While fruits and vegetables are excellent sources of nutrients, the consumption of vegetables is more helpful in reducing cancer because they contain much higher amounts of cancer-protective compounds--especially green vegetables. Among these green vegetables, the cruciferous family has demonstrated the most dramatic protection against cancer. Cruciferous vegetables (broccoli, brussels sprouts, cauliflower, kale, bok choy, collards, arugala, watercress, and cabbage) contain a symphony of phytonutrients with potent anti-cancer effects.
Isothiocyanates (ITCs), which are perhaps the best studied, have been shown to provide protection against environmental carcinogen exposure by inducing detoxification pathways, thereby neutralizing potential carcinogens. These vegetables also contain indole-3-carbinol (I3C). Indole-3-carbinol has been shown to reduce the risk of breast cancer by decreasing estrogen activity.
Important recent studies have shown that cruciferous vegetables
and the compounds they contain can do the following:
* halt the growth of breast cancer cells1
* dramatically reduce the risk of colon cancer2
* prevent the replication of prostate cancer cells and induce death of cancerous cells3
* inhibit the progression of lung cancer4
What makes these studies even more fascinating is the discovery of the gene/diet interaction, which has shown that high intake of greens and cruciferous vegetables provides the food factors necessary to interact with--and prevent--genetic defects from creating disease. This gene/diet interaction activates a battery of many genes, initiating DNA repair and other protection mechanisms.
These cellular repair and detoxification mechanisms are most powerfully induced by eating a mixture of both raw and cooked cruciferous plant foods. Some of the compounds are water soluble and heat stable, and absorption is increased when cooked, for example, in a soup. Other critical ITCs are heat sensitive and are better transmitted in the raw form.
1. Johnston N. Sulforaphane halts breast cancer cell growth. Drug Discov Today 2004;9(21): 908. Rose P, Huang Q, Ong CN, Whiteman M. Broccoli and watercress suppress matrix metalloproteinase-9 activity and invasiveness of human MDA-MB-231 breast cancer cells. Toxicol Appl Pharmacol 2005;S0041-008X.
2. Seow A, Yuan JM, Sun CL, et al. Dietary isothiocyanates, glutathione S-transferase polymorphisms and colorectal cancer risk in the Singapore Chinese Health Study. Carcinogenesis 2002;23(12): 2055-261.
3. Wu HT, Lin SH, Chen YH. Inhibition of cell proliferation and in vitro markers of angiogenesis by indole-3-carbinol, a major indole metabolite present in cruciferous vegetables. J Agric Food Chem SK, Choi S, et al. Sulphoraphane-induced cell death in human prostate cancer cells is initiated by reactive oxygen species. J Biol Chem 2005; 280(20):19911-19924. Xiao D, Srivastava SK, Lew KL, et al. Allyl isothiocyanate a constituent of cruciferous vegetables inhibits proliferation of human prostate cancer cells by causing G2/M arrest and inducing apoptosis. Carcinogenesis 2003;24(5):891-897.
4. Conaway CC, Wang CX, Pittman B, et al. Phenethyl isothiocyanate and sulforaphane and their n-acetylcysteine conjugates inhibit malignant progression of lung adenomas induced by tobacco carcinogens in A/J mice. Cancer Res 2005 65(18): 8548-8557.