Health Benefits Of Flaxseed Oil Articles & Resources

These derivatives, in turn, give rise in vivo to hormone-like molecules called eicosanoids. Eicosanoids are produced from both the omega 3 and omega 6 EFAs and have opposing functions that can have profound positive (omega 3) or negative (omega 6) influence on Since the early 1960's, we Americans have been deluged with omega 6 as a result of the belief at that time that diets high in saturated fats raised cholesterol and that their consumption should be reduced with the substitution of omega 6 polyunsaturated oils. Later and extending to our current time, the fat-free "craze" has further contributed to our most misunderstood nutrient group, the fats. The omega 3 EFA has all but disappeared from our 21st century, Western diet. Omega 3, to retain its disease-preventive properties, must be processed and handled like a perishable food. Dr. Simopou1ous' book (2) is an excellent and readable source for those seeking more information and knowledge about the omega 3 EFAs and the "right fats."

Phytoestorgens

Americans are currently hearing more about phytoestrogens. "Phyto" means plant and estrogen is the sex hormone that is predominate in females. People are hearing about phytoestrogens because of the increasing popularity of soy-based products. Recently, the FDA allowed a claim for reduction of the risk of heart disease for diets low in saturated fats and cholesterol that include 25 grams of soy protein a day. (8) The soybean, as it turns out, is one of the richest sources of the isoflavones, (3,21) or isoflavanoids, a class of phytoestrogen. There has been, over the past two decades, a large body of scientific research on the health benefits of soy and its isoflavones. There are a number of excellent reviews of this body of knowledge such as by Adlercreutz and Mazur (3) and Tham, et al. (4)

A growing body of scientific research is now pointing to another exciting and promising class of phytoestrogens. These are the lignans. We now know that there are two major phytoestrogen groups; the isoflavones that are found in greatest concentration in the soybean (a legume), and the lignans, found in greatest concentration in fiaxseed. It has only been in the last 12 years that the startling finding was made that flaxseed contains by far the most concentrated source of lignans. The research of Dr. Lilian Thompson of the University of Toronto reported on the study of 66 plant food sources with the finding that fiaxseed contains 75 to 800 times the amount of lignans of any other of these likely plant sources. (5) Table 2 summarizes these findings. Indeed, the discovery of lignans in the human body and the method of their isolation from flaxseed have only been known for about two decades. (6,7)

To understand how phytoestrogens arrive in the human body one must understand their origin in the plant and their subsequent metabolism. Reference to Figure 2 helps in this understanding. Both the isoflavones and fiaxseed lignans occur naturally as plant phytoestrogen precursors. (9,10) In the soybean or fiaxseed plant they are glycosidically linked to carbohydrates (a chemical Link to a sugar moiety). (11) When ingested, the plant phytoestrogens are converted to mammalian derivatives by bacterial metabolism in the colon. (12-15) These are then absorbed from the intestine, transported to the liver and then excreted in the bile (enterohepatic circulation). (16,17) At this point, they are partially reabsorbed and appear in relatively high concentrations in blood plasma and are finally eliminated from the body, in part, by renal clearance in the urine. (18,19) With this understanding of phytoestrogen source and metabolism, we can turn more specifically to consideration of the flaxseed lignans and the emerging im plications for their impact on health and on disease prevention.

Flaxseed Lignans

A little over two decades ago the principal flaxseed lignan phytoestrogens were isolated and their biological pathways and metabolic conversion in vivo were elucidated. (6,7) By far the most prevalent plant lignan was determined to be secoisolauriciresinol dyglycoside (SDG). A second plant lignan, matairesinol, was found but in concentrations many times less than SDG. (16,19,22) Plant lignan precursors, as discussed above, are converted by colonic bacteria to the mammalian (animal) lignans enterodiol (ED) from SDG, and enterolactone (EL) from matairesinol, respectively (13-15) (Figure 2). However, SDG is the significant plant lignan because it can be oxidized in vivo from ED to EL and is present in potentially significant quantities. (24-26) ED occurs in concentrations up to 7 times greater than EL, indicating the substantial conversion by in vivo oxidation of ED to EL. (9,23)

ED and EL exhibit hormone-like properties, mimicking the endogenous (natural occurring) estrogens. They have similar molecular weights and structures to those of steroids such as the estrogens (see Figure 3). Their peculiar level of biological activity functions to antagonize the body's estrogen cycle due to their ability to act either as a weak estrogen or as an antiestrogen. Current scientific research indicates it is through this dual mechanism that the mammalian lignans play a protective role in hormone-related cancer of the breast, ovary and prostate. (3,4,27-29)

Potential Health Benefits

As we have seen, the mammalian lignans function to modulate hormone-related cancer through estrogenic mechanisms. When acting as an estrogen, they function biologically in the same way but with 100 to 1000 times less potency. Because they are "weak" when compared to the body's own estrogens, they attenuate the estrogen carcinogenic effect, of particular importance in postmenopausal women. When acting as an anti-estrogen, they compete with the body's endogenous estrogens for receptor sites, thus reducing access to pathways that can lead to potentially adverse pathogenesis. (4,12,14,17,30)

Flaxseed's "Health Synergy"

Since the development of methods for isolating SDG in the 1990's (25,31) scientific studies, particularly by Thompson et al., (23,27-29,32) have shown convincingly that hormonal cancer protection is due to the lignan component of the flaxseed through their estrogen-like bioactivity. Science has also convincingly shown that the omega 3 oil fraction of flaxseed is the basis of cardiovascular protection through the mechanism of conversion in vivo to the hormone-like cell "regulator" eicosanoids. "Eicosa" signifies twenty in Greek, and the 20-carbon plus omega 3 derivative group of prostaglandins E2, leucotrienes B5 and thromboxanes A3 positively impact inflammation, vascular constriction, thrombosis and platelet aggregation. (2)

Research conducted and published since the mid-90's is slowly unlocking the health benefiting "secrets" of the three-fold disease fighting factors that are found in the remarkable flaxseed "storehouse." Curiously, this recent work also indicates that much of the earlier research using flaxseed and attributing protective effects to the omega 3 oil faction, and to a lesser extent, to the dietary fiber fraction, are actually a "health synergy" emanating from all three! Figure 4 summarizes the many health benefits of flaxseed and / or its components cited in the scientific research over the years.

One of the many examples of this "health synergy" is cardiovascular protection. The omega 3 oil derivatives regulate platelet aggregation, thrombosis (blood clotting), and vascular constriction, (2,20) soluble fiber slows down and regulates the nutrient, sugar and fat absorption into the bloodstream and contributes to weight control, while insoluble fiber binds and reduces cholesterol in the colon where it is synthesized enterohepatically (in the liver), (1) the mammalian lignans antagonize low density lipoprotein (LDL) receptor sites and inhibit the rate-limiting enzyme function in cholesterol formation. (3,4,17)

Phytochemicals for the New Millennium

Taking into consideration the above discussed "health synergy"; Table 3 summarizes the health-benefiting factors attributed to flaxseed fiber, the omega 3 EFA, and, in part or exclusively, to the flaxseed lignans by published scientific research.

Flaxseed Components and Health Benefits

Most of the studies at this current stage involve animal models. There are several promising human epidemiological studies and clinical trials. (4,17,20) However, much remains to be done in the study of the flaxseed lignans. Can they be the "Phytochemicals of the New Millennium"? There is good reason to believe they can significantly live up to this "billing."

In April of 2001, the world's largest supplier of food ingredients licensed the worldwide rights to the method and process patents for commercial production of SDG, the principal plant phytoestrogen in flaxseed. (25,26) Archer Daniels Midland (ADM) signed an exclusive agreement for flax lignan technology with The Flax Consortium, a research collaboration between Agriculture andAgri-Food Canada, the Saskatoon Research Centre, the University of Saskatchewan Technologies Inc., and Dr. William Clark of the University of Western Ontario and the London Health Sciences Centre.

The mission of The Flax Consortium, formed in 1995, has been to extract, purify and study the use of flax lignans for the prevention and treatment of diseases. The license gives ADM the exclusive worldwide right to produce and sell a flax lignan complex or purified flax lignan for use as an active ingredient in functional foods, nutraceuticals, pharmaceuticals, animal feed additives and veterinary products. (32-35) ADM has committed substantial research dollars to the task of completing toxicology studies and clinical trials, anticipating a three to five year period before these purified lignan phytochemicals will be commercially available. (36)

In the meantime, we can take advantage of the fact that these "phytochemicals for the new millennium" are provided for us by Mother Nature in flaxseed's amazing "storehouse."

Table 1

Source: Cereal Foods World 38 (10): 755-759. (1993)

Fiber Flax Oat Oat- Wheat Corn Rice
Component % Seed Bran meal Bran Bran Bran

Total Dietary Fiber 40 17 11 49 78 75
Soluble Fiber 10 8 5 5 3 4
Insoluble Fiber 30 8 6 43 76 71

Table 2

Source: Thompson, L. et al. Mammalian Lignan Production from Various
Foods. Nutr. Cancer. 16, 43-52. (1991).

Source Enterolactone Enterodiol
 (mg per 100g sample) (mg per 100g sample)

Oilseeds

 * Flaxseed Flour 11,818 40,861
 * Rapeseed 975 155
 * Soybean 693 170
 * Sunflower 201 195
 * Peanuts 105 56

Whole Cereals

 * Triticale 519 405
 * Wheat 411 79
 * Oats 251 89
 * Brown rice 169 128
 * Sorghum 199 56
 * Corn 199 31
 * Rye 69 91
 * Barley

Table 3

Flaxseed Components and Health Benefits

Health Benefiting Factor [omega]3 Lignans Fiber

Hypocholesterolemia CVD, Dbs CVD CVD
Hypolipidemia CVD, Dbs CVD
Antithrombolytic CVD CVD
Anticoagulative CVD, Dbs
Antiarrhythmic
Antiestrogenic CVD, C
Antiproliferative C
Antiangiogenic C
Antitumorogenic C C
Antioxidant CVD, C
Antiosteoporotic Deg
Anti-inflammatory C, CH, Dig, Deg
Detoxification C, CH, Dig, Deg
Cell Membrane Function All
Cell Regulator Response All
Blood Sugar Regulation CVD, Dbs
Nutrient Absorption All
[omega]6 Antagonistic CVD, C, OH, Deg
Enzyme Modulation C, CH
Menopausal Symptoms C
Renal Protective CVD, Deg CVD, Deg
Weight Management All

Key:

CVD = Cardiovascular Disease

C = Cancer

CH = Cellular Health

Dbs = Diabetes

Dig = Digestive Health

Deg = Degenerative Disease (Lupus, Inflammatory Bowel Disease (IBD),
Irritable Bowel Syndrome (IBS), Other Autoimmune and "itis" Diseases)

All = All Categories

References

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(2.) Simapoulos, . and J. Robinson. The Omega Plan. Harper Collins Publishers, Inc. 380 p. (1998).

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(6.) Setchell, .R. and H. Adlercreutz. The Excretion of Two New Phenolic Compounds (180/442 and 180/410) During the Human Menstrual Cycle and in Pregnancy. J. Steroid Biochem. 11: xv-xvi. (1979).

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(11.) Liggins, J., R. Grimwood, S. Bingham. Extraction and Quantification of Lignan Phytoestrogens in Food and Human Samples. Anal. Biochem. 287(1): 102-109. Dec. (2000).

(12.) Richard, S. E. Health Effects of Flaxseed Mucilage, Lignans. Inform. 8(8): 260-265. (1997).

(13.) Adlercreutz, H., K. Hockerstedt, C. Bannwart, et. al. Effect of Dietary Components, Including Lignans and Photoestrogens on Enterohepatic Circulation and Liver Metabolism of Estrogens and on Sex Hormone Binding Globulin (SHBG). J. Steroid Biochem. 27: 1135-1144. (1987).

(14.) Setchell, .R. and H. Adlercreutz. Role of the Gut Flora in Toxicity and Cancer. . Rowland, Ed., Academic Press, London. 315-345. (1988).

(15.) Setchell, .R., A. Lawson, S. Barriello, R. Harkness, H. Gordon, D. Morgan, D. Kirk, L. Anderson, H. Adlercreutz and M. Axelson. Lignan Formation in Man -- Microbial Involvement and Possible Roles in Relation to Cancer. Lancet. 2: 4-8. (1998).

(16.) Setchell, .R. Discovery of and Report of Lignans as Phytoestrogens. Proceedings, 57th Flax Institute of the US, Fargo, N. D. p. 1-7. Mar. (1998).

(17.) Bowen, P. E. Evaluating the Health Claim ofFlaxseed and Cancer Prevention. Nutrition Today. 36(3): 144. (2201).

(18.) Axelson, M. and K. Setchell. The Excretion of Lignans in Rats: Evidence for an Intestinal Bacteria Source for this New Group of Compounds. FEBS Lett. 123: 237- 342. (1981).

(19.) Setchell, .R. Discovery and Potential Clinical Importance of Mammalian Lignans in Flaxseed in Human Nutrition. . Cuonanes and . Thompson, Eds. AOCS Press, Champaign, IL. P. 82-98. (1995).

(20.) Siguel, E. Clinical Applications of Essential Fats and Linolenic Acid: Update 2000, Comments and Discussion. Proceedings, 68th Flax Institute of the US Fargo, ND, p. 213- 224.) Mar. (2000).

(21.) Soy Isoflavones. NNFA Today. Science News. 15(7): 6-7. Aug. (2001).

(22.) Meagher, . and . Beecher. Assessment of Data on the Lignan Content of Foods. J. Food Composition and Analysis. 13: 1-10. (2000).

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(25.) Westcott, . and . Muir. Process for Extracting Lignans from Flaxseed. US Patent 5,705,618. (1998).

(26.) Westcott, N. D. and D. Paton. A Complex Containing Lignan, Phenolic and Aliphatic Substances from Flax and Process for Preparing. US Patent Application. (1999).

(27.) Thompson. ., . Seidl, . Rickard, . Orcheson and .S. Fong. Antitumorigenic Effect of a Mammalian Lignan Precursor From Flaxseed. Nutr. Cancer. 26: 159-265. (1996).

(28.) Jenab, M. and . Thompson. The Influence of Flaxseed and Lignans on Colon Carcinogenesis and b-Glucuronidase Activity. Carcinogenesis. 17: 1343-1348. (1996).

(29.) Serraino, M. and . Thompson. Flaxseed Supplementation and Early Markers of Colon Carcinogenesis. Cancer Letters. 63: 1569-165. (1992).

(30.) Adlercreutz, Y. Mousari, M. Loukavaara and E. Hamalainen. Lignans, Isoflavones, Sex Hormone Metabolism and Breast Cancer. I. Hochberg and Naftalia, Eds. The New Biology of Steroid Hormones. Serana Symposia Publications, Raven Press, NY 24. (1991).

(31.) Kuxzer, MS., . Slavin and H. Adlercreutz. Flaxseed, Lignans, and Sex Hormones. In: Flaxseed in Human Nutrition. . Cuonanes and . Thompson, Eds. AOCS Press, Champaign, IL. P. 136-156. (1995).

(32.) Serraina, M. and . Thompson. The Effect of Flaxseed Supplementation on Early Risk Markers of Mammary Carcinogenesis. Cancer Lett. 60: 135-142. (1991).

(33.) New Flax Technology Can Be Used to Treat Diseases. Resource News International. 16: 24. July. (2001).

(34.) Archer Daniels Midland Signs Exclusive Licensing Agreement for Flax Lignan Technology. PR Newswire. 12:32. July. (2001).

(35.) ADM Licensing Agreement for Flax Lignan Technology. Prepared Foods, e-Newsweekly. July 17, 2001. (.com/newsletter/articles/0701/)

(36.) Unpublished communication with G. Miller, ADM Scientific. Sept. (2001).

Correspondence: Bernard M. Collett

955 Birch Avenue Rifle, Colorado 81650 USA

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