Flaxseed is a rich source of lignans, which are phytoestrogens. Phytoestrogens are plant-derived compounds which exert estrogen-like effects in your body. They are attributed with a variety of health benefits, including a reduction in your risks for cancer and heart disease. A 2009 study in "Molecular Nutrition and Food Research" even suggested that lignans and other phytoestrogens could be useful for treating estrogen-dependent diseases, such as breast cancer. However, phytoestrogens are not approved for treating any disease or condition.
Conversion of Flax Lignans to Mammalian Lignans
According to a 2002 review in "Journal of Chromatography," the lignans from flaxseed are converted to mammalian lignans by bacteria in your gut. The two main byproducts of this conversion, enterolactone and enterodiol, possess estrogen-balancing properties, like many other phytoestrogens. The review's authors suggested that a high production of mammalian lignans in your intestine might confer protection from breast cancer in women or prostate cancer in men. Lignans are currently not approved for treating or preventing these diseases.
Lignans Regulate Estrogen Signaling
Many cells in your body possess estrogen receptors, including those in the breast, brain, ovary and testis. Stimulation of these receptors by estrogen helps to guide development, maturation and behavior. However, overstimulation of these same receptors is believed to contribute to premenstrual syndrome and even some serious illnesses, such as breast and prostate cancer. A 2011 "Cancer Research" study demonstrated that flax lignans down-regulate estrogen's effects in breast tumors. However, flax has not been shown to prevent or cure breast cancer.
Lignans in Menopause
Phytoestrogens are popular alternative remedies for treating hot flashes, vaginal dryness and other menopausal symptoms. In addition, some researchers have voiced the hope that lignans could reduce the risk for breast cancer in elderly women. A 2009 "Nutrition and Cancer" study showed that flax lignans lowered the blood levels of hormones that play a role in promoting breast cancer, but another study in a 2009 edition of "The Journal of Nutrition" demonstrated that consumption of flax lignans at a daily dose of 46 mg did not alleviate menopausal symptoms.
Considerations
As demonstrated in the April 2010 issue of "BMC Microbiology," flax lignans have garnered a great deal of attention for their potential in treating a variety of hormone-dependent conditions, including breast, colon and prostate cancers, osteoporosis, cardiovascular disease and menopause. Although research is promising, there is insufficient evidence to support the use of flax lignans for treating or preventing any illness or condition. If you think flax lignans would be beneficial for you, speak with your doctor.
References
- "Molecular Nutrition and Food Research"; Dietary Sources of Lignans and Isoflavones Modulate Responses to Estradiol in Estrogen Reporter Mice; P.E. Penttinen-Damdimopoulou, et al.; August 2009
- "Journal of Chromatography"; Mammalian Phytoestrogens: Enterodiol and Enterolactone; L.Q. Wang; September 2002
- "Cancer Research"; Tamoxifen, Flaxseed, and the Lignan Enterolactone Increase Stroma- and Cancer Cell-Derived IL-1Ra and Decrease Tumor Angiogenesis in Estrogen-Dependent Breast Cancer; G. Lindahl, et al.; January 2011
- "Nutrition and Cancer"; Effect of Dietary Flaxseed on Serum Levels of Estrogens and Androgens in Postmenopausal Women; S.R. Sturgeon, et al.; 2008
- "The Journal of Nutrition"; Consumption of Flaxseed-Rich Food Is Not More Effective than a Placebo in Alleviating the Climacteric Symptoms of Postmenopausal Women; R.L. Simbalista, et al.; February 2010
- "BMC Microbiology"; Production of Enterodiol from Defatted Flaxseeds through Biotransformation by Human Intestinal Bacteria; C.Z. Wang, et al.; April 2010
