By Barry Sears
Breast cancer accounts for more than 25 percent of all female cancers. Breast cancer is also strongly linked to obesity. This means as our obesity crisis accelerates, we can expect breast cancer rates to follow. The reason that breast cancer and obesity are linked is due to cellular inflammation caused by the diet. Simply stated, this means a diet rich in refined carbohydrates, low in fruits and vegetables, and high in vegetable oils rich in omega-6 fatty acids is a sure-fire prescription for increasing the likelihood of developing both obesity and ultimately breast cancer. The biochemistry is complex, as I explain in my newest book, “Toxic Fat,” but simply stated, omega-6 fatty acids make you fat and increase the likelihood of breast cancer, whereas omega-3 fatty acids make you thin and decrease the likelihood of breast cancer.
I have always recommended an anti-inflammatory diet (like the Zone Diet), consisting primarily of low-glycemic carbohydrates (vegetables and fruits) balanced at every meal with adequate protein and dramatically limiting your intake of vegetable oils that are rich in omega-6 fatty acids. Unfortunately, it is easier to change your religion than to change your diet. So if that is too hard to implement, then try this simpler change. Just take a supplement of purified fish oil every day. This dietary change only takes 15 seconds a day. Of course, the question is how much? A research article in the May 2010 issue of the American Journal of Clinical Nutrition begins to answer that question. Subjects at high risk of developing breast cancer were given various doses of omega-3 fatty acids ranging from 1 gram to 7 grams per day for six months. Although the blood levels of omega-3 fatty acids stabilized after 30 days, the amount of the omega-3 fatty acids in the breast tissue continued to increase in a dose-dependent manner for the next six months. This means the highest omega-3 fatty acid dose has the greatest impact in changing the fatty acid composition in the breast. Earlier research indicated that the importance of the omega-6 to omega-3 fatty acids ratio in the breast tissue is pretty clear from animal studies: The higher the omega-3 content of the breast tissue, the lower the risk of developing breast cancer. From this new study, it appears that 5-7 grams per day of purified omega-3 fatty acids are required to really change the levels of the fatty acid composition in the breast tissue of high-risk women. Perhaps not too surprisingly these results are very close to my recommendations for omega-3 fatty acids that I made in 2002 in my book “The OmegaRx Zone.”
It should also be pointed out that the researchers in this study did not have a placebo group using omega-6 fatty acids because of the risk of increasing the likelihood of turning on inflammatory genes that might lead to the development of breast cancer in these high-risk subjects. If these researchers were afraid of omega-6 fatty acids found in common vegetable oils, then so should you. Simply replace your vegetable oils with extra-virgin olive oil that is low in omega-6 fatty acids and take your fish oil rich in omega-3 fatty acids. That’s a dietary change everyone can easily make.
Lee DY et al. “Omega-3 fatty acid supplements in women at high risk of breast cancer have dose-dependent effects on breast adipose tissue fatty acid composition.” Am J Clin Nutr 91: 1185-1194 (2010)
Sears B. Toxic Fat. Thomas Nelson. Nashville, TN (2008)
Bagga D et al. “Long-chain n-3-to-n-6 polyunsaturated fatty acid ratios in breast cancer adipose tissue from women with and without breast cancer.” Nutr Cancer 42: 180-185 (2002)
Sears B. The OmegaRx Zone. Regan Books. New York, NY (2002)