Broccoli Sprouts: One of Nature’s Top Cancer-Fighting Foods
Sometimes, powerful world-changers come in small packages. Believe it or not, this is very true for broccoli sprouts, the precursor to mature broccoli.
Until the last couple of decades, vegetable sprouts were given little to no attention from a nutritional standpoint. However, a 1997 piece in the New York Times changed all that, making the general public aware of the incredible cancer-fighting compounds found in broccoli sprouts.
Because they aren’t as readily available as regular broccoli, you might be tempted to pass on broccoli sprouts. However, I’m confident that once you know the amazing things scientists have discovered these sprouts can accomplish, you’ll rethink that position. (Maybe I’ll even convince you to start growing them at home!)
What Are Broccoli Sprouts?
Many people assume that broccoli sprouts are essentially the same as mature broccoli from a nutritional standpoint. However, that couldn’t be further from the truth — broccoli sprouts may not have the high quantity of vitamins like K and C found in adult broccoli, but they contain a great deal more glucosinolates.
Why does it matter if broccoli sprouts contain high amounts of glucosinolates? For that, let’s get into a little food science.
Brassica vegetables, including broccoli sprouts as well as other cruciferous veggies (kale, arugula, radishes and more) contain an enzyme called myrosinase that functions as part of gut bacteria to break down glucosinolates into their “usable” forms, one category of which is known as isothiocyanates.
Isothiocyanates seem to activate other enzymes responsible for transforming and/or removing xenobiotics (disease-causing compounds) from the body. Some sources describe this process as a “host defense mechanism” that is activated by relatively small amounts of isothiocyanates and causes your body to employ its natural disease-fighting power. (1)
Broccoli sprouts contain extremely high levels of glucoraphanin, the glucosinolate precursor to the isothiocyanate sulforaphane. Actually, these sprouts pack between 10–100 times the amount of glucoraphanin than adult broccoli. (2) The exact quantity of glucoraphanin depends on the date picked (three days seems to be the ultimate sweet spot) and how the sprouts are prepared (raw is best — cooking eliminates a lot of the myrosinase). To most effectively take advantage of these compounds, thoroughly chew your sprouts. (3)
Still with me? Let’s simplify it for the remainder of this article. Like most researchers, I’ll simply refer to this incredible compound as sulforaphane (as opposed to glucosinolate-derived sulforaphane or myrosinase-accompanied glucoraphanin).
Now that we’ve established how this works, let’s talk a little bit about why we should care about sulforaphane.
For one, this compound has some super impressive cancer-preventing and cancer-fighting capabilities that I’ll discuss in detail in just a moment, but that’s not the only thing it can do. Sulforaphane has been shown to support the heart, bones and respiratory system, and it might help your body fight off a common infection, detoxify environmental chemicals, combat autoimmune disease and even protect your brain after serious injury.
One way sulforaphane seems to accomplish these things is through epigenetics, an exciting new scientific discovery about how genetic changes can be accomplished by changes to diet and lifestyle. Epigenetics is the science of the “layer” on top of our DNA that instructs cells to turn off and on, how to function, and so on. Sulforaphane has been found to influence the epigenetic layer of certain parts of DNA that influence a number of disease-fighting functions.
Sound too good to be true? Just wait until you hear the science behind it all.
Benefits of Broccoli Sprouts
- May Fight and Prevent Cancer – including throat, lung, colon, prostate, breast, bladder, skin cancers
- Might Benefit the Heart
- Support Strong Bones
- Might Help Fight H. pylori Infection
- Detoxify the Body
- May Improve Respiratory Function
- Can Be Part of a Multiple Sclerosis Diet
- Could Protect Your Brain
1. May Fight and Prevent Cancer
Remember that 1997 article in the New York Times? The title of that piece is “Researchers Find a Concentrated Anticancer Substance in Broccoli Sprouts.” More than any other phenomenon, the ability of broccoli sprouts to fight cancer is its most extensively researched and well-known feature.
How does it work? (This is a pretty technical description, so feel free to skip down a few paragraphs if you’re not into the gritty details.)
First of all, sulforaphane inhibits the function of phase I enzymes, which activate pro-carcinogens (substances that are metabolized into carcinogens) in the body. (4) Then, it induces phase II enzymes to begin their work — unlike phase I enzymes, phase II enzymes detoxify your body of potential carcinogens and other disease-causing compounds (the scientific term for this is “xenobiotic metabolism”). (5)
Eating broccoli sprouts can also influence the amount of a fascinating protein known as Nrf2. It’s interesting because this protein functions early in life as an antioxidant likely to serve in cancer prevention but, once cancer has spread, also seems to promote tumor growth. Researchers observe the activity of HDAC, a cancer-promoting protein, to determine how Nrf2 is functioning in the body — the more activity in Nrf2 pathways, the less HDAC is expressed. They also look at the expression of the p16 gene, a cancer suppressor that inhibits HDAC.
In animal studies, sulforaphane was able to exhibit strong cancer-fighting ability in mice with high Nrf2 concentrations but had very little effect in Nrf2-deficient mice. Reducing HDAC in human colon cancer cells causes sulforaphane to double its ability to cause p16 expression and potentially stop that cancer from growing further. A human study found that those eating more than five servings of cruciferous vegetable servings a week or taking a broccoli sprout supplement had higher p16 expression and lower HDAC, according to colonoscopy screenings. (6)
Lastly, many of the benefits of sulforaphane (not limited just to cancer-preventing) are connected to epigenetics, as I mentioned. Sulforaphane might be able to influence some of the epigenetic changes in specific types of cancer cells and possibly reverse negative alterations in genetic code that worsen or induce some cancers. (7)
As complicated as that might sound, those are the bare basics of broccoli sprouts and cancer prevention. Here are the various types of cancer studied for their relationship to broccoli sprouts and sulforaphane:
Throat Cancer: Researchers from the University of Pittsburgh and Johns Hopkins University presented a review in 2015 detailing the way broccoli sprout extract protects against oral cancer (specifically, head and neck squamous cell carcinoma) in mice and how it is very tolerable in human volunteers. These two facts combined warrant further study in high-risk human subjects about this form of cancer. (8, 9)
Lung Cancer: A mouse study in 2005 tested the ability of sulforaphane to prevent lung cancer caused by tobacco carcinogens. The results were promising and led the scientists to suggest these substances should be tested to help prevent lung cancer “in smokers and ex-smokers with early lung lesions.” (10)
Colon Cancer: The examples in my explanation of how sulforaphane can help prevent cancer included mice with colon cancer as well as colon cancer cells. Other studies have found the same results. A lab study found that sulforaphane from broccoli sprouts and other cruciferous vegetables causes cell death and permanent DNA breakage in colon cancer cells while leaving healthy cells unaffected. (11)
Prostate Cancer: Both animal and human studies have reflected an impact of broccoli and broccoli sprouts on prostate cancer. The selenium found in both broccoli and its sprouts stops the expression of a protein called NGK2D ligand, which negatively affects the immune system and causes it to overact and then shut down in cancers, including leukemia, prostate cancer and melanoma. (12, 13)
Regular consumption of broccoli sprouts also seems to halt the development of prostate cancer tumors in mice. (16) A very small human study saw some improvements but not to a very significant threshold, as expected. Even so, those doing the study said they want to repeat the study with higher doses of sulforaphane and a larger number of subjects, particularly since the side effects were essentially null. (17)
Breast Cancer: A mouse study discovered that sulforaphane stops the growth of breast cancer stem cells and suggests it’s a useful dietary method to protect from breast cancer. (18) In humans, another small trial found some positive changes but non-statistically significant changes in tumor biomarkers usually used to test improvement of cancer development. (19)
Bladder Cancer: Another study in mice tested the effectiveness of a broccoli sprout extract on bladder cancer. Researchers found the bladder to benefit quite a bit — because the extract is delivered directly to the part of the bladder (the epithelium) where bladder cancer develops, it was a very promising result in preventing bladder cancer and slowing or stopping its spread. (20)
2. Might Benefit the Heart
A 2012 study found that rats given sulforaphane from broccoli sprouts showed lower blood pressure after the sulforaphane stopped an epigenetic process called DNA methylation that researchers believe to be correlated with hypertension. (22)
It’s even possible broccoli sprouts can be beneficial for a serious heart injury known as myocardial reperfusion injury. This injury occurs as a result of a common medical practice administered after a heart attack known as percutaneous coronary intervention (PPCI). PPCI is used to widen arteries immediately after heart attack and prevent further damage but often results in oxidative stress and cell death within the heart and connected arteries. (25)
Rats were fed broccoli sprouts for 10 days and then subjected to heart attack and two hours of reperfusion. The rats fed broccoli sprouts experienced less cell death and oxidative stress during the process, suggesting that preemptively adding broccoli sprouts to the diet might help aid in recovery for those at risk for heart attack. (26)
3. Support Strong Bones
Early reports indicate sulforaphane might be a powerful protector against osteoporosis. In a lab, sulforaphane from broccoli sprouts seems to stop molecular processes and inflammation related to the formation of osteoblasts, which are a major cause of osteoporosis. (27)
Epigenetics play a role here, too. A study in mice found that sulforaphane influences the epigenetic layer to counteract mechanisms that contribute to the formation of osteoporosis. (28)
4. Might Help Fight H. pylori Infection
Some studies have found that the H. pylori infection didn’t go away after giving broccoli sprout extract. However, broccoli sprouts seem to protect the gastric lining (mucosa) from oxidative stress associated with the development of gastritis and eventually gastric cancer. (32, 33) They may also reduce the future colonization of H. pylori.
Eating broccoli sprouts has a distinct anti-inflammatory effect when it comes to H. pylori, too, which means they could significantly help your body fight illness and disease related to infection by this bacteria. (34, 35)
5. Detoxify the Body
Many fad “detoxes” aren’t worth the dollars they cost because nature has already provided powerful detoxing foods that you can use to make your own detox drinks to get rid of many of the environmental and dietary pollutants your body needs to trash — just more proof that food is medicine.
One such example is a broccoli sprout drink. Two human studies in congested areas famed for their toxin overload in the air found that the broccoli sprouts in their drinks resulted in excretion of far larger quantities of airborne chemicals than people drinking a placebo. (36) One of the studies specifically tested for carcinogen biomarkers, finding the participants were significantly detoxing these dangerous chemicals after just 10 days. (37)
6. May Improve Respiratory Function
That same detox power might be one reason sulforaphane is good for respiratory health. Lab and human studies have discovered that broccoli sprouts and sulforaphane aid cells in the lungs get rid of environmental toxins (namely, diesel exhaust) that are known to contribute to allergies, asthma and other respiratory illness. (38, 39)
Do you remember that sulforaphane induces phase II enzymes in cancer? Those enzymes are also expressed in the upper airway when exposed to ingested sulforaphane and may decrease inflammation from oxidative stress connected with asthma. (40)
Researchers also conducted a study in mice that found sulforaphane decreased oxidative stress and limited replication of the RSV virus, the most common cause of lower respiratory illness in infants and young children. (41)
7. Can Be Part of a Multiple Sclerosis Diet
In a mouse model, sulforaphane decreased inflammation and oxidative stress (are you seeing a pattern yet?) associated with the demyelinating seen in MS. (43) “Demyelinating” is the process by which the body’s immune system damages the myelin sheath surrounding nerve fibers and is the cause of the severe symptoms associated with MS.
8. Could Protect Your Brain
Some “nutraceuticals” (medicinal foods) protect your brain from long-term, slowly developing problems that arise late in life. Others, like broccoli sprouts, might help to relieve some problems associated with trauma.
For one, immediately administering sulforaphane after traumatic brain injury (TBI) has been found to help reduce brain swelling. (44) It also enhances cognition in patients who get it within an hour after TBI. (45)
These are obviously times in which physicians and emergency personnel will be giving treatment to patients — don’t try feeding broccoli sprouts to your loved ones if they have head injuries; get them to a hospital!
However, other brain issues might benefit from the dietary use of broccoli sprouts. One example is in stroke — it seems possible that regularly eating broccoli sprouts prior to stroke might help reduce disruption of the blood-brain barrier and neural dysfunction after strokes have occurred. (46)
Finally, there have been multiple rat studies in which blood flow to the brain was restricted and then sulforaphane was given to the animals. In these tests, blood flow blockage was minimized, and the brain was somewhat protected from oxygen deprivation. The latter result is significant because that deprivation has been known to cause cerebral palsy. (47, 48)
Broccoli Sprouts Nutrition
Broccoli sprouts nutrition is a little tricky, because many commercially available broccoli sprouts are sold in supplement form. Since they have to be bought so quickly after sprouting, it’s rare to actually purchase fresh broccoli sprouts at the grocery store. (So, I’ll give you some information on how to grow broccoli sprouts in a moment.)
A four-ounce serving of freshly harvested broccoli sprouts (about 84 grams) probably contains about: (49)
- 35 calories
- 5 grams carbohydrates
- 2 grams protein
- 0.5 gram fat
- 4 grams fiber
- 54 milligrams vitamin C (60 percent DV)
- 90 micrograms vitamin A (10 percent DV)
- 78 milligrams calcium (6 percent DV)
- 720 micrograms iron (4 percent DV)
And, don’t forget, one of the most important features of broccoli sprouts is the fact they contain 10–100 times the sulforaphane found in mature broccoli.
How to Grow Broccoli Sprouts
If you’re interested in how to grow broccoli sprouts yourself, look no further. Broccoli sprouts take a little longer to sprout than many other seeds, but it’s worth the health benefits. (Plus, if you live in a warm climate, you’re likely to see a faster result.)
- Conventional sprout growing requires a jar with sprouting lid, some broccoli seeds and purified water. In your jar, cover about 2 tablespoons of organic broccoli sprouting seeds with warm water (a few inches of water will do), and soak overnight. Drain your seeds after 8–10 hours.
- For about 5 days, be careful to rinse the seeds with fresh, purified water between two and three times each day. You’ll need to drain off the water each time you rinse the sprouts (or they could go bad).
- During this growing time, be sure to keep your sprouts in a warm, dark environment.
- In the first three days or so, you’ll likely see the seeds split and reveal the beginnings of a sprout. However, don’t harvest them yet.
- When you notice the sprouts are an inch to an inch and a half long and have developed defined, yellow leaves, it’s safe to expose your sprouts to some sunlight. Continue to water and rinse as before, especially if you live in a very hot or dry place.
- Sprouts are ready to be picked and eaten when the leaves are a darker shade of green and longer than an inch in length.
Not sure how you feel about this process? There are a variety of more automated ways to grow broccoli sprouts, like a tray seed sprouter (for multiple types of seeds) or self-watering sprout systems. However, even the most traditional method only takes a few minutes each day.
Broccoli Sprouts vs. Plain Broccoli vs. Broccoli Seed Oil
Since broccoli sprouts are so nutritious, should you give up eating regular broccoli? What about broccoli seed oil, the essential oil pressed from broccoli seeds?
Actually, all three of these broccoli products are amazing in their own right. Take full advantage of the benefits of broccoli by using them each in turn.
All of them help prevent certain cancers (broccoli seed oil is known to help prevent UV damage related to skin cancer) and support age-related ailments (skin degradation, bone health, etc.).
Broccoli seed oil is known for its topical benefits for skin and hair and is a great substitute for silicone and retinol beauty products. It also helps moisturize the skin.
Broccoli and broccoli sprouts both support detoxification, heart health, bone health and brain health.
Mature broccoli contains much higher amounts of vitamin K, vitamin C, vitamin A, folate, vitamin B6, manganese, potassium, phosphorus and magnesium than broccoli sprouts, which is one of the reasons it’s such a staple vegetable in most places around the world. Broccoli is also associated with other benefits, such as liver protection, teeth/gum health, wound healing, eye health, blood pH balancing, fertility, hormonal health and weight management.
However, broccoli sprouts and their associated sulforaphane levels are known for being part of a diet for MS, fighting H. pylori infection, improvement of respiratory function, and a potential way to help protect the brain before and after serious injury.
Where to Find and How to Use Broccoli Sprouts
As I mentioned, broccoli sprouts aren’t nearly as easy to come by as broccoli. My preferred method of getting broccoli sprouts is simply growing them on my own.
You may live near a health food or grocery store that offers broccoli sprouts for sale. Keep in mind that you want to get them just a few days after sprouting and that they will probably be a bit pricey.
The third option is to take a broccoli sprout supplement. While it may sound like an easy way to get plenty of sulforaphane, broccoli sprout supplements are a little tricky. Multiple studies about broccoli sprout supplements have found that the sulforaphane is less bioavailable (absorbable) in supplements than fresh sprouts because there is no myrosinase activity in processed supplements. Myrosinase is the enzyme your digestive system uses to break sulforaphane down into the form it can be used by the body. (50)
Without myrosinase activity, sulforaphane is three to four times less bioavailable in supplements, which is why I recommend growing these sprouts yourself if you can. (51)
The No. 1 way to get the best nutrient load from broccoli sprouts is by thoroughly chewing raw broccoli sprouts, according to research. (52, 53) Unfortunately, boiling broccoli sprouts renders some of their nutrients void. (54)
Broccoli Sprouts Recipes
Just because they’re raw doesn’t mean broccoli sprouts have to be boring!
For example, try this tangled carrot and broccoli sprout salad with tahini dressing. Not only will you have a tasty way to eat broccoli sprouts, but you’ll get the benefits of apple cider vinegar and lentils.
The possibilities are vast. If you’re not interested in using them in a salad, try adding them to a burger or sandwich, along with noodles or even in your morning smoothie — among other broccoli sprouts recipes.
History and Facts About Broccoli Sprouts
Until the 1970s or so, broccoli sprouts were generally ignored, as were most other healthy sprouts. However, research in the early 1990s confirmed the belief many health-conscious folks had in the ’70s — broccoli sprouts were an extremely nutritious and altogether different food than mature broccoli.
According to Wikipedia, the New York Times article that sparked so much interest in these sprouts in 1997 actually created a global shortage of broccoli because that sort of demand was unprecedented. (55)
Since then, the interesting facts about these sprouts come from the science sector, as researchers continue to find new and novel ways these sprouts can help advance nutritional science.
Precautions and Side Effects
There are rarely side effects associated with eating broccoli sprouts. (56) Occasionally, study participants have reported mild gastrointestinal discomfort while eating them regularly.
WebMD reports that sulforaphane-containing foods like broccoli sprouts may have moderate interaction with medicines broken down by the liver, such as some muscle relaxers and/or pain meds. (57) Check with your doctor if you aren’t sure how your medications might interact with broccoli sprouts.
Because they are raw and just recently broken from seeds, sprouts such as these carry a slightly higher risk of foodborne illness. In the last 20 years, at least 30 cases of foodborne illness via fresh sprouts have been reported. Many organizations recommend cooking sprouts thoroughly or avoiding them if you are pregnant or immunocompromised. (58)
- Broccoli sprouts are a surprisingly powerful little food with thoroughly researched health benefits. Most notably, they have been shown to significantly impact several types of cancers.
- This and other benefits of broccoli sprouts are often related to the sulforaphane they contain, a protein found in these sprouts between 10 and 100 times more often than mature broccoli.
- Sulforaphane from broccoli sprouts is associated with heart health, strong bones, fighting H. pylori infection, detoxification, respiratory health, support in multiple sclerosis, and even brain protection from traumatic injury or stroke.
- I prefer to grow my own broccoli sprouts, since it’s such a simple process and gives me the chance to eat them super fresh. Try them on salads, burgers, with noodles or even as part of a smoothie.
Rebekah EdwardsDr. AxeJanuary 17, 2018