Wheat bran is the hard outer layer of wheat grain. Along with wheat germ, it is an integral part of the whole grain; both are removed during milling in the production of refined flour. Wheat bran is a good dietary source of complex carbohydrates, insoluble fiber, vitamin E and B vitamins. Wheat bran also contains various phenolic acids, including ferulic acid, and has been shown to have antioxidant properties. Cereal fiber (including bran) consumption has been shown to be associated with lower risks of diabetes and cardiovascular disease. Consumption of wheat bran has also been found to be associated with lower risk of colon cancer. Note that a separate web page covers the effect of eating bread on risk of breast cancer.
Breast cancer-related effects of consuming wheat bran
The wheat bran flavonoid triticuside A has been shown to induce apoptosis and inhibit proliferation of breast cancer cells while having little cytotoxicity to normal breast cells. Consumption of wheat bran results in the production of the lignan phytoestrogen enterolactone by the intestinal microflora. This production is influenced by the nature of other foods ingested at the same time.
High levels of enterolactone in the blood have been found to be associated with decreased risk of breast cancer in most studies. 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 using a mouse model of breast cancer reported that the female offspring of mice fed a whole wheat-rich diet during pregnancy had a lower incidence of carcinogen-induced mammary tumors than controls.
Other foods derived from the wheat plant, such as wheat germ, wheat germ oil, wheat grass and wheat sprouts are thought to have a variety of beneficial health effects but few formal studies exist that examine the associations between these foods and breast cancer risk. Wheat germ oil is a good source of vitamin E. Apart from water, wheat grass juice is approximately 70% chlorophyll. Wheat grass is also a good source of protein and contains numerous enzymes, vitamins and minerals. Wheat sprouts have been shown to have relatively high anti-oxidant activity. Wheat germ extract has been shown to inhibit experimental colon carcinogenesis in rats. Avemar, a fermented wheat germ extract, has been shown to inhibit the growth of human breast cancer cells transplanted into mice.
Below are links to recent studies concerning this food. For a more complete list of studies, please click on wheat bran.