Cruciferous veggie benefits

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Optimize Your Cells' Detoxification / Cleansing Ability

For about 20 years, we've known that many phytonutrients work as antioxidants to disarm free radicals before they can damage DNA, cell membranes and fat-containing molecules such as cholesterol. Now, new research is revealing that phytonutrients in crucifers, such as cabbage, work at a much deeper level. These compounds actually signal our genes to increase production of enzymes involved in detoxification, the cleansing process through which our bodies eliminate harmful compounds.

The phytonutrients in cruciferous vegetables initiate an intricate dance inside our cells in which gene response elements direct and balance the steps among dozens of detoxification enzyme partners, each performing its own protective role in perfect balance with the other dancers. The natural synergy that results optimizes our cells' ability to disarm and clear free radicals and toxins, including potential carcinogens, which may be why cruciferous vegetables appear to lower our risk of cancer more effectively than any other vegetables or fruits.

Recent studies show that those eating the most cruciferous vegetables have a much lower risk of prostate, colorectal and lung cancer-even whencompared to those who regularly eat other vegetables:

In a study of over 1,000 men conducted at the Fred Hutchinson Cancer Research Center in Seattle, WA, those eating 28 servings of vegetables a week had a 35% lower risk of prostate cancer, but those consuming just 3 or more servings of cruciferous vegetables each week had a 44% lower prostate cancer risk.

In the Netherlands Cohort Study on Diet and Cancer, in which data was collected on over 100,000 people for more than 6 years, those eating the most vegetables benefited with a 25% lower risk of colorectal cancers, but those eating the most cruciferous vegetables did almost twice as well with a 49% drop in their colorectal cancer risk.

A study of Chinese women in Singapore, a city in which air pollution levels are often high putting stress on the detoxification capacity of residents' lungs, found that in non-smokers, eating cruciferous vegetables lowered risk of lung cancer by 30%. In smokers, regular cruciferous vegetable consumption reduced lung cancer risk an amazing 69%!

Human population as well as animal studies consistently show that diets high in cruciferous vegetables, such as cabbage, are associated with lower incidence of a variety of 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.

Reviewing 94 studies that evaluated the relationship between Brassica vegetables and cancer, researchers found that in 67% of the case control studies, eating these vegetables was associated with a reduced risk of cancer. In 70% of the studies, cabbage consumption was associated with a lower risk of cancer, especially of the lung, stomach and colon.

In addition to its cancer-preventive phytonutrients, cabbage is an excellent source of vitamin C, an antioxidant that helps protect cells from harmful free radicals.

How many weekly servings of cruciferous vegetables do you need to lower your risk of cancer? Just 3 to 5 servings-less than one serving a day! (1 serving = 1 cup)

To get the most benefit from your cruciferous vegetables, be sure to choose organically grown vegetables (their phytonutrient levels are higher than conventionally grown), and steam lightly (this method of cooking has been shown to not only retain the most phytonutrients but to maximize their availability).

For a brief overview of the process through which cruciferous vegetables boost our ability to detoxify or cleanse harmful compounds and examples of how specific phytonutrients in crucifers work together to protect us against cancer, see our FAQ: Optimizing Your Cells' Detoxification/Cleansing Ability by Eating Cruciferous Vegetables.

Promote Gastrointestinal Health

Recent research has greatly advanced scientists' understanding of just how Brassica family vegetables such as cabbage, cauliflower, broccoli, kale and Brussels sprouts may help prevent colon 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, which include sulforaphane and indole-3-carbinol, and 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 may also offer special protection to those with colon cancer-susceptible genes, suggests a study conducted at Rutgers University and published online 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 enzymes called kinases that are expressed not only in animals, but also in humans, with 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."

Promote Women's Health

Much research has focused on the beneficial phytonutrients in cabbage, particularly its indole-3-carbinole (I3C), sulforaphane, and indoles. These two compounds help activate and stabilize the body's antioxidant and detoxification mechanisms that dismantle and eliminate cancer-producing substances. I3C has been shown to improve estrogen detoxification and to reduce the incidence of breast cancer. In one small human study, researchers found that after I3C was given for 7 days, the rate at which estrogen was broken down through the liver's detoxification pathway increased nearly 50%. In addition, recent research is showing that it's not only how much estrogen a woman has that puts her at risk for breast cancer, but how her estrogen is metabolized. The route of estrogen metabolism via 2OH (2-hydroxylation), 4OH or 16OH pathways determines how active and possibly mutagenic a woman's estrogen actually is. I3C has been shown to promote the formation of the most benign estrogen metabolite, the 2OH form.

A case control study published in the journal Cancer Research confirmed that women who eat more Brassica family vegetables have a much lower risk of breast cancer. In this study of over 300 women in Shanghai, China (where Brassica vegetables such as Chinese cabbage are frequently consumed), the women's urinary levels of isothiocyanates (a type of beneficial compound found in Brassica vegetables) directly correlated with their breast cancer risk. Those women with the highest isothicyanate levels (i.e., those women consuming the most Brassica vegetables) had a 45% lower risk for breast cancer compared to those with the lowest levels of isothiocyanates.

This significant protective effect is not all that surprising considering that the isothiocyanates provided by Brassica vegetables, such as cabbage, are capable of numerous breast cancer-inhibiting actions including:

    * inducing the production of Phase II enzymes in the liver, which bind to potential carcinogens and remove them from the body
    * inducing apoptosis, the self-destruct sequence the body uses to eliminate old or cancerous cells
    * beneficially affecting the way in which steroid hormones, including estrogen, are metabolized and the way in which the estrogen receptors on cells respond to the hormone
    * and preventing excessive cellular proliferation

Sulforaphane, potentially by altering gene expression, increases the production of antioxidants and detoxification enzymes, both of which help eliminate carcinogenic compounds, thus preventing tumors. In laboratory animals, sulforaphane has reduced breast tumor occurrence by more than 40%. One of the ways in which sulforaphane works its protective magic is by stimulating the production of glutathione, one of the body's most important internally produced antioxidants which plays a significant role in several liver detoxification pathways. An in vitro study published in the Journal of Nutrition suggests that sulforaphane can even help stop the proliferation of breast cancer cells in the later stages of their growth.

Cabbage's role as a staple vegetable in Polish cuisine may be why the breast cancer risk of Polish women triples after they immigrate to the U.S., rising to match that of U.S.-born women, suggests research presented at the American Association for Cancer Research's 2005 annual cancer prevention meeting in Baltimore, MD.

The study included hundreds of Polish women and Polish-born women in the U.S. who are part of the Polish Women's Health Study, a case-control breast cancer study. Participants were given a food frequency questionnaire that assessed their cabbage consumption when they were 12 to 13 years old and as adults.

Compared with women who ate only one serving or less of cabbage per week during adolescence, those who ate four or more servings were 72% less likely to develop breast cancer as adults.

In Poland, women typically eat an average of 30 pounds of cabbage and sauerkraut per year, while American women consume just 10 pounds per year. Polish women also traditionally eat more raw cabbage and sauerkraut in salads or as a side dish.

Although the lowest rate of breast cancer was found among women who consumed high amounts of raw- or short-cooked cabbage during adolescence, high consumption during adulthood also provided significant protection even among women who had eaten little cabbage during adolescence.

Proper cabbage preparation and cooking methods are essential for receiving its cancer-preventive effects:

Cabbage provides anti-carcinogenic glucosinolates, which are formed by the activity of myrosinase enzymes released when cabbage is sliced or chopped. Cooking denatures the myrosinase enzyme, thus stopping the production of glucosinolates.

In the body, the breakdown products of glucosinolates are thought to affect both the initiation phase of carcinogenesis-by decreasing the amount of DNA damage and cell mutation-and the promotion phase, by blocking the processes that inhibit programmed cell death and stimulate unregulated cell growth.

Cabbage foods were categorized as raw (raw sauerkraut and fresh cabbage), short-cooked (steamed sauerkraut and cabbage), and long-cooked (hunter's stew, cabbage rolls, and pierogi). Cabbage's protective effect was seen only for raw and short-cooked cabbage, not long-cooked, which was eliminated from the analysis.

To promote the production of the most glucosinolates, slice or chop your cabbage and let sit for 5-10 minutes before cooking, and cook lightly, steaming or sautéing for 5 minutes or less.

Peptic Ulcer Treatment

Raw cabbage juice is well documented as being remarkably effective in treating peptic ulcers. In one study, 1 liter of the fresh juice per day, taken in divided doses, resulted in total ulcer healing in an average of 10 days. The high content of glutamine, an amino acid that is the preferred fuel for the cells that line the stomach and small intestine, is likely the reason for cabbage juice's efficacy in healing ulcers.

Red Cabbage Protective against Alzheimer's Disease

In Alzheimer's disease, an increase in the production or accumulation of a protein called beta-amyloid protein results in brain cell damage and death from oxidative (free radical) stress. Antioxidant polyphenols abundant in red cabbage, particularly its anthocyanins, can protect brain cells against the damage caused by amyloid-beta protein, suggests a study published in Food Science and Technology.

Red cabbages contain significantly more protective phytonutrients than white cabbages:

The vitamin C equivalent, a measure of antioxidant capacity, of red cabbages is six to eight times higher than that of white cabbage.

A 100 gram (about 3 ounces) serving of raw red cabbage delivers 196.5 milligrams of polyphenols, of which 28.3 milligrams are anthocyanins. White cabbages yield 45 milligrams of polyphenols including .01 milligram of anthocyanins per 100 grams. Summing up their study results, the researchers concluded: "additional consumption of vegetables such as red cabbage may be beneficial to increase chemopreventive effects in neurodegenerative diseases such as Alzheimer's."

Cardiovascular Benefits

Consumption of cruciferous vegetables, such as cabbage, is known to reduce the risk of a number of cancers, especially lung, colon, breast, ovarian and bladder cancer. Now, research reveals that crucifers provide significant cardiovascular benefits as well.

Researchers from the University of Hawaii have shown that, at the tiny concentration of just 100 micromoles per liter, a phytonutrient found in cruciferous vegetables, indole-3-carbinol, lowers liver cells' secretion of the cholesterol transporter, apolipoproteinB-100 by 56%! Apolipoprotein B-100 (apoB) is the main carrier of LDL cholesterol to tissues, and high levels have been linked to plaque formation in the blood vessels.

When liver cells were treated with I-3-C, not only was apoB-100 secretion cut by more than half, but significant decreases also occurred in the synthesis of lipids (fats), including triglycerides and cholesterol esters. (Maiyoh GK, Kuh JE, et al., J Nutr.)