Brown rice is recommended for breast cancer
While all types of rice (Oryza sativa L.) are a good source of energy, white rice (polished or milled rice) contains a limited amount of micronutrients. White rice is a dietary source of potassium, magnesium, and calcium, as well as copper, iron, molybdenum, manganese and zinc. The positive health-related benefits of consuming rice are for the most part limited to brown (i.e., unmilled, whole grain) rice, not white rice. Brown rice has been shown to have antioxidant, hypoglycemic, anti-inflammatory, antimutagenic and cardioprotective properties. Brown rice contains numerous biologically active substances, including the carotenoids beta-carotene, lutein and zeaxanthin, as well as tricin, α-tocopherol, ү-tocotrienol, ү-oryzanol, caffeic acid, ferulic acid, methoxycinnamic acid, and momilactone B. Black, purple and red rice also contain the anthocyanins cyanidin 3-glucoside, peonidin 3-glucoside, malvidin, and cyanidin hexoside, as well as several cyanidin dihexosides.
Brown rice or its components have been shown to induce apoptosis and inhibit proliferation of human lymphoma, Ehrlich ascites carcinoma, myeloma, colorectal cancer and liver cancer cells and carcinogen-induced colon cancer in laboratory rats. Fermented brown rice has been shown to inhibit carcinogen-induced development of oral, stomach, and colon cancer in rats. Consumption of brown rice has been shown to be associated with reduced risk of pancreatic cancer in a San Francisco bay area population (however, note that high rates of pancreatic cancer in southern Louisiana have been explained, in part, by consumption of locally grown rice incorporating high levels of cadmium).
Breast cancer-related effects of eating brown rice
Brown rice and its components have been shown to inhibit the growth and proliferation of human breast cancer cell lines and mouse mammary tumors.
Additional comments
Rice represents a major path of arsenic exposure for people who depend on a rice diet. Generally speaking, rice has more elevated arsenic levels than all other grains, with brown rice having higher levels than white rice. Arsenic is contributed both by arsenic in the soil and arsenic in rice field water, much of which is naturally occurring. A 2008 report found unacceptable arsenic levels in common U.K. brands of baby foods. Most of the rice in the baby foods were thought to come from Europe. Ten of the 17 samples tested used organically grown rice. High levels of arsenic have also been reported in rice from areas of the United States where former cotton fields have been converted to rice production. Arsenic herbicides were used in cotton fields in the early to mid-20th century. In addition, southern Louisiana is home to numerous oil refineries and petrochemical plants that have introduced cadmium and other carcinogenic contaminants to some of the soil used for rice production. Cadmium exposure has been associated with increased risk of breast cancer, among other cancers. Although the U.S. is a net rice exporter, it imports specialty rice varieties such as jasmine and Basmati rice from countries such as Thailand and India. This rice is often grown under conditions and using pesticides and fungicides that would be unacceptable inside U.S. borders. Rice grown in California is most likely to have low levels of arsenic and other contaminants.
Wild rice (e.g., Zizania palustris) refers to four species of plants, three of which are native to North America, that are closely related to rice. The anthocyanins in wild rice, black rice and other darkly pigmented rice are degraded least by stovetop cooking. Using a pressure cooker results in the most thermal degradation, followed by using a rice cooker.
White rice has been stripped of much of the chemopreventive compounds and fiber that make brown rice a healthy food choice. A 2011 study found a link between increased starch intake after a diagnosis of early-stage breast cancer and a greater risk of recurrence.
Rice bran oil is used as a cooking oil and salad oil in parts of Asia. It is valued for its high smoking point and delicate flavor. While rice bran oil appears to have some chemopreventive properties, not enough information is available to make a recommendation with respect to its consumption.
Chinese red yeast rice (red mold rice) is a food spice and medicinal herb made by fermenting a type of yeast (Monascus purpureus Went) with white rice. It contains a mixture of monacolins, one of which is essentially identical to lovastin, a statin used for lowering cholesterol. Chinese red yeast rice has been shown to inhibit tumor cell growth and enhance apoptosis of colon cancer cells. It also has been found to inhibit both androgen-dependent and androgen-independent prostate tumor growth in human prostate cancer xenografts in mice. However, note that when nine different commercially available Chinese red yeast rice dietary supplements were tested in one study, the total monacolin content ranged from 0% to 0.58% w/w and only one of the preparations contained all 10 possible monacolins. In addition, measurable concentrations of citrinin, a mycotoxin known to cause kidney damage, was found in seven of the nine samples.