Cabbage is highly recommended for breast cancer
Cabbage contains numerous substances with suspected or demonstrated cancer fighting properties, including indole-3-carbinol (I3C), 3,3'-diindolylmethane (DIM), sulforaphane, lupeol, sinigrin and several other glucosinolates. Cabbage is also a good dietary source of the lignan enterolactone. Boy choy, or Chinese cabbage, is a good source of apigenin. Cabbage has been shown to suppress inflammation, act as an antioxidant and improve diabetes in experimental mice. In addition, cabbage has been shown to inhibit urinary bladder and liver carcinogenesis, and reduce the risk of occurrence of prostate, lung, gallbladder, stomach, cervical, kidney and colorectal cancer. This anticarcinogenic activity has been found in green cabbage, bok choy (Chinese cabbage), red cabbage and to some extent in sauerkraut. As a result of its pigmentation, red cabbage contains numerous anthocyanins, some of which have anticarcinogenic activity, however green cabbage may be more chemopreventive overall than red cabbage.
Breast cancer-related effects of eating cabbage
Cabbage has been found to be promote apoptosis, suppress cell cycle progression and inhibit angiogenesis of human breast cancer cells. Furthermore, cabbage can protect against cell DNA damage. Consumption of cabbage has been shown to reduce the estrogen metabolite 16alpha-hydroxyestrone, which is a breast cancer promoter. Cabbage components I3C and sulforaphane have both been shown increase the anti-cancer effects of the chemotherapy drug Taxol (paclitaxel). One carefully designed study of Chinese women found that brassica vegetable consumption (with Chinese cabbage as a large component of the diet) was associated with significantly reduced breast cancer risk.
Additional comments
Cabbage loses a significant proportion of its chemopreventive properties when cooked. Ideally, it should be consumed raw and chopped, steam cooked, cooked for a short period of time in a small amount of water, or consumed as sauerkraut (however, select low-sodium sauerkraut).
Kimchi, a traditional Korean food typically consisting primarily of fermented Chinese cabbage or bok choy, should be consumed only in moderation by breast cancer patients, survivors and those at high risk for breast cancer. Sauerkraut has a high salt content, which should be taken into account by people who need to restrict their sodium intake. Cabbage can reduce the bioavailability of iodine in the diet.
We recommend consuming cabbage and other cruciferous vegetables as food and against consuming "broccoli pills" that have been enhanced to boost the proportion of the presumed key anti-cancer chemicals in these vegetables. There is some evidence that concentrated cruciferous vegetable extracts can act as estrogen agonists and promote breast cancer cell proliferation. Also, the anticancer properties of cabbage are likely to be the result of synergistic interaction of its various chemical components - isolated components have successfully inhibited proliferation in the laboratory, but their efficacy and safety in humans needs to be evaluated in large scale clinical trials.