubules are destroyed, the cancer cell cannot multiply any further and dies. 


Phytochemicals in vegetables fight cancer

But research shows that not only sulforaphane has the potential to slow down tumor stem cells and metastasis. Many other phytochemicals are also being intensively researched for their effect on tumors. For example, the protective effects against cancer have also been identified in the flavonoid quercetin, which is also found in broccoli, but also in many other fruits and vegetables. This shows that a balanced diet with plenty of fruit and vegetables, which is not only focused on individual plant substances, is of great importance for our health.

quinoa salad

Sulforaphane's role in heart health

Heart disease and cardiovascular disease can have many causes but are often the consequence of atherosclerosis, diabetes, obesity, and hypertension. It is the number one cause of death in the developed western world and will most likely keep its pole position for the foreseeable future. But good news: research shows that sulforaphane has several positive effects on heart health.


Oxidative stress

In the section about cancer, we already spoke about free radicals. It is completely normal to have free radicals in our bodies, but that’s why we also need a healthy amount of antioxidants. If we have too many free radicals and not enough antioxidants to neutralize them, then our body is under oxidative stress.

Free radicals are molecules that contain oxygen and are characterized by an uneven amount of electrons, which means they can easily and quickly react with other molecules, causing chain reactions that are often harmful. Oxidative stress can lead to problems such as diabetes, high blood pressure, or atherosclerosis, and therefore is often the root cause of heart disease.


Can sulforaphane lower oxidative stress?

A team at the Warwick Medical School has found that sulforaphane can activate the nrf2 protein in the body. This protein activates powerful detoxifying and anti-oxidative enzymes, which protect tissue and cells from the stress caused by oxidation. A test in humans showed that an increased intake of sulforaphane also increased the amount of active nrf2 proteins. This led to the conclusion that a sufficient intake of sulforaphane can lower oxidative stress on our body.


Benefits of sulforaphane for heart health

If oxidative stress is bad for our heart and antioxidants relieve oxidative stress, then the phytochemical sulforaphane must be good for our heart health, right? Yes, you thought exactly right. Sulforaphane is an indirect antioxidant that can activate the nrf2 protein, which produces antioxidants that can eliminate free radicals.

Animal and human studies have shown that a high intake of sulforaphane had a substantial effect on a variety of cardiovascular diseases. Especially for atherosclerosis, hypertension, and diabetes.


Actions of sulforaphane on diabetes

Diabetes is another very common disease in the developed world. It is defined as a chronic disease that impairs our ability to produce or react to insulin. People with diabetes either don’t produce enough insulin or their bodies cannot use insulin as nature designed it to. The consequence is a high blood sugar level, which over a long period can lead to a variety of serious problems, such as kidney disease, heart disease, and even blindness.


Research on sulforaphane and type-2 diabetes

Researchers have been able to show an interesting effect of sulforaphane on patients with type-2 diabetes. The aim was to see if they could find substances that would have the same effect on regulating blood sugar levels as metformin. Metformin is a common diabetes drug which helps regulate blood sugar levels but can have a variety of negative side effects. After considering over 2800 different substances, the phytochemical sulforaphane seemed to be the most promising contender.


Sulforaphane in animals

The team first started by testing the plant compound sulforaphane in cells and then moved on to animal studies. Mice and rats with type-2 diabetes showed a blood sugar level drop of 23% when taking sulforaphane. The control group that was given metformin had a reduction in blood sugar levels of 24%.

At the same time, the researchers looks at 50 genes from the liver, which were identified to play a role in type-2 diabetes. All 50 genes changed in a positive direction for the group of mice who received sulforaphane. 


Sulforaphane in humans

Sulforaphane was already proven to not cause any harm to humans. So, after the results of the animal studies, the research team started a trial on humans. They split a group of 100 patients who regularly took metformin to manage their blood sugar levels into a test and a control group. The test group kept taking metformin but were also given a dose of sulforaphane every morning for 3 months. The control group kept taking metformin as well and received a placebo.

After 3 months, the results of the test group were highly interesting. Patients with terrible glucose control and a high BMI (over 30) had a significant reduction in blood sugar levels compared with the control group. Patients who had a better glucose control, to begin with, and a lower BMI, showed a smaller improvement. This means sulforaphane showed the highest effect in patients who struggle most with type-2 diabetes, so exactly in those who need it the most.


Low blood sugar level due to sulforaphane

Sulforaphane seems to have a significant impact on our blood sugar levels as it reduces fasting blood glucose levels by over 6%. It has been shown to improve the blood sugar level of type-2 diabetes patients to the same extent and even more than the common drug metformin. And that without any of the bad side effects, many diabetes patients live the rest of their lives with.

The greatest effects were seen in participants at high risk of obesity and participants with poor glycaemic control. Accordingly, sulforaphane should be regularly integrated into the diet, especially for people with diabetes or at increased risk of diabetes.

alfalfa sprouts with jar and seed packages

Effects of sulforaphane in autism and Alzheimer's patients

Over 45 million people in the world are diagnosed with Alzheimer’s disease, an irreversible neurodegenerative disease that slowly progresses into dementia. Small memory problems are usually the first symptom, but severe dementia manifests in impaired ability to learn new things, retrieve memories, communicate, reason, and carry out standard everyday tasks. Effective therapy for Alzheimer’s is yet to be discovered.


Amyloid plaque

In the past decade, Alzheimer’s disease has been studied extensively and one of the main culprits seems to be the protein amyloid-beta (Aß). This protein exists in various different molecular forms and collects between neurons. A brain of an Alzheimer’s patient is characterized by a very high level of Aß, which sticks together and forms plaques (also known as amyloid plaques). These plaques collect between neurons and disrupt regular cell functions. High levels of Aß have also been associated with oxidative stress, another driver of Alzheimers. This research suggests that reducing Aß levels in the brain could be a strategy to prevent, maybe even therapize, Alzheimer’s disease.


Sulforaphane and Aß levels

Studies have shown that sulforaphane can cross through the blood-brain barrier and has a protective effect on neurons. So far, this has been proven in a variety of in vitro cell culture trials and in vivo animal trials. As discussed before, reducing Aß levels in the brain would reduce amyloid plaque and oxidative stress on the brain. Both things seem to be good strategies to prevent Alzheimer’s disease.

Sulforaphane has proven to have anti-oxidative effects and has been shown to protect our brain from Aß-induced oxidative stress. More research has made a strong link between sulforaphane and its protective effect to reduce Aß plaques, neurobehavioral deficits, and oxidative stress. This suggests that sulforaphane is an important phytochemical for preventing and even curing Alzheimer’s disease.


Sulforaphane and osteoarthritis

Osteoarthritis is the most common form of arthritis. Obesity and aging are the main reasons for this disease. Over time, the cartilage in our joints breaks down and the bone beneath changes, leading to pain in our hips, knees, and hands. According to the Global Burden of Disease Study from 2019, over 500 million people worldwide are being affected by osteoarthritis. That is 7% of the global population. Interestingly, women seem to be more affected by this condition than men.


Plant compound sulforaphane as a therapy for osteoarthritis

Laboratory studies have shown that sulforaphane reduces the breakdown of cartilage in our joints. Mice who were on a sulforaphane-rich diet showed a significant reduction in cartilage damage and, therefore, osteoarthritis compared to a mice control group who did not receive sulforaphane.

But not just studies in mice have shown a connection between sulforaphane and a decreased risk of osteoarthritis. Studies with human tissue supported these findings. Sulforaphane seems to work in two ways. First, it can block the formation of enzymes, which are responsible for the degradation of cartilage. And secondly, because of its anti-inflammatory effect, it reduces and prevents the painful inflammatory processes associated with osteoarthritis.

Can sulforaphane prevent osteoarthritis?

Sulforaphane is not only researched for treating people who are already affected by osteoarthritis, but also as a preventative phytochemical. The best treatment is always prevention but giving healthy people drugs just to prevent future diseases is not a good idea. This is where diet and lifestyle come in.

High dietary consumption of sulforaphane seems to have a prophylactic effect. It is, therefore, worthwhile to include more broccoli and broccoli sprouts in the diet to minimize the risk of developing arthritis later on. 


Impact of sulforaphane on our immune system

Our immune system protects our bodies from diseases, germs, and changes in cells that could lead to illness. It plays a vital role in keeping us alive every day. As long as your immune system is intact and running smoothly, you don’t even notice everything it is doing for you. Only when your immune system is weakened do you notice how valuable its function are and how important it is to support it.


Sulforaphane supports immune functions

As we have already seen, sulforaphane has antioxidant and anti-inflammatory effects. These properties make the secondary plant compound an important component of a healthy immune system and help us fight diseases. But Sulforaphane has also shown to be able to switch on a variety of antioxidant enzymes and genes in immune cells, which helps to fight free radicals that damage cells and result in diseases.

Sulforaphane reacts with the Nrf2 protein, a major player in the antioxidant response of our bodies. It can switch on a variety of antioxidants and rejuvenating genes to help our body fight diseases.


Broccoli as potential prevention for Covid-19

The Covid-19 pandemic has been challenging for everyone. Recent research has investigated how sulforaphane can prevent and treat Covid-19 infections.

Sulforaphane reduces inflammation in the body. An inflammatory response to Covid-19 is a major driver for this disease to worsen, maybe even leading to death. Controlling excess inflammation with a string antiviral response is the key to dealing with this disease. This reduced the virus load, minimizes damage to the lungs, and lets us recover from this flu quickly.

Sulforaphane reduces pro-inflammatory cytokines, which leads to anti-inflammatory effects that can help treat diseases caused by bacteria and viruses. Research in Covid-19 patients has shown that sulforaphane can help reduce the production of cytokines, which leads to less inflammation in the body.


Sulforaphane in broccoli

sandwich with broccoli sprouts

How much sulforaphane does broccoli contain?

Broccoli, in particular has a very high sulforaphane content, but not all broccoli is the same. Studies have shown that broccoli sprouts contain 10 to 100 times more sulforaphane than adult broccoli. One tablespoon of broccoli sprouts contains as much sulforaphane as 500 g of broccoli. So it also depends on how and in what form broccoli is consumed as food. Sprouted foods often have a much higher nutrient density. 


What are broccoli sprouts?

Broccoli sprouts are the first seedlings to emerge from broccoli seeds. They are practically the very first stage in the development of full-grown broccoli. Everyone is familiar with broccoli, as it is one of the most commonly consumed vegetables in Europe. Broccoli sprouts, on the other hand, have only recently gained popularity. Mainly because of the many health benefits, tender green-white sprouts are becoming more and more popular.

Broccoli sprouts are easy to grow yourself at home and within a few days. They are a great addition to salads, soups, vegetable side dishes, or dips, as well as green smoothies.


How to Grow Broccoli Sprouts

Broccoli sprouts are often readily available in the supermarket. But they can be expensive and they are much lower in nutrients due to the time it takes until they end up on your plate. The best option is to grow your own broccoli sprouts at home.

Broccoli seeds can easily be sprouted (or germinated) at home. All you need is water, a jar and a sprouting lid to rinse and drain the seeds during germination. One tablespoon of the seeds will produce about three cups of sprouts, so you really don’t need many seeds.

For a complete guide on how to grow sprouts at home, take a look here.


Sulforaphane supplement: Is it a good idea?

You absolutely don’t like broccoli or other cruciferous vegetables, but would still like to eat optimally? Unfortunately, sulforaphane is not found in many foods. But I have two other options for you:


Sulforaphane supplements

Sulforaphane capsules or broccoli capsules are a good alternative for those who cannot or do not want to take in enough sulforaphane through food. These capsules are a natural, purely herbal food supplement with a high dose of sulforaphane. This makes this food supplement a good preventative measure for many diseases. 

However, it is important to pay close attention to the ingredients. The capsules should contain pure broccoli seed extract (mustard oils) and not other potentially harmful ingredients. I would also recommend buying only organic capsules, as they are consumed raw and should not be contaminated with pesticides or other harmful substances. 


Broccoli sprouts

Another option is broccoli sprouts. These taste much milder than their adult brother and are hardly comparable in taste. They taste mild, with a slightly spicy flavor that is more reminiscent of cress than broccoli. Broccoli sprouts are also a good alternative because their sulforaphane content is many times higher than adult cruciferous vegetables. 

Broccoli sprouts should only be eaten raw, as sulforaphane is not heat resistant. If you cook or blanch your sprouts, the sulforaphane content will be drastically reduced. Since broccoli sprouts should be consumed raw, it is also important to look for high organic quality when choosing the seeds. Just as with other foods you consume raw, you certainly don’t want to ingest pesticides with your food.

Broccoli sprouts taste best mixed into salads, as a soup topping, on avocado toast, or simply in a green smoothie.


Does sulforaphane have side effects?

Though sulforaphane is safe when consumed in plant form, there is not enough quality research to know if it is safe for long-term use or higher doses of the supplement. Sulforaphane supplements have little to no side effects in doses under 200 mg/day, but pregnant and breastfeeding women are advised not to take them. There has been little research done on the potential side effects of the supplement, particularly if taken over a long period or in high doses.


Sulforaphane is an important component of the diet

The research is unanimous: sulforaphane has a thoroughly positive effect on our body, our immune system, and our metabolism. A sufficient intake of food high in this phytochemical can save us from many health problems later on. But not only that. Existing diseases such as osteoarthritis and even some cancers can be partially treated.

Sprouty Jar Starter Set Package

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The Sprouty Starter Set includes everything you need to get started: two jars with stainless steel mesh lids for continuous sprouting, high-quality ceramic trays, and two packages of seeds so that you can get started right away!

Hannah Reeves

Hello, I am the founder of Hey Sprouty and I am passionate about sustainability and living a simpler, healthier and happier life. I love to cook and to grow my own veggies. I also can't live without the sunshine! That's why I moved to Portugal. When I don't work on Hey Sprouty to share my passion for sprouts, then I am working to transform a neglected piece of land into a permaculture food forest.

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