Cauliflower and other cruciferous vegetables, such as broccoli, cabbage, and kale, contain compounds that may help prevent cancer. These compounds appear to stop enzymes from activating cancer-causing agents in the body, and they increase the activity of enzymes that disable and eliminate carcinogens.
Epidemiological studies have long suggested a connection between these vegetables and resistance to cancer. However, only in the past decade have we begun to understand how these compounds work.
Sulfur-Containing Phytonutrients Promote Liver Detoxification
We now know that cruciferous vegetables contain both glucosinolates and thiocyanates (including sulforaphane and isothiocyanate). These compounds increase the liver's ability to neutralize potentially toxic substances.
If potentially toxic molecules are not properly and rapidly detoxified in the liver, they can damage cell membranes and molecules such as DNA within the cell nucleus. Such damage can start a chain reaction that may eventually lead to carcinogenesis-cell deregulation and uncontrolled growth.
Many enzymes found in cauliflower also help with the detoxifying process. These enzymes include glutathione transferase, glucuronosyl transferase, and quinone reductase.
Both animal and human studies show increased detoxification enzyme levels from high-glucosinolate diets. Researchers suggest that this helps explain the epidemiological association between a high intake of cruciferous vegetables and a decreased risk of certain cancers.
New Research Expands our Understanding of How Cruciferous Vegetables Help Prevent Cancer
New research has greatly advanced scientists' understanding of just how cruciferous vegetables such as cabbage, cauliflower, broccoli, kale and Brussels sprouts help prevent cancer. When these vegetables are cut, chewed or digested, a sulfur-containing compound called sinigrin is brought into contact with the enzyme myrosinase, resulting in the release of glucose and breakdown products, including highly reactive compounds called isothiocyanates. Isothiocyanates are not only potent inducers of the liver's Phase II enzymes, which detoxify carcinogens, but research recently conducted at the Institute for Food Research in the U.K. shows one of these compounds, allyl isothicyanate, also inhibits mitosis (cell division) and stimulates apoptosis (programmed cell death) in human tumor cells.
Sulforaphane, a compound formed when cruciferous vegetables are chopped or chewed, is already known to trigger the liver to produce enzymes that detoxify cancer-causing chemicals, inhibit chemically-induced breast cancers in animal studies, and induce colon cancer cells to commit suicide.
An in vitro study published in the Journal of Nutrition suggests that sulforaphane can also help stop the proliferation of breast cancer cells, even in the later stages of their growth.
An in vitro study published in the Journal of Nutrition suggests that sulforaphane can also help stop the proliferation of breast cancer cells, even in the later stages of their growth.
Sulforaphane may also offer special protection to those with colon cancer-susceptible genes, suggests a study conducted at Rutgers University and published online on May 4, 2006, in the journal Carcinogenesis.
In this study, researchers sought to learn whether sulforaphane could inhibit cancers arising from one's genetic makeup. Rutgers researchers Ernest Mario, Ah-Ng Tony Kong and colleagues used mice bred with a genetic mutation that switches off the tumor suppressor gene known as APC, the same gene that is inactivated in the majority of human colon cancers. Animals with this mutation spontaneously develop intestinal polyps, the precursors to colon cancer. The study found that animals who were fed sulforaphane had tumors that were smaller, grew more slowly and had higher apoptotic (cell suicide) indices. Additionally, those fed a higher dose of sulforaphane had less risk of developing polyps than those fed a lower dose.
The researchers found that sulforaphane suppressed certain kinase enzymes. These cell signaling enzymes are expressed not only in laboratory animals, but also in humans, and the ones supppressed by sulforaphane are involved in activities that promote colon cancer.
According to lead researcher, Dr. Kong, "Our study corroborates the notion that sulforaphane has chemopreventive activity…Our research has substantiated the connection between diet and cancer prevention, and it is now clear that the expression of cancer-related genes can be influenced by chemopreventive compounds in the things we eat."
In this study, researchers sought to learn whether sulforaphane could inhibit cancers arising from one's genetic makeup. Rutgers researchers Ernest Mario, Ah-Ng Tony Kong and colleagues used mice bred with a genetic mutation that switches off the tumor suppressor gene known as APC, the same gene that is inactivated in the majority of human colon cancers. Animals with this mutation spontaneously develop intestinal polyps, the precursors to colon cancer. The study found that animals who were fed sulforaphane had tumors that were smaller, grew more slowly and had higher apoptotic (cell suicide) indices. Additionally, those fed a higher dose of sulforaphane had less risk of developing polyps than those fed a lower dose.
The researchers found that sulforaphane suppressed certain kinase enzymes. These cell signaling enzymes are expressed not only in laboratory animals, but also in humans, and the ones supppressed by sulforaphane are involved in activities that promote colon cancer.
According to lead researcher, Dr. Kong, "Our study corroborates the notion that sulforaphane has chemopreventive activity…Our research has substantiated the connection between diet and cancer prevention, and it is now clear that the expression of cancer-related genes can be influenced by chemopreventive compounds in the things we eat."
Human population as well as animal studies consistently show that diets high in cruciferous vegetables, such as cauliflower, are associated with lower incidence of certain cancers, including lung, colon, breast and ovarian cancer. Now, research published in the International Journal of Cancer (Zhao H, Lin J) suggests that bladder cancer can join the list.
University of Texas researchers analyzed the diets of 697 newly diagnosed bladder cancer cases and 708 healthy controls matched by age, gender and ethnicity. Average daily intake of cruciferous vegetables was significantly lower in those with bladder cancer than in healthy controls.
Those eating the most cruciferous vegetables were found to have a 29% lower risk of bladder cancer compared to participants eating the least of this family of vegetables.
Crucifers' protective benefits were even more pronounced in three groups typically at higher risk for bladder cancer: men, smokers, and older individuals (aged at least 64).
Diagnosed in about 336,000 people every year worldwide, bladder cancer is three times more likely to affect men than women, according to the European School of Oncology.
Crucifers' well known cancer-fighting properties are thought to result from their high levels of active phytochemicals called glucosinolates, which our bodies metabolize into powerful anti-carcinogens called isothiocyanates.
Isothiocyanates offer the bladder, in particular, significant protection, most likely because the majority of compounds produced by isothiocyanate metabolism travel through the bladder en route to excretion in the urine, suggested the researchers.
University of Texas researchers analyzed the diets of 697 newly diagnosed bladder cancer cases and 708 healthy controls matched by age, gender and ethnicity. Average daily intake of cruciferous vegetables was significantly lower in those with bladder cancer than in healthy controls.
Those eating the most cruciferous vegetables were found to have a 29% lower risk of bladder cancer compared to participants eating the least of this family of vegetables.
Crucifers' protective benefits were even more pronounced in three groups typically at higher risk for bladder cancer: men, smokers, and older individuals (aged at least 64).
Diagnosed in about 336,000 people every year worldwide, bladder cancer is three times more likely to affect men than women, according to the European School of Oncology.
Crucifers' well known cancer-fighting properties are thought to result from their high levels of active phytochemicals called glucosinolates, which our bodies metabolize into powerful anti-carcinogens called isothiocyanates.
Isothiocyanates offer the bladder, in particular, significant protection, most likely because the majority of compounds produced by isothiocyanate metabolism travel through the bladder en route to excretion in the urine, suggested the researchers.
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