Model of Flax action in the prevention and suppression of cancer: omega-3 fatty acids in the seed germ and phytoestrogen lignan in the seed hull act synergistically on separate pathwaysAs research into the role of nutrition in cancer continues, it is increasingly evident that nutrition plays a major role in cancer. It has been estimated by the American Institute for Cancer Research that 30-40 percent of all cancers can be prevented by appropriate diets, physical activity and maintenance of appropriate body weight . Obesity, nutrient sparse foods such as concentrated sugars and refined flour products, low fiber intake, consumption of red meat, and imbalance of omega 3 (OM-3FA) and omega 6 (OM-6FA) fats all contribute to excess cancer risk. OM-3FA and OM-6FA are polyunsaturated fats that are referred to as essential fatty acids because they cannot be synthesized by mammals and must be obtained from the diet.
The OM-3FAs a-linolenic acid (ALA; 18:3n:3), eicosapentaenoic acid (EPA; 20:5n:3), and docosahexaenoic acid (DHA; 22:6n:3) have been shown in animal studies to protect from cancer, while the OM-6FAs linoleic acid (LA; 18:2n:6), and arachidonic acid(AA; 20:4n:6) have been shown to be cancer promoting fats. EPA and DHA are both found primarily in oily cold-water fish such as tuna, salmon, and mackerel. ALA is found primarily in dark green leafy vegetables, flax seed oils, and certain vegetable oils. GI enzymes convert ALA to EPA and DHA, and all three OM-3FAs are important to human health. Excessive amounts of OM-6FAs and a very high OM-6FA/OM-3FA ratio have been linked with pathogenesis of many diseases, including cardiovascular disease, cancer, and inflammatory and autoimmune diseases. The ratio of OM-6FA to OM-3FA in modern diets is approximately 15:1, whereas ratios of 2:1 to 4:1 have been associated with reduced mortality from cardiovascular disease, suppressed inflammation, and decreased risk of cancer. OM-3FAs reduce inflammation and OM-6FAs tend to promote inflammation. OM-3FA have been shown to have a protective effect against ovarian cancer in population based studies. In fact, OM-3FA have been proposed as possible non-toxic chemopreventative agents for epithelial ovarian cancer. Recently, OM-3FA were shown to inhibit the proliferation, induce apoptosis, and suppress VEGF production in ovarian cancer cells in vitro—biological endpoints for chemopreventative trials. Moreover, it is clear that OM-3FAs have demonstrated significant anti-proliferative effects in vitro in many cancer cell lines, most notably breast and colon. Clearly there is an important need for preclinical studies to definitively evaluate the efficacy of OM-3FA as a chemopreventative regimen for ovarian cancer.