Physiological effects of broccoli consumption

Abstract

Epidemiological studies suggest that broccoli can decrease risk for cancer. Broccoli contains many bioactives, including vitamins C and E, quercetin and kaempferol glycosides and, like other members of the Brassicaceae, several glucosinolates, including glucobrassicin (3-indolylmethyl glucosinolate) and glucoraphanin (4-methylsulphinylbutyl glucosinolate). A key bioactive component responsible for much of this activity may be sulforaphane (1-isothiocyanato-4- methylsulfinylbutane), a hydrolysis product of glucoraphanin. Sulforaphane not only upregulates a number of phase II detoxification enzymes involved in clearance of chemical carcinogens and reactive oxygen species, but has anti-tumorigenic properties, causing cell cycle arrest and apoptosis of cancer cells. The bioequivalency of sulforaphane and whole broccoli have not been fully evaluated, leaving it unclear whether whole broccoli provides a similar effect to purified sulforaphane, or whether the presence of other components in broccoli, such as indole-3-carbinol from glucobrassicin, is an added health benefit. Dietary indole-3-carbinol is known to alter estrogen metabolism, to cause cell cycle arrest and apoptosis of cancer cells and, in animals, to decrease risk for breast cancer. Recent research suggests that both dietary broccoli and the individual components sulforaphane and indole-3-carbinol may offer protection from a far broader array of diseases than cancer, including cardiovascular and neurodegenerative diseases. A common link between these oxidative degenerative diseases and cancer may be aggravation by inflammation. A small body of literature is forming suggesting that both indole-3-carbinol and sulforaphane may protect against inflammation, inhibiting cytokine production. It remains to be seen whether cancer, cardiovascular disease, dementia and other diseases of aging can all benefit from a diet rich in broccoli and other crucifers. © 2008 Springer Science+Business Media B.V.