Broccoli sprouts

Broccoli sprouts are 3 to 4 day old broccoli plants that look like alfalfa sprouts but taste like radish. The radish flavor comes from a phytochemical that acts as protection against vectors while the broccoli plant is still young. This phytochemical not only benefits the young plant, but when eaten by humans, acts as an antioxidant to stimulate the ability of animal cells to protect against disease.

History

While health-conscious people in the 1970s embraced raw sprouts as a dietary staple, it was not until the 1990s that broccoli sprouts burst into the mainstream.

That is because in 1992, a team of Johns Hopkins University scientists isolated a cancer fighting phytochemical in broccoli called glucoraphanin, which is the glucosinolate precursor of sulforaphane (thus, sulforaphane glucosinolate or SGS).[2] When chewed, broccoli releases glucoraphanin and myrosinase, an enzyme found in another part of the plant cell, which work together to produce sulforaphane, which, in turn, stimulates the body’s immune system to deactivate free radicals. The 1992 study was followed by the discovery in 1997 that SGS is in higher concentrations in the 3 to 4 day old broccoli sprouts, at least 20 times the concentration of full grown broccoli. This discovery was written about in the New York Times[3], and created a global shortage of broccoli seed that could not meet the sudden high demand.

Nutrition

A nutrient powerhouse, broccoli sprouts contain numerous vitamins, minerals and phytochemicals, all of which are the subjects of hundreds of scientific studies. The phytochemicals include carotenoids, glutathione, indoles, monoterpenes, and thiols. Broccoli sprouts also contain Vitamins A, C and E, calcium and fiber, among a long list of nutrients.

Research

Hundreds of research studies occur every year on the cancer preventive potential of plant nutrients. The cancer preventive property of cruciferous vegetables and SGS is the subject of over 700 research studies to date. The following table is a representation of the epidemiological evidence of cancer prevention by cruciferous vegetables.

Epidemiological Evidence of Cancer Prevention by Cruciferous Vegetables

Site of Cancer	Amount of Crucifers Eaten	RR - relative risk OR-odds ratio (P value)	Reference
Bladder	>5 servings/week	RR 0.49 (0.008)	Michaud et al. (1999)
Lymphoma	>5 servings/week	RR 0.67 (0.03)	Zhang et al. (2000)
Prostate	5 servings/week	OR 0.61 (0.006)	Kolonel et al. (2000)
Prostate	>3 servings/week	OR 0.50 (0.02)	Cohen et al. (2000)
Colon (men)	Top 20%	RR 0.76 (0.011)	Voorips et al. (2000)
Colon (women)	Top 20%	RR 0.51 (0.004)	Voorips et al. (2000)
Breast	Top 25%	OR 0.05 (0.01)	Fowke et al. (2003)
Kidney	Top 25%	OR 0.53 (0.001)	Yuan et al. (1998)

Source: E.H. Jeffrey, Phytochemical Review, 2008.

Sulforaphane works as a potent catalyst to boost Phase 2 enzymes in the body. These detoxification enzymes trigger ongoing antioxidant action for at least 72 hours. As a result, the indirect antioxidant activity of sulforaphane lasts significantly longer than that of direct antioxidants such as vitamins C, E and beta carotene. Furthermore, 3-day-old sprouts have a much higher concentration of SGS than the average mature broccoli (73 mg v. 11 mg per serving, respectively), which means that one ounce of broccoli sprouts contains as much SGS as over 1¼ pounds (20 ounces) of market-stage broccoli.

The body of scientific knowledge concerning SGS and broccoli sprouts continues to grow at a rapid rate; key studies with respect to SGS are summarized below. Although research suggests a promising role for SGS in promoting health, the research results do not permit definitive scientific conclusions on specific health benefits. At this time, the U.S. FDA has not reached any such conclusions or authorized any claims specifically for SGS or broccoli sprouts.

Summaries of some key studies:

CANCER:

Carcinogen Detoxification

Potential to detoxify carcinogens. An elevated level of hepatitis virus and environmental toxins results in a very high prevalence of liver cancer in a rural area of China. Scientists performed a clinical test to assess whether broccoli sprouts influenced the body’s abilities to detoxify carcinogens. In a single-blinded placebo-controlled trial, 100 test and 100 control subjects drank a water extract of 3-day-old broccoli sprouts or a placebo daily over a period of two weeks. The broccoli sprouts group showed a significant decrease in aflatoxin-DNA adduct (a biomarker of DNA damage) levels with increasing levels of broccoli sprout consumption. The change in these biomarkers signals an enhanced detoxification (neutralization) of carcinogens from the human body leading to a reduction in cancer risk.
—Cancer Epidemiology, Biomarkers Prevention, 2005; 14(11).

Tumor Progression and Activity The inhibition of lung cancer tumors. Scientists reported that sulforaphane and another isothiocyanate (PEITC) could prevent initial benign tumors in the lungs of mice produced by a cigarette carcinogen from developing into malignant cancer tumors. Using a model in which the animals were exposed to the carcinogens, scientists demonstrated that sulforaphane inhibits the progression of the disease by causing the programmed death of the damaged cells. Findings suggest that chemoprotective agents might be useful among people exposed to tobacco carcinogens, including current smokers, ex-smokers or those exposed to second-hand smoke.
—Cancer Research, 2006, 65 (18):8538-8547.

Stomach Cancer

Suppression of H. pylori infection. Infection with the bacterium H. pylori can cause stomach ulcers and markedly increases the risk of developing stomach cancer. In vitro and animal experiments showed potent and selective antibacterial properties of sulforaphane and sulforaphane’s ability to selectively target the H. pylori bacteria, which are often difficult to eradicate. Also, sulforaphane was effective against H. pylori strains that had developed resistance to the typical antibiotic treatment. In a Japanese study involving patients infected with H. pylori bacteria, patients eating 100 grams (approximately 3½ ounces) of broccoli sprouts daily for 2 months experienced substantially reduced measures of H. pylori infection when compared with control subjects fed a vegetable with no SGS. These results suggest that SGS from broccoli sprouts may be responsible for the reduction of the bacteria and that a diet rich in SGS may be useful in reduction of H. pylori infection and chemoprevention against gastric cancer.
—Proc. Natl. Acad. Sci. USA, 2002, 99(11):7610-7615.
—Cancer Epidemiology, Biomarkers & Prevention, 2005, 14(11.2): 2754s.

Skin Tumors

Skin tumor formation after exposure to UV radiation. Mice were exposed to damaging levels of UV light for 20 weeks in a study conducted at Johns Hopkins Medical School. Following the exposure, application of sulforaphane resulted in a 50 percent reduction in the number of mice with tumors. The number of tumors per mouse and the mass of tumors were also reduced. A significant aspect of the study is that administration of the chemoprotective agent was after carcinogen exposure, suggesting an ability to prevent the progression of cancer after cells are already damaged.
—Cancer Epidemiology, Biomarkers & Prevention, 2005, 14(11).
―Cancer Letters, 2006, 240:243-252.
―Cancer Research, 2006, 66:8293-8296.
―Proc. Natl. Acad. Sci., USA, 2007, 104(44):17500-5.

Breast Cancer

Work from Johns Hopkins, published in 1994, demonstrated chemoprotective effects of sulforaphane, showing its ability to reduce mammary tumor formation in rats. Scientists at Shanghai Cancer Center in China conducted a retrospective (epidemiological) study of 350 pairs of women. One of each pair had breast cancer. The other was cancer-free. The study results revealed that women who had eaten higher levels of Brassica vegetables -- broccoli, cabbage, cauliflower and kale— all of which contain SGS and related compounds -- were 50 percent less likely to be diagnosed with breast cancer. Cornblatt and colleagues (2007) have now shown that sulforaphane actually reaches breast tissue in humans within an hour or so of consumption.
—Cancer Research, 2003, 63:3980-3986.
―Carcinogenesis, 2004, 25:219-227.
―Carcinogenesis, 2007, 28(7):1485-1490.

Prostate Cancer

Prostate cancer cell inhibition. Human prostate cancer cells responded to treatment with sulforaphane in the form of broccoli sprout extracts, showing dramatic increases in their Phase 2 protective enzymes. Dr. James D. Brooks, Urology Department, Stanford University, suggests broccoli sprouts, a rich natural source of sulforaphane, might be appropriate for use in intervention trials in humans.
—Cancer Epidemiology, Biomarkers & Prevention, 2001, Vol. 10, pp. 949-954.
―Carcinogenesis, 2004, 25:83-90.
―BMC Cancer, 2006, 6:62.

Colon Cancer

Colon cancer cell inhibition. American Health Foundation researchers showed that sulforaphane significantly inhibited the formation of colon cancer in rats. Much work has demonstrated the ability of sulforaphane and broccoli sprouts extracts to inhibit cancer in human colon cancer cells.
―Proceedings of the American Association for Cancer Research, 2000; 41:660.
―J. Nutrition, 2005, 135: 1865-1872.
―Cancer Chemother. Pharm., 2006, 57:317-327.

Bladder Cancer

Prevention and control of bladder cancer. Epidemiological evidence strongly suggested a role for cruciferous vegetables in prevention of bladder cancer. Indeed, although an analysis of 47,909 men in the Health Professionals Follow-Up Study showed virtually no correlation between cancer reduction and high consumption of fruits and vegetables overall, or yellow or green leafy vegetables specifically, it did show a statistically significant reduction among those men who consumed large amounts of cruciferous vegetables.

Several studies have suggested that the bladder is one of the most responsive organs to induction of detoxification enzymes by extract, and demonstrated that this was evident in human bladder cancer cells in vitro and using broccoli sprouts rich in sulforaphane potential in animal models in vivo. In addition, studies have also shown that sulforaphane and broccoli sprout extract can induce apoptosis and cell cycle arrest in human bladder cancer cells in vitro, while showing that activity levels from pure sulforaphane and broccoli sprout extracts were virtually equivalent, confirming that this effect is due exclusively to the sulforaphane potential in the sprouts, not other components.
―Journal of the National Cancer Institute, 1999, 91(7):605-613.
―Journal of Nutrition, 2004, 134:2004-2010.
―Mol. Cancer Ther., 2006, 5(4):935-944.
―Cancer Research, 2008, 68(5):1593-1600.

Impact on Developing or Developed Cancers

Cancer cell apoptosis and cell cycle arrest. French researchers showed that sulforaphane might do more than just activate antioxidants. Their research describes the ability of sulforaphane to cause cancer cells to self-destruct, known as apoptosis or programmed cell death. The multidimensional ability of sulforaphane both to eliminate or detoxify carcinogens and to kill cells with potential cancer-causing mutations suggests that SGS may have broader effects on developed cancer at various stages as well as prevention.
—Cancer Research, 2001, 61(16): 6120-6130.
―Current Cancer Drug Targets, 2006, 6:135-145.

Antimetastatic activity. Scientists at the Amala Cancer Research Centre in India reported that sulforaphane may inhibit the spread of B16F-10 melanoma cells in vitro. Mice were treated with sulforaphane either prior to, simultaneously, or following exposure to the carcinogens. Results indicated the simultaneous treatment of sulforaphane was most effective with a 95% reduction of lung tumor formation and a 94% increase in the life span of the animals. The findings suggest that sulforaphane may have the ability to prevent metastasis of established cancers, rather than simply preventing development of cancers.
—Life Science, 2006; 78(26):3043-3050.

OTHER HEALTH CONDITIONS:

Cholesterol Levels

In a pilot study, researchers at Tokyo University of Agriculture and The Japan Institute for the Control of Aging found that individuals who ate 3-1/2 ounces of broccoli sprouts a day for just one week showed decreased overall levels of cholesterol, while increasing HDL or good cholesterol. The SGS in broccoli sprouts also appear to reduce the amount of oxidative stress or cell destruction caused by free radicals.
—Biofactors, 2004, 22:271-275.

High Blood Pressure

In laboratory studies with animals that are bred to have high blood pressure and are therefore at high risk for stroke, Dr. Bernhard Juurlink at the University of Saskatchewan in Saskatoon, Canada, found that sulforaphane-induced Phase 2 enzymes from broccoli sprouts improved cardiovascular health by decreasing inflammation and improving heart, artery and kidney function.
―Proc. Natl. Acad. Sci. USA, 2004, 101(18):7094-7099.

Macular Degeneration

Johns Hopkins University scientists studied the ability of sulforaphane to protect retinal pigment epithelial cells from damage by chemical carcinogens and by UV light. These processes are the similar to the kind of damage that can lead to macular degeneration in the eye. Macular degeneration is the leading cause of blindness among the elderly.
—Proc. Natl. Acad. Sci. USA, 2001, 98(26):15221-15226.
—Proc. Natl. Acad. Sci. USA, 2004, 101( 28): 10446-10451.
―Invest. Opthamol. Vis. Sci., 2005, 46: 979-987.

COPD

Researchers in the Department of Environmental Health Sciences and the Division of Pulmonary and Critical Care Medicine at Johns Hopkins School of Medicine report that sulforaphane increases the activity of the phase II enzyme gene Nrf2 in human lung cells which protects cells from damage caused by toxins. Thus, presenting the possibility of therapy directed toward enhancing Nrf2-regulated antioxidants reducing the effects of oxidative stress in COPD.
―Am J Resp Crit Care Med, 2008, 178(6):592-604.

Diabetes

Sulforaphane activates the Nrf2 protein, which protects cells and tissues from damage by stimulating the phase 2 enzymes, which detoxify ROS molecules. Sulforaphane reduced Reactive Oxygen Species (ROS) molecules by 73%, thus reducing damage to blood vessel cells by hyperglycemia. High glucose levels can cause a three-fold increase in ROS levels, which can damage human cells. These results suggest that sulforaphane from broccoli may help reverse the damaging effects of diabetes-linked vascular disease.
―Diabetes, 2008, 57:2809-2817.

Availability

Broccoli sprouts are available in grocery and natural foods stores across the U.S. and in other countries. Broccoli seeds are available for home growing. One can sprout broccoli seeds using a jar or a commercial sprouting kit.

Sprout safety

It is crucial that all commercial sprouting facilities adhere to written Good Manufacturing Practices (GMP), written sanitation Standard Operating Procedures (SOP), and to a certified HACCP program. Reputable sprouting facilities also submit to third party inspections by the FDA and qualified organizations (e.g. American Institute of Baking).

Seed Sanitation: The U.S. Food and Drug Administration (FDA) issued suggested protocols requiring commercially grown broccoli sprout seed to be soaked and sterilized with 20,000 PPM calcium hypochlorite prior to sprouting. The seeds are then extensively rinsed to remove all remaining residue. This sanitation step is crucial for food safety.

Hold and Release Testing: To ensure safe sprouts commercial sprout growers must test their sprouts for Salmonella and E. coli BEFORE they are sent to the marketplace. This is done by catching a sample of spent irrigation water midstream and sending the sample to an outside laboratory for analysis. Sprouts then must be held in a cold facility until the test results come back negative for contamination.

A study published in Nutrition Journal[4] quantifies the effectiveness of a sprout safety program. The recent increased interest in consuming green vegetable sprouts has been tempered by the fact that fresh sprouts can in some cases be vehicles for food-borne illnesses. They must be grown according to proper conditions of sanitation and handled as a food product rather than as an agricultural commodity. When sprouts are grown in accordance with the criteria proposed from within the sprout industry, developed by regulatory agencies, and adhered to by many sprouters, green sprouts can be produced with very low risk. Contamination may occur when these guidelines are not followed.

References

External links

• Sprouts: A Best Nutrient