Ten Strategies for Preventing Breast Cancer
Breast cancer is the most common form of cancer among women and cancer is the second leading cause of death in women, following heart disease. There are different types of breast cancer and each one is complex with many contributing factors. Fortunately, there are environmental factors within our control that can help women minimize their risks for developing breast and other cancers as well as cardiovascular disease and other health issues. Follow these 10 strategies to not only help prevent breast cancer, but to also protect your current and future overall health.
1) Eat lots of green vegetables, mushrooms, and onions.
Following a high-nutrient diet rich in G-BOMBS, as described in my book Super Immunity, protects against many chronic diseases, breast cancer included. Green vegetables and mushrooms are the most powerful anti-breast cancer foods. Take note that a vegetarian diet does not show protection against breast cancer as much as a diet rich in green vegetables, beans, mushrooms, onions, berries, nuts and seeds. It is the phytochemical nutrient density and diversity of the diet that offers the most dramatic protection against cancer, not merely the avoidance of meat or fat.1-5 Vegetables and fruits have been consistently associated with both reduced risk of breast cancer and improved survival of breast cancer patients.1,3,6-8 Cruciferous vegetables contain powerful anti-cancer compounds that halt the growth of breast cancer cells and promote excretion of estrogen.2,9,10 Mushrooms block tumor growth and have anti-estrogenic activity—regular consumption of mushrooms—as little as one mushroom per day—has been shown to decrease breast cancer risk by up to 60-70%.4,5,11 Organosulfur compounds in onions and garlic also prevent the development of cancers by detoxifying carcinogens, halting cancer cell growth, and preventing tumors from obtaining a blood supply.12
2) Use one tablespoon of ground flax or chia seed daily.
Flax and chia seeds are the richest sources of lignans, phytochemicals with anti-estrogenic effects which also inhibit cell growth in breast tumors.13,14 In fact, in one notable study of women who were scheduled to have breast tumors removed, half ate a flax-containing muffin and the other half ate a control muffin daily, for 32-39 days until surgery. Their tumor tissue was analyzed, and even in this short timeframe, there was significant apoptosis (tumor cell death) and reduced cell proliferation of tumor cells in the flaxseed group.15
3) Reduce consumption of animal protein.
Consuming more protein and especially dairy products raises blood levels of insulin-like growth factor 1 (IGF-1), and elevated IGF-1 levels have been associated with increased in breast cancer risk in many studies.16-24 Higher fish consumption in women has also been linked to higher rates of breast cancer.25 Agricultural and industrial carcinogens, such as dioxins, accumulate in fatty tissues. Humans’ primary mode of exposure to these dangerous chemicals is from meat, poultry, fish, and dairy fat.26
4) Don’t eat fried foods or well-done meats.
Steaming, wokking, and making vegetable soups should be the major extent of cooking. High temperature dry cooking produces potentially carcinogenic compounds—acrylamide (formed in starchy foods like French fries) and heterocyclic amines (formed in meats).27-29 For example, chicken cooked at high temperatures is known to contain a heterocyclic amine called PhiP, which is a breast carcinogen.30-32
5) Choose supplements without synthetic folic acid.
Make sure your multivitamin and other supplements do not contain folic acid. Also do not use nutritional yeast fortified with folic acid. Folic acid is found in most multivitamins and prenatal vitamins, and is associated with increased risk of breast cancer, whereas folate from natural food sources is associated with decreased risk.33-36 Folic acid is synthetic, not found in nature, whereas green vegetables are loaded with folate (the real thing). Also important regarding supplements: maintain healthy vitamin D levels and take a DHA+EPA supplement daily. Three-quarters of women who have breast cancer are vitamin D deficient, and maintaining sufficient blood vitamin D levels can decrease risk of breast cancer by up to 45%.37,38 Greater omega-3 fatty acid consumption is associated with reduced cancer incidence. EPA has anti-inflammatory effects and DHA has been found to block tumor angiogenesis and tumor cell growth.39-42
6) Exercise at least three hours a week and maintain a lean body with little body fat.
An analysis of 73 different studies concluded that women with high levels of physical activity reduced their risk of breast cancer by 25%.43,44 Maintaining a healthy weight is also extremely important, since 17% of breast cancer cases have been attributed to obesity alone.45
7) Do not drink alcohol.
More than fifty studies have been conducted on the influence of alcohol on breast cancer risk. Even light drinking (one or fewer alcoholic drinks per day) is associated with increased risk; for example, data from the Nurses’ Health Study suggested that women consuming 3-6 alcoholic drinks weekly increased their breast cancer risk by 15% compared to non-drinkers.46-47 In breast cancer survivors, drinking 3-4 alcoholic beverages per week increased the risk of recurrence by 34%.48
8) Do not smoke.
Breast carcinogens have been identified in cigarette smoke, and they are known to enter the bloodstream via the lungs and travel to breast tissue, putting smokers at risk.49
9) Limit your exposure to estrogen.
Cumulative exposure to estrogen is known to be a risk factor for breast cancer.50,51 As such, women who have used hormone replacement therapy (HRT) are at risk, and that risk increases with increasing duration of HRT.52 The use of higher-dose estrogen-containing contraceptives is also associated with increased risk.53,54 Women can also be exposed to estrogen via production by excess fat tissue, or environmental sources such as endocrine-disrupting chemicals (like BPA and phthalates). Maintaining a healthy weight and avoiding endocrine disruptors when possible helps to limit estrogen exposure. In addition, a vegetable-based, fiber-rich diet reduces circulating estrogen levels, because fiber binds up estrogen in the digestive tract, accelerating its removal from the body.55-57
10) Have babies and nurse them as long as you can.
Having children before the age of 24 and having multiple children are both protective against breast cancer.58 Breastfeeding also contributes to risk reduction, in part by reducing estrogen exposure—longer duration of breastfeeding confers more protection.59
1. Gandini S, Merzenich H, Robertson C, et al: Meta-analysis of studies on breast cancer risk and diet: the role of fruit and vegetable consumption and the intake of associated micronutrients. Eur J Cancer 2000;36:636-646.
2. Higdon J, Delage B, Williams D, et al: Cruciferous vegetables and human cancer risk: epidemiologic evidence and mechanistic basis. Pharmacol Res 2007;55:224-236.
3. Zhang CX, Ho SC, Chen YM, et al: Greater vegetable and fruit intake is associated with a lower risk of breast cancer among Chinese women. Int J Cancer 2009;125:181-188.
4. 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.
5. 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.
6. Boggs DA, Palmer JR, Wise LA, et al: Fruit and Vegetable Intake in Relation to Risk of Breast Cancer in the Black Women's Health Study. Am J Epidemiol 2010.
7. McEligot AJ, Largent J, Ziogas A, et al: Dietary fat, fiber, vegetable, and micronutrients are associated with overall survival in postmenopausal women diagnosed with breast cancer. Nutr Cancer 2006;55:132-140.
8. Pierce JP, Stefanick ML, Flatt SW, et al: Greater survival after breast cancer in physically active women with high vegetable-fruit intake regardless of obesity. J Clin Oncol 2007;25:2345-2351.
9. Watercress may 'turn off' breast cancer signal [http://www.soton.ac.uk/mediacentre/news/2010/sep/10_94.shtml ]
10. Rose P, Huang Q, Ong CN, et al: Broccoli and watercress suppress matrix metalloproteinase-9 activity and invasiveness of human MDA-MB-231 breast cancer cells. Toxicol Appl Pharmacol 2005;209:105-113.
11. 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.
12. Powolny A, Singh S: Multitargeted prevention and therapy of cancer by diallyl trisulfide and related Allium vegetable-derived organosulfur compounds. Cancer Lett 2008;269:305-314.
13. Sturgeon SR, Heersink JL, Volpe SL, et al: Effect of dietary flaxseed on serum levels of estrogens and androgens in postmenopausal women. Nutr Cancer 2008;60:612-618.
14. Thompson LU, Chen JM, Li T, et al: Dietary flaxseed alters tumor biological markers in postmenopausal breast cancer. Clin Cancer Res 2005;11:3828-3835.
15. Thompson LU, Chen JM, Li T, et al: Dietary flaxseed alters tumor biological markers in postmenopausal breast cancer. Clin Cancer Res 2005;11:3828-3835.
16. Rinaldi S, Peeters PH, Berrino F, et al: IGF-I, IGFBP-3 and breast cancer risk in women: The European Prospective Investigation into Cancer and Nutrition (EPIC). Endocr Relat Cancer 2006;13:593-605.
17. Hankinson SE, Willett WC, Colditz GA, et al: Circulating concentrations of insulin-like growth factor-I and risk of breast cancer. Lancet 1998;351:1393-1396.
18. Lann D, LeRoith D: The role of endocrine insulin-like growth factor-I and insulin in breast cancer. J Mammary Gland Biol Neoplasia 2008;13:371-379.
19. Allen NE, Roddam AW, Allen DS, et al: A prospective study of serum insulin-like growth factor-I (IGF-I), IGF-II, IGF-binding protein-3 and breast cancer risk. Br J Cancer 2005;92:1283-1287.
20. Fletcher O, Gibson L, Johnson N, et al: Polymorphisms and circulating levels in the insulin-like growth factor system and risk of breast cancer: a systematic review. Cancer Epidemiol Biomarkers Prev 2005;14:2-19.
21. Renehan AG, Zwahlen M, Minder C, et al: Insulin-like growth factor (IGF)-I, IGF binding protein-3, and cancer risk: systematic review and meta-regression analysis. Lancet 2004;363:1346-1353.
22. Shi R, Yu H, McLarty J, et al: IGF-I and breast cancer: a meta-analysis. Int J Cancer 2004;111:418-423.
23. Sugumar A, Liu YC, Xia Q, et al: Insulin-like growth factor (IGF)-I and IGF-binding protein 3 and the risk of premenopausal breast cancer: a meta-analysis of literature. Int J Cancer 2004;111:293-297.
24. Baglietto L, English DR, Hopper JL, et al: Circulating insulin-like growth factor-I and binding protein-3 and the risk of breast cancer. Cancer Epidemiol Biomarkers Prev 2007;16:763-768.
25. Stripp C, Overvad K, Christensen J, et al: Fish intake is positively associated with breast cancer incidence rate. J Nutr 2003;133:3664-3669.
26. U.S. Environmental Protection Agency: Dioxins and Furans [http://www.epa.gov/pbt/pubs/dioxins.htm ]
27. Zheng W, Lee S-A: Well-Done Meat Intake, Heterocyclic Amine Exposure, and Cancer Risk. Nutr Cancer 2009;61:437-446.
28. Hogervorst JG, Baars BJ, Schouten LJ, et al: The carcinogenicity of dietary acrylamide intake: a comparative discussion of epidemiological and experimental animal research. Crit Rev Toxicol 2010;40:485-512.
29. Pedersen GS, Hogervorst JG, Schouten LJ, et al: Dietary acrylamide intake and estrogen and progesterone receptor-defined postmenopausal breast cancer risk. Breast Cancer Res Treat 2010;122:199-210.
30. Fu Z, Deming SL, Fair AM, et al: Well-done meat intake and meat-derived mutagen exposures in relation to breast cancer risk: the Nashville Breast Health Study. Breast Cancer Res Treat 2011.
31. Lauber SN, Gooderham NJ: The cooked meat-derived mammary carcinogen 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine promotes invasive behaviour of breast cancer cells. Toxicology 2011;279:139-145.
32. Thomson B: Heterocyclic amine levels in cooked meat and the implication for New Zealanders. Eur J Cancer Prev 1999;8:201-206.
33. Charles D, Ness AR, Campbell D, et al: Taking folate in pregnancy and risk of maternal breast cancer. BMJ 2004;329:1375-1376.
34. Kim YI: Does a high folate intake increase the risk of breast cancer? Nutr Rev 2006;64:468-475.
35. Sellers TA, Grabrick DM, Vierkant RA, et al: Does folate intake decrease risk of postmenopausal breast cancer among women with a family history? Cancer Causes Control 2004;15:113-120.
36. Stolzenberg-Solomon RZ, Chang SC, Leitzmann MF, et al: Folate intake, alcohol use, and postmenopausal breast cancer risk in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial. Am J Clin Nutr 2006;83:895-904.
37. Chen P, Hu P, Xie D, et al: Meta-analysis of vitamin D, calcium and the prevention of breast cancer. Breast Cancer Res Treat 2010;121:469-477.
38. Hines SL, Jorn HK, Thompson KM, et al: Breast cancer survivors and vitamin D: a review. Nutrition 2010;26:255-262.
39. Simopoulos AP: The importance of the omega-6/omega-3 fatty acid ratio in cardiovascular disease and other chronic diseases. Exp Biol Med (Maywood) 2008;233:674-688.
40. Blanckaert V, Ulmann L, Mimouni V, et al: Docosahexaenoic acid intake decreases proliferation, increases apoptosis and decreases the invasive potential of the human breast carcinoma cell line MDA-MB-231. Int J Oncol 2010;36:737-742.
41. Noguchi M, Rose DP, Earashi M, et al: The role of fatty acids and eicosanoid synthesis inhibitors in breast carcinoma. Oncology 1995;52:265-271.
42. Spencer L, Mann C, Metcalfe M, et al: The effect of omega-3 FAs on tumour angiogenesis and their therapeutic potential. Eur J Cancer 2009;45:2077-2086.
43. Friedenreich CM: The role of physical activity in breast cancer etiology. Semin Oncol 2010;37:297-302.
44. American Institute for Cancer Research: The Exercise Factor [http://www.aicr.org/site/News2?page=NewsArticle&id=7651&news_iv_ctrl=0&abbr=pub_ ]
45. American Institute for Cancer Research. New Estimate: Excess Body Fat Alone Causes over 100,000 Cancers in US Each Year [http://www.aicr.org/site/News2/153571380?abbr=pr_&page=NewsArticle&id=17333&news_iv_ctrl=1102 ]
46. Chen WY, Rosner B, Hankinson SE, et al: Moderate alcohol consumption during adult life, drinking patterns, and breast cancer risk. JAMA 2011;306:1884-1890.
47. Boyle P, Boffetta P: Alcohol consumption and breast cancer risk. Breast Cancer Res 2009;11 Suppl 3:S3.
48. Kwan ML: Alcohol consumption and breast cancer recurrence and survival among women with early-stage breast cancer. In San Antonio Breast Cancer Symposium; 2009.
49. Terry PD, Rohan TE: Cigarette smoking and the risk of breast cancer in women: a review of the literature. Cancer Epidemiol Biomarkers Prev 2002;11:953-971.
50. Key T, Appleby P, Barnes I, et al: Endogenous sex hormones and breast cancer in postmenopausal women: reanalysis of nine prospective studies. J Natl Cancer Inst 2002;94:606-616.
51. Eliassen AH, Missmer SA, Tworoger SS, et al: Endogenous steroid hormone concentrations and risk of breast cancer among premenopausal women. J Natl Cancer Inst 2006;98:1406-1415.
52. Breast cancer and hormone replacement therapy: collaborative reanalysis of data from 51 epidemiological studies of 52,705 women with breast cancer and 108,411 women without breast cancer. Collaborative Group on Hormonal Factors in Breast Cancer. Lancet 1997;350:1047-1059.
53. Aubertin-Leheudre M, Gorbach S, Woods M, et al: Fat/fiber intakes and sex hormones in healthy premenopausal women in USA. J Steroid Biochem Mol Biol 2008;112:32-39.
54. Zhu H, Lei X, Feng J, et al: Oral contraceptive use and risk of breast cancer: a meta-analysis of prospective cohort studies. Eur J Contracept Reprod Health Care 2012;17:402-414.
55. Beaber EF, Buist DS, Barlow WE, et al: Recent oral contraceptive use by formulation and breast cancer risk among women 20 to 49 years of age. Cancer Res 2014;74:4078-4089.
56. Aubertin-Leheudre M, Hamalainen E, Adlercreutz H: Diets and hormonal levels in postmenopausal women with or without breast cancer. Nutr Cancer 2011;63:514-524.
57. Goldin BR, Adlercreutz H, Gorbach SL, et al: Estrogen excretion patterns and plasma levels in vegetarian and omnivorous women. N Engl J Med 1982;307:1542-1547.
58. Russo J, Moral R, Balogh GA, et al: The protective role of pregnancy in breast cancer. Breast Cancer Res 2005;7:131-142.
59. Breast cancer and breastfeeding: collaborative reanalysis of individual data from 47 epidemiological studies in 30 countries, including 50302 women with breast cancer and 96973 women without the disease. Lancet 2002;360:187-195.