Foods, Health and Disease

Fighting Breast Cancer with Flax and Chia Seeds

flaxandchiaseeds

Fighting breast cancer with flax and chia seeds

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 3 times the lignan content of chia seeds and 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

  • Flaxseeds (85.5 mg/ounce)
  • Chia seeds (32 mg/ounce)4
  • Sesame seeds (11.2 mg/ounce)5
  • 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, 6 Enterolignans inhibits aromatase7 and estradiol production in general, lowering serum estrogen levels.8 Plant lignans also increase concentration of sex hormone binding globulin, which blunts the effects of estrogens.9-11 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.12

In a mouse model, a flaxseed diet (5%, 10%) shows dose-dependent inhibition of breast tumor growth.13 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.14 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.15, 16 Flaxseeds are clearly super foods; even with a mediocre diet they offer powerful protection against 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.17 Endometrial and ovarian cancer have not been as extensively studied, but the few studies that have been conducted suggest a protective effect.2, 18

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.

References: 1. Mense SM, Hei TK, Ganju RK, et al: Phytoestrogens and breast cancer prevention: possible mechanisms of action. Environ Health Perspect 2008;116:426-433. 2. Higdon J: Lignans. In An Evidence-Based Approach to Dietary Phytochemicals. New York: Thieme; 2006: 155-161 3. Milder IE, Arts IC, van de Putte B, et al: Lignan contents of Dutch plant foods: a database including lariciresinol, pinoresinol, secoisolariciresinol and matairesinol. Br J Nutr 2005;93:393-402. 4. Nemes SM, Orstat V: Evaluation of a Microwave-Assisted Extraction Method for Lignan Quantification in Flaxseed Cultivars and Selected Oil Seeds. Food Analytical Methods 2012;5:551-563. 5. 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;52:156-165. 6. Adlercreutz H: Lignans and human health. Crit Rev Clin Lab Sci 2007;44:483-525. 7. Adlercreutz H, Bannwart C, Wahala K, et al: Inhibition of human aromatase by mammalian lignans and isoflavonoid phytoestrogens. J Steroid Biochem Mol Biol 1993;44:147-153. 8. Brooks JD, Thompson LU: Mammalian lignans and genistein decrease the activities of aromatase and 17beta-hydroxysteroid dehydrogenase in MCF-7 cells. J Steroid Biochem Mol Biol 2005;94:461-467. 9. Adlercreutz H, Mousavi Y, Clark J, et al: Dietary phytoestrogens and cancer: in vitro and in vivo studies. J Steroid Biochem Mol Biol 1992;41:331-337. 10. Adlercreutz H, Hockerstedt K, Bannwart C, et al: Effect of dietary components, including lignans and phytoestrogens, on enterohepatic circulation and liver metabolism of estrogens and on sex hormone binding globulin (SHBG). J Steroid Biochem 1987;27:1135-1144. 11. Low YL, Dunning AM, Dowsett M, et al: Phytoestrogen exposure is associated with circulating sex hormone levels in postmenopausal women and interact with ESR1 and NR1I2 gene variants. Cancer Epidemiol Biomarkers Prev 2007;16:1009-1016. 12. 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. 13. Chen J, Power KA, Mann J, et al: Flaxseed alone or in combination with tamoxifen inhibits MCF-7 breast tumor growth in ovariectomized athymic mice with high circulating levels of estrogen. Exp Biol Med (Maywood) 2007;232:1071-1080. 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. Buck K, Vrieling A, Zaineddin AK, et al: Serum enterolactone and prognosis of postmenopausal breast cancer. J Clin Oncol 2011;29:3730-3738. 16. Buck K, Zaineddin AK, Vrieling A, et al: Estimated enterolignans, lignan-rich foods, and fibre in relation to survival after postmenopausal breast cancer. Br J Cancer 2011;105:1151-1157. 17. McCann SE, Thompson LU, Nie J, et al: Dietary lignan intakes in relation to survival among women with breast cancer: the Western New York Exposures and Breast Cancer (WEB) Study. Breast Cancer Res Treat 2010;122:229-235. 18. Bandera EV, King M, Chandran U, et al: Phytoestrogen consumption from foods and supplements and epithelial ovarian cancer risk: a population-based case control study. BMC Womens Health 2011;11:40.

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Archived Article

Diets and Weight Loss

Nuts and Seeds for a Healthy Weight

nutsandseeds

Nuts and Seeds for a Healthy Weight and a Long Life

 

Nuts and seeds are healthful, natural foods that are full of beneficial nutrients and phytochemicals. Although the myth that nuts and seeds are fattening has persisted, the research suggests that nuts are actually beneficial for weight loss. In any case, it’s not the fat content of a diet that makes it healthy, it’s the nutrient content. And based on their nutrient content, nuts are a health-promoting source of calories.

Nuts and seeds are nutritionally important. Nuts and seeds contain a spectrum of micronutrients including LDL cholesterol-lowering phytosterols; circulation-promoting arginine; minerals, including potassium, calcium, magnesium, and selenium; and antioxidants, including flavonoids, resveratrol, tocopherols (vitamin E), and carotenoids.

Eating nuts and seeds reduces the risk of cardiovascular disease Epidemiological studies have consistently shown that nut consumption is beneficial for heart health. Eating five or more servings of nuts per week is estimated to reduce the risk of coronary heart disease by 35%.1 Eating nuts and seeds protects against sudden cardiac death and reduces cholesterol and inflammation.1-3

Nuts and seeds aid weight loss. Someone who is trying to lose weight should not be trying to avoid nuts; in fact, in obese individuals, adding nuts to the diet aided in weight loss and also improved insulin sensitivity, which could help to prevent or reverse diabetes.4 Nonetheless, nuts should not be eaten to excess. Nuts and seeds are high in nutrients but also high in calories, so they should be eaten with consideration for one’s caloric needs. One ounce daily is usually appropriate for women trying to lose weight and 1.5 – 2 ounces for overweight men. Nuts and seeds of course should be eaten in larger amounts for the slim, highly physically active people who could use the extra calories.

Nut consumption may enhance lifespan. In the Adventist Health Study, a number of lifestyle factors were found to be associated with longevity. Those who had a high level of physical activity, followed a vegetarian diet, and ate nuts frequently lived on average 8 years longer than those who did not share those habits.5 Similarly in the Nurses’ Health Study, nut consumption was identified as a dietary factor associated with reduced risk of death from cardiovascular disease and cancers.6 New research continues to confirm these observations.7

Each nut and seed has a unique nutritional profile that lends unique health benefits:

  • Almonds are rich in antioxidants. In one study, people ate either almonds or a snack with a similar fat profile each day for 4 weeks, and the subjects who ate almonds showed reduced oxidative stress markers.8
  • Walnuts. Diabetics who ate walnuts daily for 8 weeks experienced an enhanced ability of the blood vessels to dilate, indicating better blood pressure regulation.9 There is also evidence that walnuts may protect against breast cancer.10
  • Pistachios and Mediterranean pine nuts have the highest plant sterol content of all the nuts; plant sterols are structurally similar to cholesterol, and help to lower cholesterol levels.11 Pistachios reduce inflammation and oxidative stress as well as cholesterol.12-14
  • Mediterranean pine nuts contain a specific type of fatty acid that has been shown to curb appetite by increasing hormones that produce satiety signals.15
  • Flax, hemp, and chia seeds are extremely rich sources of omega-3 fatty acids, and hemp seeds are especially high in protein, making them a helpful food for athletes.
  • Pumpkin seeds are rich in iron, calcium, and phytochemicals, and may help to prevent prostate cancer.16
  • Sesame seeds have the greatest amount of calcium of any food in the world, and provide abundant amounts of vitamin E and contain a lignan called sesamin; lignan-rich foods may protect against breast cancer.17-19

Nuts and seeds are best eaten raw. Nuts and seeds should be eaten raw or only lightly toasted. Roasting nuts and seeds forms a potentially harmful compound called acrylamide, and reduces the amounts of minerals and amino acids.

Also remember that eating nuts and seeds with leafy greens can enhance the body’s absorption of fat-soluble nutrients from the greens, so a nut-based salad dressing is an excellent way to absorb more nutrients from your salads.20

References:

  1. Kris-Etherton PM, Hu FB, Ros E, et al: The role of tree nuts and peanuts in the prevention of coronary heart disease: multiple potential mechanisms. J Nutr 2008;138:1746S-1751S. 2. Salas-Salvado J, Casas-Agustench P, Murphy MM, et al: The effect of nuts on inflammation. Asia Pac J Clin Nutr 2008;17 Suppl 1:333-336. 3. Ros E: Nuts and novel biomarkers of cardiovascular disease. Am J Clin Nutr 2009;89:1649S-1656S. 4. Rajaram S, Sabate J: Nuts, body weight and insulin resistance. Br J Nutr 2006;96 Suppl 2:S79-86. 5. Fraser GE, Shavlik DJ: Ten years of life: Is it a matter of choice? Arch Intern Med 2001;161:1645-1652. 6. Baer HJ, Glynn RJ, Hu FB, et al: Risk factors for mortality in the nurses’ health study: a competing risks analysis. Am J Epidemiol 2011;173:319-329. 7. Guasch-Ferre M, Bullo M, Martinez-Gonzalez MA, et al: Frequency of nut consumption and mortality risk in the PREDIMED nutrition intervention trial. BMC Med 2013;11:164. 8. Jenkins DJ, Kendall CW, Marchie A, et al: Almonds reduce biomarkers of lipid peroxidation in older hyperlipidemic subjects. J Nutr 2008;138:908-913. 9. Ma Y, Njike VY, Millet J, et al: Effects of walnut consumption on endothelial function in type 2 diabetic subjects: a randomized controlled crossover trial. Diabetes Care 2010;33:227-232. 10.  Eurekalert! Walnuts slow prostate tumors in mice: UC Davis research shows walnuts affect genes related to tumor growth March 22, 2010 edition; 2010. 11. Ellegard LH, Andersson SW, Normen AL, et al: Dietary plant sterols and cholesterol metabolism. Nutr Rev 2007;65:39-45. 12. Kay CD, Gebauer SK, West SG, et al: Pistachios increase serum antioxidants and lower serum oxidized-LDL in hypercholesterolemic adults. J Nutr 2010;140:1093-1098. 13. Kocyigit A, Koylu AA, Keles H: Effects of pistachio nuts consumption on plasma lipid profile and oxidative status in healthy volunteers. Nutrition, metabolism, and cardiovascular diseases : NMCD 2006;16:202-209. 14. Sari I, Baltaci Y, Bagci C, et al: Effect of pistachio diet on lipid parameters, endothelial function, inflammation, and oxidative status: a prospective study. Nutrition 2010;26:399-404. 15. Pasman WJ, Heimerikx J, Rubingh CM, et al: The effect of Korean pine nut oil on in vitro CCK release, on appetite sensations and on gut hormones in post-menopausal overweight women. Lipids in Health and Disease 2008;7:10. 16. Hong H, Kim CS, Maeng S: Effects of pumpkin seed oil and saw palmetto oil in Korean men with symptomatic benign prostatic hyperplasia. Nutr Res Pract 2009;3:323-327. 17. 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. 18. Buck K, Vrieling A, Zaineddin AK, et al: Serum enterolactone and prognosis of postmenopausal breast cancer. J Clin Oncol 2011;29:3730-3738. 19. Higdon J: Lignans. In An Evidence-Based Approach to Dietary Phytochemicals. New York: Thieme; 2006: 155-161 20. Brown MJ, Ferruzzi MG, Nguyen ML, et al: Carotenoid bioavailability is higher from salads ingested with full-fat than with fat-reduced salad dressings as measured with electrochemical detection. Am J Clin Nutr 2004;80:396-403.