Human epidemiologic studies have suggested that eating cruciferous vegetables like broccoli is associated with reduced risk of bladder cancer.
Two population-based, case-control studies have documented reduced risk of prostate cancer in men who consume cruciferous vegetables.
There is strong evidence that the protective action of cruciferous vegetables derives from isothyiocyanates, a group of phytochemicals with well-known cancer preventive activities.
Glucoraphanin, the principal glucosinolate in broccoli sprouts, can be broken down by gut microflora to sulforaphane, a potent isothyiocyanate. Sulforaphane is a potent inducer of phase 2 enzymes known to bolster the defenses of cells against prostate cancer.
In a study at Roswell Park Cancer Institute, professor Yuesheng Zhang and colleagues found that a concentrated extract of freeze dried broccoli sprouts cut development of bladder cancer in rats by more than half. The broccoli sprout’s sulforaphane was selectively delivered to the bladder tissues through urinary excretion.
Other cruciferous vegetables with isothyiocyanates include mature broccoli, cabbage, kale, collard greens and others. Broccoli sprouts have approximately 30 times more isothyiocyanates than mature broccoli. Small quantities of broccoli sprouts may protect against the risk of cancer as effectively as much larger quantities of mature vegetables.
References:
1. Bhamre S, Sahoo D, Tibshirani R, Dill DL, Brooks JD. Temporal changes in gene expression induced by sulforaphane in human prostate cancer cells. Prostate. 2008 Oct 30. PMID: 18973173.
2. Clarke JD, Dashwood RH, Ho E. Multi-targeted prevention of cancer by sulforaphane. Cancer Lett. 2008 Oct 8;269(2):291-304. PMID: 18504070.
3. .Zang y., et al. Inhibition of urinary bladder carcinogenesis by broccoli sprouts. Cancer Res. 2008 Mar 1;68(5):1593-600. PMID: 18310317.
4. Brooks JD, Paton VG, Vidanes G. Potent induction of phase 2 enzymes in human prostate cells by sulforaphane. Cancer Epidemiol Biomarkers Prev. 2001 Sep;10(9):949-54. PMID: 11535546.
5. Bhamre S, Sahoo D, Tibshirani R, Dill DL, Brooks JD. Temporal changes in gene expression induced by sulforaphane in human prostate cancer cells. Prostate. 2008 Oct 30. PMID: 18973173.
6. Jed W. Fahey, Yuesheng Zhang, Paul Talalay. Broccoli sprouts: An exceptionally rich source of inducers of enzymes that protect against chemical carcinogens. Proc Natl Acad Sci U S A. 1997 Sep 16;94(19):10367-72. PMID: 9294217.
