Turmeric is a bright yellow spice made from the dried rhizome (underground stem) of the plant Curcuma longa that is used extensively in Indian cooking. Biologically active components of turmeric include curcumin, various turmerones, and myricetin. Turmeric and its components have been shown to have antioxidant, anti-inflammatory, antibacterial, antifungal, antiparasitic, anti-thrombotic, anti-proliferative, anti-angiogenic, radioprotective, neuroprotective and cardioprotective effects.
Curcumin has been shown to inhibit proliferation and induce apoptosis of chronic and acute myeloid leukemia, Burkitt’s lymphoma, melanoma, osteosarcoma, head and neck squamous cell, esophageal, brain, thyroid, lung, synovial, pancreatic, liver, intestinal, colorectal, endometrial, cervical, bladder, ovarian, and prostate cancer cells.
Breast cancer-related effects of consuming turmeric
Curcumin has been shown in the laboratory to have profound and diverse effects on breast cancer carcinogenesis, proliferation and metastasis. Furthermore, these anticancer actions have been observed against several types of breast cancer, including estrogen receptor positive and progesterone receptor positive (ER+/PR+), ER negative and PR negative (ER-/PR-), and HER2/neu overexpressing cell lines. Some degree of selectivity for cancer cells also has been observed.
Adding curcumin to chemotherapy regimes that include Taxol (paclitaxel), Adriamycin (doxorubicin), or 5-Fluorouracil (5-FU) has been shown to enhance their cytotoxicity. Curcumin might also protect the brain from chemotherapy, thereby possibly reducing chemo brain. On the other hand, supplementation with curcumin has been shown to interfere with the effectiveness of tamoxifen treatment.
Curcumin has been shown to be an iron chelator, which may be helpful in reducing iron for some women (since high stores of iron can contribute to breast cancer risk), but could negatively impact women with marginal stores of iron, especially those undergoing chemotherapy.
Curcumin has been found in mouse models to effectively protect skin from radiation damage, while at the same time sensitizing breast cancer cells to radiation and making them more susceptible to its effects. Therefore, it appears that adding turmeric to the diet during radiation treatment does not lessen the radiation's effectiveness and could be beneficial. Also, there is some evidence that turmeric could help protect normal breast cells from radiation-induced cancer (e.g., when radiation is used to treat other cancers).
Curcumin has been shown to inhibit progestin-accelerated mammary tumors in rats. Combined hormone therapy containing both estrogen and progestin has been found to result in increased risk of breast cancer in postmenopausal women. Treatment with curcumin was found to postpone the first appearance of progestin-accelerated tumors, decrease overall tumor incidence, and reduce proliferation. These results suggest that curcumin might be an effective a dietary chemopreventive agent in women already exposed to combined hormone therapy.
Although turmeric contains up to 5% curcumin, the bioavailability of curcumin in turmeric is limited, apparently because of poor absorption and rapid elimination from the body. Therefore, the levels of curcumin used in laboratory experiments to assess its chemoprotective effects typically are many times higher than that which would result from consuming turmeric in the diet. However, we recommend consuming turmeric as food rather than taking curcumin supplements, whose safety and effective dosages for breast cancer patients and survivors have not been established.
While the in vitro and in vivo evidence of curcumin's anti-cancer activities is remarkable, there have been no population studies that specifically address the association between turmeric consumption and the risk of breast cancer (or other cancers). India, where turmeric is a dietary staple, has lower overall cancer rates and breast cancer rates than countries in the West (although the rates are rising, particularly in urban areas). One 2005 study found that south Asian women (having origins mainly in India, Pakistan, Bangladesh and Sri Lanka) living in California were 3.5 times more likely to develop breast cancer than native Asian Indian females. However, these results likely are the result of a variety of non-dietary as well as various dietary factors.
Curcumin has been shown to have a cytotoxic impact on microbes such as the malaria parasite Plasmodium falciparum. One study also showed that long-term use of low-dose curcumin supplementation suppressed immunity against some other microbes (i.e., pathogens whose elimination primarily involves reactive radicals generated from inflammation).
Below are links to recent studies concerning this food. For a more complete list, including less recent studies, please click on turmeric.