Breast cancer is the most frequently diagnosed cancer in women and causes as many as 43,500 deaths among women each year in the United States, according to the University of Maryland Medical Center. Animal studies using flaxseed, the hard, tiny seeds of the flax plant, offer supporting evidence for a potential cancer-preventive effect. If you have breast cancer, speak with your doctor before using flaxseed supplements.
Lignans
Flaxseeds contain large amounts of lignans, substances with phytoestrogenic properties. Lignans might reduce the effects of estrogen in the body by binding to estrogen receptors inside cells. Decreasing the hormone's effects in this manner might help prevent those cancers that depend on estrogen, such as breast cancer, says Kiranmayi Korlagunta, a flaxseed researcher at Alagappa University in India.
Estrogen Metabolism
Flaxseed might play a crucial role in estrogen metabolism and therefore might influence circulating levels of estrogens, which in turn might decrease the progression of hormone-dependent breast cancer, notes Natalie Ledesma, a research associate at the University of California, San Francisco. In addition, lignans of flaxseed facilitate estrogen removal via urine or feces due to increased gut retention, adds Ledesma.
Aromatase
Numerous studies have documented that lignans in flaxseed potently inhibit aromatase activity, which leads to the inhibition of estrogen biosynthesis in breast cancer cells, according to the Orange Country Community College. Aromatase, a cytochrome P450 hemoprotein, plays a crucial role in estrogen production in the breast by converting androgens into estrogens, which can fuel the development of breast cancer.
Refuting Evidence
Oregon State University reports that there is little evidence that taking flaxseed supplements decreases breast cancer risk. After some promising early studies, newer results examining whether lignan-containing foods, including flaxseed, protects against colon cancer have been mixed. A meta-analysis conducted by OSU researchers found that in postmenopausal women, flaxseed was associated with a small but statistically significant reduction in breast cancer risk.
References
- Oklahoma State University; The Effects of Flaxseed on the Glucose Profile in Native American Postmenopausal Women; Kiranmayi Korlagunta; 2001
- University of California, San Francisco; Nutrition & Breast Cancer; Natalie Ledesma; Sep. 2008
- Orange County Community College, Suny Orange Online Biology Library: Breast Cancer
- Oregon State University, Linus Pauling Institute; Lignans; Jane Higdon; Dec. 2005
- University of Maryland Medical Center; Breast Cancer; Steven D. Ehrlich; June 16, 2010
