There are a number of varieties of dry beans (Phaseolus vulgaris) consumed in the United States. Their chemopreventative potential varies greatly. For the purposes of this website, dry beans are defined as black beans, kidney beans, navy beans, pinto beans, pink beans, red beans and white beans.
The following beans are specifically excluded from the dry bean category: adzuki beans, black-eyed peas, chickpeas, fava beans, lentils, lima beans, and mung beans.
Dry beans are a dietary source of choline, coumestrol, cyanidin-3-glucoside (black beans), copper, and folate. Dry beans are also a good source of the lignan enterolactone. White beans are a good source of iron.

Breast cancer-related effects of eating dry beans

Postmenopausal women with breast cancer and a high intake of enterolactone have been found to be less likely to die from their breast cancer than those with a low intake. Enterolactone has also been found to increase the sensitivity of breast cancer cells to radiation, thereby potentially enhancing the treatment effects of radiotherapy.
One study found six flavonoids in the coats of black beans with potent antiproliferative activities against hormone receptor positive (ER+/PR+) breast cancer cells. Another study found that tanins isolated from black beans inhibited angiogenesis. Several studies have found that dry bean consumption reduces mammary tumor incidence and number in rats. One study that examined the cellular processes by which tumor burden was reduced reported that the dominant process was induction of apoptosis (programmed cell death). Circuling insulin and insulin-like growth factor-1 (both risk factors for breast cancer) were also reduced.
A study of the diets of 90,630 women in the Nurses Health Study II found a significant inverse relationship between breast cancer and the intake of beans. Another study found that higher intake of dry beans improved survival among postmenopausal women with breast cancer. The authors attributed this survival advantage to the lignan content of beans. Yet another study reported that women with high dry bean intake were significantly less likely to develop breast cancer, especially hormone receptor negative (ER-/PR-) breast cancer.

Additional comments

A number of studies have shown that dry beans are antiproliferative and proapoptic versus colon cancer cells and that this effect appears to be due to both soluble and insoluble components of the beans.

Sources of information provided in this webpage

The information above, which is updated continually as new research becomes available, has been developed based solely on the results of academic studies. Clicking on any of the underlined terms will take you to its tag or webpage, which contain more extensive information.
Below are links to 20 recent studies concerning this food and its components. For a more complete list, including less recent studies, please click on dry beans.