woensdag 11 maart 2009

Cancer Protection from Special Sulfur-Containing Phytonutrients

Plant phytonutrients found in Brussels sprouts enhance the activity of the body's natural defense systems to protect against disease, including cancer. Scientists have found that sulforaphane, one of the powerful glucosinolate phytonutrients found in Brussels sprouts and other cruciferous vegetables, boosts the body's detoxification enzymes, potentially by altering gene expression, thus helping to clear potentially carcinogenic substances more quickly.

Additionally, researchers in the Netherlands investigated the effect of a diet high in Brussels sprouts on DNA damage. They compared two groups of healthy male volunteers. Five men ate a diet that included 300 grams (about 10 ounces) of cooked Brussels sprouts daily, while the other five men at a diet free of cruciferous vegetables. After three weeks, the group that ate Brussels sprouts had 28% decrease in measured DNA damage. Reduced DNA damage may translate to a reduced risk of cancer since mutations in DNA allow cancer cells to develop.

Sulforaphane, which is formed when cruciferous vegetables such as Brussels sprouts 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. A study published in the Journal of Nutrition also suggests that sulforaphane may help stop the proliferation of breast cancer cells, even in the later stages of their growth.

Sulforaphane may 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 laboratory animals 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.

Brussels sprouts' glucosinolates have been shown to help prevent the development of colon cancer in response to exposure to heterocyclic amines, the carcinogenic compounds produced when meat is grilled or otherwise charbroiled. In an animal study published in Carcinogenesis, researchers looked at the effects of drinking water supplemented with Brussels sprouts or red cabbage juices on the liver and colon of laboratory animals that were also given a heterocyclic amine carcinogen.

Brussels sprouts reduced the development of pre-cancerous cells 41-52% in the colon and 27-67% in the liver, and drastically diminished the size (85-91%) of pre-cancerous lesions in the liver. Red cabbage moderately decreased (19-50%) the number of pre-cancerous lesions that developed in the liver and markedly reduced (41-83%) the size of those that did occur. These highly protective effects are due to crucifers' ability to significantly increase the activity of enzymes involved in both Phase I (CYP4501A2) and Phase II (glucuronidation via UDPGT-2) detoxification.

Brussels sprouts' stronger protective effects are thought to be due to the fact that this cruciferous vegetable contains 2-3 times the amount of glucosinolates than are found in red cabbage. Glucosinolates increase Phase II glucuronidation activity, one of the primary pathways through which toxins made even more dangerous by Phase I are rendered water-soluble and ready for elimination from the body.

New research has greatly advanced scientists' understanding of just how cruciferous vegetables such as Brussels sprouts, cabbage, cauliflower, broccoli, and kale 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.

1 opmerking:

  1. Thanks for that information. I have enjoyed your blog and will try some of your recipes.


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