Fighting Breast Cancer With Flaxseeds

What are lignans?

Plant lignans are one of the four classes of phytoestrogens (isoflavones, lignans, stilbenes, coumestans), phenolic compounds that are structurally similar to the main mammalian estrogen, estradiol.¹ Plant lignans are modified by bacteria in the human digestive tract into enteroligans. It is important to recognize the role of healthy bacteria in this process, because antibiotics can destroy beneficial bacteria in the gut resulting in long-term reduction in enteroligans.² Eating commercial meats exposes us to antibiotics, as does the overuse and inappropriate prescribing by physicians.

Which foods are good sources of plant lignans?

Flaxseeds are the richest source of plant lignans, having about 8 times the lignan content of sesame seeds [note that flaxseed oil does not contain lignans - they bind to the fiber]. The other plant foods on the list have about one-tenth or less the amount of lignans as sesame seeds per serving.^2,3 Chia seeds are also a rich source of lignans, however the exact amount is still debatable, so that number will be made available at a later date.

• Flaxseeds (85.5 mg/ounce)
• Sesame seeds (11.2 mg/ounce)⁴
• Kale (curly; 1.6 mg/cup)
• Broccoli (1.2 mg/cup)

Anti-cancer effects of lignans

Enterolignans are structurally similar to estrogen and can bind to estrogen receptors – this capability allows lignans to either have weak estrogenic activity or block the actions of estrogen in the body. For this reason, plant lignans are classified as phytoestrogens, and there has been much interest in the potential contribution of lignan-rich foods to reduced risk of hormone-related cancers.^2,5 Enterolignans inhibits aromatase⁶ and estradiol production in general, lowering serum estrogen levels.⁷ Plant lignans also increase concentration of sex hormone binding globulin, which blunts the effects of estrogens.^8-10 These benefits were documented when 48 postmenopausal women consumed 7.5 g/day of ground flax seeds for 6 weeks, then 15 g for 6 weeks – and significant decreases in estradiol, estrone, and testosterone were noted with a bigger decrease in overweight and obese women.¹¹

In a mouse model, a flaxseed diet (5%, 10%) shows dose-dependent inhibition of breast tumor growth.¹² Human trials also confirmed similar beneficial effects. A double-blinded, randomized controlled trial of dietary flaxseed demonstrated dramatic protection. Women ate either a control muffin with no flax seeds imbedded or 25g flax-containing muffin starting at time of diagnosis of breast cancer for just 32-39 days until surgery. Tumor tissue analyzed at diagnosis and surgery demonstrated surprising benefits even in this short timeframe. There was a significant apoptosis (tumor cell death) and reduced cell proliferation in the flaxseed group in just the one month.¹³ Likewise women eating more flaxseeds with a documented higher serum enterolactone were found to have a 42% reduced risk of death from postmenopausal breast cancer and a dramatic (40 percent) reduction in all causes of death.^14,15 Flaxseeds are clearly super foods; even with a mediocre diet they offer powerful protection against certain types of breast cancer. Another interesting study on flax followed women for up to 10 years and found a 51% reduced risk of all-cause mortality and a 71% reduced risk of breast cancer mortality. The intake of dried beans was also associated with a 39% reduced risk of all-cause mortality.¹⁶ Endometrial and ovarian cancer have not been as extensively studied, but the few studies that have been conducted suggest a protective effect.^2,17

Bottom line; don’t forget to take your ground flax seeds (or chia seeds) every day. I sometimes forget too, but reviewing the science encourages me to remember. When used in conjunction with dietary exposure to greens, onions, mushrooms and beans, dramatic reductions in the risk of breast cancer are possible.

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Dr. Fuhrman's newest book, Super Immunity, addresses his full nutritional program to win the war against breast cancer.

References:
1. Carter P, Gray LJ, Troughton J, et al. Fruit and vegetable intake and incidence of type 2 diabetes mellitus: systematic review and meta-analysis. BMJ. 2010 Aug 18;341:c4229. Journal of Clinical Investigation (2011, March 24). High levels of dietary nitrate might in part explain the vascular benefits of diets rich in leafy greens. ScienceDaily. Retrieved March 30, 2011, from http://www.sciencedaily.com­ /releases/2011/03/110323135631.htm
2. Stringham JM, Bovier ER, Wong JC, Hammond BR Jr. The influence of dietary lutein and zeaxanthin on visual performance. J Food Sci. 2010 Jan-Feb;75(1):R24-9.
3. Higdon JV, Delage B, Williams DE, Dashwood RH. Cruciferous vegetables and human cancer risk: epidemiologic evidence and mechanistic basis. Pharmacol Res. 2007 Mar;55(3):224-36. Cavell BE, Syed Alwi SS, Donlevy A, et al., Anti-angiogenic effects of dietary isothiocyanates: mechanisms of action and implications for human health. Biochem. Pharmacol., 2011. 81(3): p. 327-36.
4. Powolny AA, Singh SV. Multitargeted prevention and therapy of cancer by diallyl trisulfide and related Allium vegetable-derived organosulfur compounds. Cancer Lett. 2008 Oct 8;269(2):305-14.
5. Pierini R, Gee JM, Belshaw NJ, et al. Flavonoids and intestinal cancers. Br J Nutr. 2008 May;99 E Suppl 1:ES53-9.
6. Slimestad R, Fossen T, Vågen IM. Onions: a source of unique dietary flavonoids. J Agric Food Chem. 2007 Dec 12;55(25):10067-80.
7. Miyamoto S, Yasui Y, Ohigashi H, et al. Dietary flavonoids suppress azoxymethane-induced colonic preneoplastic lesions in male C57BL/KsJ-db/db mice. Chem Biol Interact. 2010 Jan 27;183(2):276-83. Shan BE, Wang MX, Li RQ. Quercetin inhibit human SW480 colon cancer growth in association with inhibition of cyclin D1 and survivin expression through Wnt/beta-catenin signaling pathway. Cancer Invest. 2009 Jul;27(6):604-12. Xavier CP, Lima CF, Preto A, et al. Luteolin, quercetin and ursolic acid are potent inhibitors of proliferation and inducers of apoptosis in both KRAS and BRAF mutated human colorectal cancer cells. Cancer Lett. 2009 Aug 28;281(2):162-70.
8. Ravasco P, Aranha MM, Borralho PM, et al. Colorectal cancer: Can nutrients modulate NF-kappaB and apoptosis? Clin Nutr. 2010 Feb;29(1):42-46.
9. Hong SA, Kim K, Nam SJ, et al: A case-control study on the dietary intake of mushrooms and breast cancer risk among Korean women. Int J Cancer 2008, 122:919-923. Shin A, Kim J, Lim SY, et al: Dietary mushroom intake and the risk of breast cancer based on hormone receptor status. Nutr Cancer 2010, 62:476-483. Zhang M, Huang J, Xie X, et al: Dietary intakes of mushrooms and green tea combine to reduce the risk of breast cancer in Chinese women. Int J Cancer 2009, 124:1404-1408.
10. Hara M, Hanaoka T, Kobayashi M, et al: Cruciferous vegetables, mushrooms, and gastrointestinal cancer risks in a multicenter, hospital-based case-control study in Japan. Nutr Cancer 2003, 46:138-147.
11. Chen S, Oh SR, Phung S, et al: Anti-aromatase activity of phytochemicals in white button mushrooms (Agaricus bisporus). Cancer Res 2006, 66:12026-12034.
12. Bazzano LA, Li TY, Joshipura KJ, Hu FB. Intake of fruit, vegetables, and fruit juices and risk of diabetes in women. Diabetes Care. 2008 Jul;31(7):1311-7. Hannum SM. Potential impact of strawberries on human health: a review of the science. Crit Rev Food Sci Nutr. 2004;44(1):1-17. Joseph JA, Shukitt-Hale B, Willis LM. Grape juice, berries, and walnuts affect brain aging and behavior. J Nutr. 2009 Sep;139(9):1813S-7S. Stoner GD, Wang LS, Casto BC. Laboratory and clinical studies of cancer chemoprevention by antioxidants in berries. Carcinogenesis. 2008 Sep;29(9):1665-74. Cassidy A, O'Reilly EJ, Kay C, et al: Habitual intake of flavonoid subclasses and incident hypertension in adults. Am J Clin Nutr 2011, 93:338-347. Roy S, Khanna S, Alessio HM, et al: Anti-angiogenic property of edible berries. Free Radic Res 2002, 36:1023-1031.
13. Bickford PC, Shukitt-Hale B, Joseph J. Effects of aging on cerebellar noradrenergic function and motor learning: nutritional interventions. Mech Ageing Dev. 1999 Nov;111(2-3):141-54. Krikorian R, Shidler MD, Nash TA, et al. Blueberry supplementation improves memory in older adults. J Agric Food Chem. 2010 Apr 14;58(7):3996-4000.
14. Bazzano LA, Thompson AM, Tees MT, et al. Non-soy legume consumption lowers cholesterol levels: A meta-analysis of randomized controlled trials. Nutr Metab Cardiovasc Dis 2011 Feb;21(2):94-103. Aune D, De Stefani E, Ronco A, et al. Legume intake and the risk of cancer: a multisite case-control study in Uruguay. Cancer Causes Control. 2009 Nov;20(9):1605-15.
15. O'Keefe SJ, Ou J, Aufreiter S, et al. Products of the colonic microbiota mediate the effects of diet on colon cancer risk. J Nutr. 2009 Nov;139(11):2044-8.
16. Singh PN, Fraser GE. Dietary risk factors for colon cancer in a low-risk population. Am J Epidemiol. 1998 Oct 15;148(8):761-74.
17. Aune D, De Stefani E, Ronco A, et al. Legume intake and the risk of cancer: a multisite case-control study in Uruguay. Cancer Causes Control. 2009 Nov;20(9):1605-15.
18. Nash SD, Nash DT. Nuts as part of a healthy cardiovascular diet. Curr Atheroscler Rep. 2008 Dec;10(6):529-35. Sabaté J, Ang Y. Nuts and health outcomes: new epidemiologic evidence. Am J Clin Nutr. 2009 May;89(5):1643S-1648S. Mattes RD et al. Impact of peanuts and tree nuts on body weight and healthy weight loss in adults. J Nutr. 2008 Sep;138(9):1741S-1745S. Natoli S, McCoy P. A review of the evidence: nuts and body weight. Asia Pac J Clin Nutr. 2007;16(4):588-97 19. Kendall CW, Josse AR, Esfahani A, Jenkins DJ. Nuts, metabolic syndrome and diabetes. Br J Nutr. 2010 Aug;104(4):465-73.
20. Bassett CM, Rodriguez-Leyva D, Pierce GN. Experimental and clinical research findings on the cardiovascular benefits of consuming flaxseed. Appl Physiol Nutr Metab. 2009 Oct;34(5):965-74. Webb AL, McCullough ML. Dietary lignans: potential role in cancer prevention. Nutr Cancer. 2005;51(2):117-31. Saarinen NM, Wärri A, Airio M, et al. Role of dietary lignans in the reduction of breast cancer risk. Mol Nutr Food Res. 2007 Jul;51(7):857-66. Coulman KD, Liu Z, Hum WQ, et al. Whole sesame seed is as rich a source of mammalian lignan precursors as whole flaxseed. Nutr Cancer. 2005;52(2):156-65. Shahidi F, Liyana-Pathirana CM, Wall DS. Antioxidant activity of white and black sesame seeds and their hull fractions. Food Chemistry 2006;99(3): 478-483.