Did you know that flaxseeds have potent anticancer effects?
Researchers from the University of Toronto recently reviewed a number of studies on flaxseeds and flaxseed oil, as well as lignans found in flaxseed.
Lignans are a class of phytoestrogens or plant estrogens that also act as antioxidants. Other foods also contain lignans - including sesame, sunflower and pumpkin seeds, grains such as rye, barley, wheat and oats as well as broccoli and beans - but flaxseeds have hundreds of times the amount of lignans as any of the others.
Flaxseeds and lignan intake have been associated with reduced breast cancer risk, particularly in postmenopausal women. Lignans reduce breast cancer mortality by 33-70% and all-cause mortality by 40-53%.
Further, diets containing 10% flaxseeds have been shown to increase the effectiveness of Tamoxifen, the usual anti-estrogen therapy for hormone receptor-positive breast cancer in pre- and post-menopausal women.
Clinical trials show that taking 25 grams per day of flaxseeds - containing 50 milligrams of lignans - for 32 days reduces tumor growth in breast cancer patients.
Specifically, flaxseeds protect women from breast cancer in these six ways:
- Lowering tumor cell proliferation - lignans are broken down by bacteria in the gut into 2 estrogen-like compounds that circulate through the liver. These compounds have been proven to prevent breast tumor growth in animal studies.
- Blocking tumor blood supply - all tumors need new blood vessels (known as angiogenesis) to supply oxygen and nutrients for growth. Flaxseeds block the growth factor needed to stimulate angiogenesis.
- Lowering estrogen production - lignans block an enzyme involved in production of estrogen, lowering estrogen production. This may be beneficial in breast cancer, because high estrogen levels have been linked to breast cancer growth.
- Blocking estrogen receptors - lignans are believed to be hundreds of times weaker than human estrogen, but they dock on estrogen receptors and prevent the activity of stronger cancer stimulating human and synthetic estrogens.
- Generating more protective estrogen metabolites - estrogen is broken down in the liver into three different metabolites. Two have been linked to the growth of breast cancer cells, but the third is considered protective. Lignans seem to trigger production of more of the protective metabolite relative to the others.
- Lowering the risk of metastasis - in one animal study, a diet rich in flaxseeds reduced the incidence of metastasis by 82% compared to the control group.
Many of these studies show that consumption of just 25 grams or 2.5 tablespoons of flaxseeds daily is effective against breast cancer.
You can introduce flaxseeds into your diet by adding 1-2 tablespoons of freshly ground flaxseeds to cereals, smoothies, yogurt or salads. You can also add it to baked breads and muffins. Aim for 2-4 tablespoons per day