Breast Cancer and Flax Seed

flas seeds

Dietary flaxseed, when used with soy isolates in animal studies, stops the growth-promoting effects of soy isolate on breast cells. It reduces tumor growth in patients with breast cancer.

In studies on mice, dietary flaxseed inhibited the growth of human estrogen-dependent breast cancer and strengthened the effect of tamoxifen on inhibiting tumor growth. When combined with tamoxifen, it decreased cyclin D1 (which promotes cell division), estrogen receptor alpha (which binds to the strong estrogens), human epidermal growth factor receptor 2 (promotes growth), and insulin-like growth factor I receptor in tumour cells (a strong hormonal link to breast cancer).

When mice consumed a diet containing 10% flaxseed, a 45% reduction in overall metastases and an 82% reduction in lung metastases occurred relative to a control group. Levels of insulin-like growth factor 1 and epithelial growth factor receptor in primary tumors was lower in the group of mice that consumed flaxseed. Studies on mice found that if female mice consumed flaxseed or its lignans while breastfeeding their young, chemically induced breast cancers were decreased in the offspring, suggesting that exposure to lignans at this early stage of mammary gland development reduces susceptibility to breast cancer later in life without adverse effects.

Dietary flaxseed can lower serum levels of estradiol, estrone and testosterone, especially in overweight women. Dietary flaxseed decreases vascular endothelial growth factor (VEGF) which otherwise acts to stimulate the formation of a blood supply to a developing tumour (angiogenesis).

Alpha linolenic acid, an Omega 3 oil found in flaxseed, decreases the activity of HER2/neu oncoprotein, and hence deters breast cancer tumour growth. It acts synergistically with Herceptin, improving the response to this drug. (On the other hand, omega 6 oils such as sunflower, sesame, safflower, promote activity of the HER2/neu oncoprotein). Omega 9 oil such as olive oil, acts with flaxseed oil to deter activity of the HER2/ne oncoprotein. Therefore, we advise a diet with a low omega-6/omega-3 polyunsaturated fatty acid ratio (i.e. at least twice as much omega 3 (from flaxseed, algae or fish) to omega 6 oil in one’s diet).